Vice-Chancellor
CCS Haryana Agricultural University
HISAR- 125 004 (Haryana) India
FOREWORD
About one-third of global crop production depends on insect pollination. Most of
the pollinators are wild bees belonging to different genera. In India, much of the work has
been undertaken on various aspects of honey bees ( Apis spp.) alone, which are not only
good pollinators, but are a rich source of honey, wax and other beneficial products as
well. However, in nature, apart from honey bees there exist a large number of solitary
bees such as mining bee, leafcutter bee, alkali bee, carpenter bee, etc also which play
an important role in pollination of various crops and flowering plants growing in the wild.
Depending upon the flower structure and other factors, some of these bees are quite
specific to a particular group of plants. The potential of such bees for pollination remains
underutilized. There are reports of bee decline world over probably because of degradation of suitable environment required by the bees. Factors responsible for this decline
need to be identified.
Our country is rich in diverse flora. So, there is a vast scope for expansion of bee
keeping. It is a good source of supplementary income for the farmers and unemployed
youth, and the products of bee keeping have big export market. The farmers of the
country are, in general, quite poor and they need technological support to boost their
yields and profits.
With the infrastructural support from the Govt., area under protected cultivation
of horticultural crops is gradually expanding, particularly in response to their export
potential, for which new technological innovations would be required. However,
crops grown under such conditions have specific requirements, particularly in terms of
pollination. Therefore, the role of specific pollinators has become more important these
days. The Israeli scientists have perfected the technology of rearing and multiplying
bumble bees ( Bombus terrestris) under controlled conditions, and the farmers in
different countries are adopting this technology for pollination of tomato, capsicum and
other crops grown in polyhouses. With the changing cropping pattern and access to
global markets, new technologies can help the farmers in a big way.
It gives me immense pleasure that the Centre of Advanced Faculty Training (CAFT)
in the Department of Entomology selected an appropriate topic "Advances in BioEcology and Management of Insect Pollinators of Crops" for the advanced training
course. I am sure that this course must have provided an excellent opportunity to the
participants in understanding the behaviour, ecological requirements and other aspects
of various pollinators.
I compliment Dr. R.K. Saini, Professor and Head-cum-Director CAFT, Dr. S. K.
Sharma and Dr. Yogesh Kumar, Course Coordinators, for planning and organizing this
training course and bringing out this compendium. I wish the programme all success.
(K. S. Khokhar)
Dean
College of Agriculture
CCS Haryana Agricultural University
HISAR 125 004 (Haryana) India
MESSAGE
I am extremely happy that the Centre of Advanced Faculty Training (CAFT) in the
Department of Entomology is organizing an advanced training course on "Advances in
Bio-Ecology and Management of Insect Pollinators of Crops" from 21st February to 12th
March, 2012. The presence and species diversity of pollinators on earth is a boon from
the nature to the mankind. Survival of many plant species is dependent on pollinators. In
their absence, it would not have been possible for us to enjoy so many types of food
grains, fruits, vegetables and other materials produced by plants. Apart from their role in
pollination of different plants, they are also useful in a number of ways. Some of
them produce useful materials like honey, wax, venom etc. A number of them are good
predators while some others serve as food sources for other animals. Therefore, there is
a need to understand their ecological requirements and behaviour so that their role could
be recognized not only for increasing crop yields but for maintaining stability of our
ecosystem also.
It is heartening to note that a compendium of lectures delivered during the
training course is being published in the form of a book, which I hope would prove
very useful to the faculty, extension workers and students. I appreciate the efforts
of Dr. R. K. Saini, Prof. & Head-cum-Director CAFT, and his team for planning and
organizing this training course and bringing out this publication.
I wish all success to the organizers.
(Sucheta Khokhar)
Prof. & Head (Entomology)-cum-Director
Centre of Advanced Faculty Training
CCS Haryana Agricultural University
Hisar 125 004, India
PREFACE
The presence of diverse forms of pollinators on earth is a gift from the nature to
the mankind. Different pollinators which include insects like bees, butterflies, beetles,
moths, flies, ants and wasps; birds; bats; and other animals that carry pollen from the
male to the female parts of flowers for plant reproduction are an essential part of natural
and agricultural ecosystems. Without pollination, many plants are unable to reproduce
or would produce fruit and seeds at much lower rates. Agriculture and human
food production is heavily dependent upon "pollination services". Sadly, many native
pollinator populations appear to be threatened or facing uncertain future due to habitat
loss and degradation. This poses a significant threat to the integrity of biodiversity, to
global food webs, and to human health.
Considering the utmost importance of pollinators, the present training course
on "Advances in Bio-Ecology and Management of Insect Pollinators of Crops" was
organized from February 21 to March 12, 2012 with the objective of providing update of
the progress made in this field.
Important aspects covered during this course include species diversity of
insect pollinators; their habitat management, biology, conservation and augmentation;
identification of insect pollinators; factors responsible for pollinators decline,
management of honey bees and their enemies and diseases; pollination syndrome;
management of insect pollinators of crops, fruits, vegetables, fibres and spices;
bio-ecological requirements of bumble bees, megachilid bees and other pollinators;
techniques for domestication of stingless bees, etc. It also included miscellaneous
chapters covering other supportive fields such as reproductive biology of flowering plants,
computer application in Entomology, etc.
Most of the lectures were contributed by the specialists from CCS Haryana
Agricultural University, Hisar. However, some of these were delivered by experts from
Tamil Nadu Agricultural University, Coimbatore; University of Agricultural Sciences,
Bangalore; Dr Y S Parmar University of Horticulture and Forestry, Nauni, Solan, Himachal
Pradesh; SKUAST, Srinagar; Punjab Agricultural University, Ludhiana and by
Dr. V. C. Kapoor, Prof. & Head (Retd.), Department of Zoology, PAU, Ludhiana. Eleven
participants representing 10 SAUs attended this course.
The financial assistance from Indian Council of Agricultural Research (ICAR),
New Delhi and help and cooperation received from different resource persons, faculty
and staff of Department of Entomology and other departments of the University who have
been associated with this course is gratefully acknowledged.
I am indeed indebted to worthy Vice-Chancellor, Dr. K. S. Khokhar, for the
patronage, support and encouragement given by him to this training programme.
I express deep sense of gratitude to Dr. Sucheta Khokhar, Dean, College of
Agriculture, for her enormous help, support and encouragement. I owe my sincere thanks
to Dr. R. P. Narwal, Director of Research, for his cooperation and help. Support from
members of various Committees engaged with this programme and the Course
Coordinators, Dr. S. K. Sharma and Dr. Yogesh Kumar, is thankfully acknowledged.
I hope, this compendium will be of great help to students, researchers and teachers
not only in their academic pursuits, but also in understanding ecological and behavioural
aspects of the pollinators' fauna so that their populations could be conserved and
augmented in nature.
(R. K. Saini)
CONTENTS
No.
Title and Name
1.
HISTORY OF POLLINATION AND BEEKEEPING
S. K. Sharma
1
2.
CO-EVOLUTION OF FLOWERS AND INSECT POLLINATORS
Hans R. Dhingra
5
3.
IMPORTANT INSECT POLLINATORS OF CROPS
S. K. Sharma
13
4.
POLLINATION SYNDROME IN RELATION TO INSECT POLLINATORS
Sunita Yadav and H. D. Kaushik
20
5.
HABITAT MANAGEMENT FOR SUSTAINABILITY OF POLLINATORS
Pala Ram
28
6.
TRENDS IN INSECT POLLINATION OF CROPS
V. C. Kapoor
35
7.
BIO-ECOLOGY AND UTILIZATION OFBUMBLE BEE IN CROP POLLINATION
Raj Kumar Thakur and Jatin Soni
39
8.
BIOECOLOGY AND MANAGEMENT OF LEAFCUTTER BEES
Yogesh Kumar
50
9.
BIOECOLOGY AND MANAGEMENT OF ALKALI BEE
H. D. Kaushik and Sunita Yadav
55
10.
BIOECOLOGY AND MANAGEMENT OF STINGLESS BEES FOR CROP POLLINATION
M. Muthuraman, P. A. Saravanan, K. Vijaya Kumar and P. Priyadharshini
60
11.
CONSERVATION, AUGMENTATION AND UTILIZATION OF WILD BEES
IN CROP POLLINATION
D. P. Abrol
68
12.
POLLINATION BIOLOGY OF SMALL CARDAMOM - A CASE STUDY
V. V. Belavadi
86
13.
ROLE OF INSECT POLLINATORS IN PRODUCTION OF OILSEED CROPS
S. P. Singh
90
14.
ROLE OF INSECT POLLINATORS IN PRODUCTION OF TEMPERATE FRUITS
J. K. Gupta
96
15
IMPACT OF INSECT POLLINATORS ON TEMPERATE VEGETABLE SEED CROPS
Harish Kumar Sharma
101
16.
SCOPE AND LIMITATION OF INSECT POLLINATIONS IN PROTECTED CULTIVATION
Ombir
107
17.
ROLE OF INSECT POLLINATORS IN SEED PRODUCTION OF SEED SPICES
S. S. Sharma and Hasansab A. Nadaf
110
18.
ROLE OF INSECT POLLINATORS IN TROPICAL/SUB-TROPICAL/ARID FRUIT CROPS
H. D. Kaushik, Sunita Yadav and Hasansab A. Nadaf
113
19.
EFFECTS OF CLIMATE CHANGE ON POLLINATOR POPULATIONS
V. V. Belavadi
122
20.
ABIOTIC ENVIRONMENTAL FACTORS AFFECTING BEES ACTIVITY
V. S. Malik
126
21.
QUEEN BEE REARING TECHNIQUES FOR COMMERCIAL BEEKEEPING
Jaspal Singh
130
22.
HONEY BEES : MANAGEMENT AS POLLINATORS
Yogesh Kumar
136
23.
A SIMPLE TECHNIQUE TO HIVE LITTLE BEE COLONIES
M. Muthuraman, S. Kaliamoorthy, N. Ganapathy, G. K. Thangavel,
P. Priyadharshini and K.Bharathidasan
140
24.
REQUIREMENT OF FLORA IN RELATION TO BEE POLLINATOR SPECIES
Sunita Yadav and H. D. Kaushik
143
25.
MITES OF HONEYBEES AND THEIR MANAGEMENT
Rachna Gulati
156
26.
INSECT POLLINATORS' DISEASES AND THEIR MANAGEMENT
B. S. Rana, M. L. Khan and Sapna Katna
167
27.
INSECT POLLINATORS ENEMIES AND THEIR MANAGEMENT
S. K. Kakroo
178
28.
POLLINATION ENERGETICS
D. P. Abrol
184
29.
FACTORS RESPONSIBLE FOR POLLINATORS DECLINE WITH
PARTICULAR REFERENCE TO PESTICIDES
R. K. Saini
196
30.
ROLE OF MELISSOPALYNOLOGY IN BEEKEEPING
G. S. Yadav and Hasansab A. Nadaf
204
31.
SIGNIFICANCE OF COMPUTER USAGE IN BIOLOGICAL SCIENCES
A. K. Chhabra, Pratiksha Mishra and Ashish Jain
207
32.
INTELLECTUAL PROPERTY RIGHTS’ ISSUE IN AGRICULTURE
R. B. Srivastava
220
33.
HISTORY OF INTRODUCTION OF EUROPEAN/ WESTERN HONEY BEE
(APIS MELLIFERA LINNAEUS) INTO INDIA
N. P. Goyal and Pardeep K. Chhuneja
230
34.
BIOSYSTEMATICS OF INSECT POLLINATORS : A BASIC NEED
Sucheta Khokhar
225
HISTORY OF POLLINATION AND BEEKEEPING
S. K. Sharma
Department of Entomology,
CCS Haryana Agricultural University, Hisar
Evolving from short-tongued, spheciform wasps, honey bees first appeared during
the Cretaceous period about 130 million years ago. At that time, present-day continents
such as Africa, India, South America, Australia and Antarctica formed a single landmass
called Gondwana. Germinating in the warm dry Gondwanan climate, flowering plants
called angiosperms developed colours and petal patterns to attract insects, which were
more reliable than wind to transfer pollen. In addition to pollen, flowers eventually produced nectar, providing carbohydrates to their winged vectors. About 120 million years
ago, the honey bee developed its morphologies specifically to collect pollen and nectar
such as increased fuzziness, pollen baskets, longer tongues, and colonies to store
supplies.
As Gondwana gradually broke apart and temperatures cooled dramatically during
the Oligocene-Miocene about 35-40 million years ago, European honey bees went extinct, while Indo-European honey bees survived and began to speciate. Open-nesting
honey bees perhaps evolved before cavity-nesting bees, probably in India, but evidence
is still lacking. In any event, a cavity-nesting honey bee spread east and north about six
million years ago. During a Pleistocene warming about 2-3 million years ago, this bee
spread west into Europe and then into Africa to become Apis mellifera .
Early civilizations quickly mastered honey hunting skills, shown in rock art in Africa,
India and Spain. Egypt, Greece, Italy and Israel developed organized beekeeping centers until the Roman Empire dissolved in approximately 400 A.D. Christianity monasteries and convents then served as apiculture centers until Henry VIII closed them at the
beginning of the Reformation. Science and technology provided the next insights into
apiculture during the Enlightenment.
Honey bees expanded to North America with human-assisted migration during the
17th century. Many Europeans fleeing wars, poverty, land laws or religious persecution
brought extensive beekeeping skills to the United States during the next two centuries.
Meanwhile, English colonists took bees to New Zealand, Australia and Tasmania, completing human-assisted migration of Apis mellifera around the globe.
Beekeeping became commercially viable during the 19th century with four inventions: the moveable-frame hive, the smoker, the comb foundation maker, and the honey
extractor. These inventions still support commercial apiculture. A fifth invention, a queen
grafting tool, allows beekeepers to control genetic lines.
Beekeeping properly started when the man learned to safeguard the future of
colonies of bees be found in hollow tree trunks or elsewhere. Gradually, separate hives
came to be used as substitutes for the natural dwellings of bees; for convenience and
1
safety they were collected together in an apiary. The earliest hive was a log from fallen
tree. The cork and other types of hives were also made mostly during the Stone Age. Pot
vessels were also made during the Neolithic period from perhaps 5000 BC onwards, and
water pots are still used as hives in some Mediterranean lands. In ancient Egypt and
adjoining areas, pipe hives were used. Basket and bone awe hives were used in some
regions. All these primitive hives served the necessary functions of protecting the bees
from wind, rain and extremes of heat or cold; their flight entrances were small enough for
the bees to guard; and there was some other opening through which the beekeeper
could get at the honey and wax which constituted his harvest. But at that time, little was
understood as to what went inside the hive. It was not known whether the "large king
bee" was in fact a female and mother of the other bees. Sexes of the workers and drones
were not known. It was not known that- bees themselves secreted the wax to build
combs and their visits to flowers had anything to do with the formation of seeds and
fruits.
Beekeeping - 1500 to 1851
During the period, several scientific and technical developments took place in beekeeping. During this period, sexes of bees were identified, the queen bee as a female
which laid eggs was published in Spain by Luis Mendez de Torresim in 1586. Then in
England, Charles Butler (1609) showed that drones were male bees and Richard Remnant (1637) showed that worker bees were females. The fact that queen bee can be
raised from eggs was demonstrated by Hickel Jacob in 1568 in Germany, and the queen
mates with drones was discovered by Anton Janascha in Slovenia in 1771. The pollen
which bees collect from flowers is the "male seed" of the flower which fertilizes the
ovum, was discovered in England by Arthur Dobbs in 1750. The part played by bees in
fertilizing flowers was established clearly by C.K. Sprengel in 1793. Between 1650 and
1850 many hives with top bars and frames were invented. But after these two centuries
of efforts, there was still failure. Whatever bars of frames were used, the bees attached
their combs to the walls of the hive as well and combs therefore could be removed from
the hive by cutting them out.
Beekeeping - 1851 and after
During 1851 a remarkable invention in beekeeping was made by Lorenzo Lorraine
Langstroth an American born in Philadelphia. He introduced the concept of bee space.
He deepend the grooves on which bars rested, leaving about 3/8 inch between the cover
and the bars. Langstroth found that the bees did in fact respect the bee space left
between the hives and frames in which the combs-were built; they did not build across
the space and the frames were, therefore truly moveable. The use of moveable frames
led directly to the invention of beeswax foundation by Johannes Mehring in Germany in
1857. Then there were attempts to extract the honey without destroying the comb. This
led to the invention of the centrifugal honey extractor in Austria in 1865 by Major F.
Hrusehka possibly in France. The perfection of the queen excluder by Abbe Collin of
France 1865 enabled the beekeepers to keep the queen, and hence the brood, out of the
honey chamber. By using the bee escape, produced in 1891 by E.C. Porter in the United
2
States, he could get the honey chamber free from bees before he removed the frames of
honey.
The pattern of modem beekeeping was thus established in the half century between
1850 and 1900.
History of insect Pollination
The evolutionary histories of the most important plants in our lives, the flowering
plants or angiosperms, are relatively unknown. Today, angiosperms are almost all
pollinated by animals, the most important being the insects. Some of the largest plant
families are very well adapted for insect pollination (e.g. Orchidaceae ) (Crepet, 1983).
Insect pollination not only conserves energy for the plant (less pollen/ ovule produced),
but insects may play a part in angiosperm diversity (Crepet, 1979). As important to
angiosperms as insects are, the plants are in turn valuable to the pollinator. Insects
derive food, shelter, and breeding places from the plants they visit. Adaptations made
by both angiosperms and insects to exploit the offering of the other have lead to coevolution. Analyzing the way insects and plants interact today can offer only a tiny
picture into the evolution of angiosperms. Examining fossils give us a better idea of the
pollination mechanisms already in place in the angiosperms during their evolution (Crepet,
1979).
Fossil evidence of non-angiospermous plants suggests that pollination by insects
was in place well before the rising of the angiosperms (Crepet, 1979).
Early insects were well adapted for consumption of plant reproductive parts. It is
possible that while feeding on some pollen or ovules, an insect accidentally pollinated
an ancient plant, and could have been the very first step to the evolution of the angiosperms. All four groups of pollinating insects evolved well before angiosperms: Coleoptera (beetles) were very diverse during the Upper Carboniferous, while the Diptera
(flies) and the Hymenoptera (bees and wasps), very important pollinators today, appeared during the Triassic. Lepidoptera (moths and butterflies), also important pollinators, do not show up in the fossil record until the Lower Cretaceous (Crepet, 1979). The
earliest Cretaceous flowers were probably small magnoliid types with few parts, where
the only pollinator reward was most likely pollen. "Generalist" insects probably pollinated these flowers: beetles, short-tongued wasps and flies. By the Middle Cretaceous,
representatives from the Magnoliidae, Hamamelidae, and Dilleniidae appear. Several structures occur in representatives of these angiosperms that suggest insect pollination
(nectaries, petals, staminodes, etc.) (Crepet, 1996). Rosids with characters such as
well-developed corollas, receptacular areas, and nectaries were established during the
Middle Cretaceous, and by the Late Cretaceous, were very diverse ( Basinger and Dilcher,
1984 Gandolfo et. al,1998). At this time the Hymenoptera and Diptera were also going
through radiations, as more "evolved" types (long-tongued bees and flies, etc.) show up
in the fossil record. The more derived floral types of the asterids did not appear until
the Tertiary and coincides with the appearance of stingless honey bees in the Late
Cretaceous (Crepet et al., 1991).
3
The fossils of the New Jersey Raritan Formation are very diverse, with hundreds of
species of plants from mosses to angiosperms. The fossil flowers alone represent over
200 species from several different families of angiosperms. While there are "primitive"
representatives (i.e. magnoliid and nymphaeacious flowers) in this formation, there are
also more "advanced" representatives. These flowers contain characteristics suggesting
"advanced" insect pollinators from possible reward substances to viscen thread on
pollen. Such advanced pollinators, as well as other insects, have been found encased in
amber in this formation (Michener and. Grimaldi, 1988, Grimaldi et al. , 1989, Engel,
2000). As the earth gives up more of its fossil treasures, we will eventually gain a better
understanding of angiosperm/insect co-evolution.
Suggested Readings
Abrol, D. P. 2009. Bees and Beekeeping in India . Kalayani Publishers, Ludhiana.
719 pp.
Crepet, W. L., 1983. The role of insect pollination in the evolution of the angiosperms. In
: L. A. Real [ed.] Pollination Biology , Academic Press. p. 29-50.
Crepet, W. L., 1979. Insect pollination : A paleontological perspective. Bio Science
29 (2) : 102-108.
Proctor, M., P. Yeo, and A. Lack, 1996. The Natural History of Pollination. Timber Press,
Portland, Oregon. 479 pp.
4
CO-EVOLUTION OF FLOWERS AND INSECT POLLINATORS
Hans R. Dhingra
Department of Botany and Plant Physiology,
CCS Haryana Agricultural University, Hisar 125 004
Flowering plants are the most successful group of land plants, containing over 90%
of species and dominating almost every terrestrial ecosystem. This evolutionary
success is due, in part, to their sophisticated reproductive biology centred on the eponymous flower, where female gametophytes (embryosac) are hidden and protected by carpel, animals are the principal transport vectors of the sperm containing male gametophytes (pollen grains), and fertilization no longer requires water for fertilization due to
siphonogamy. This combination of reproductive traits has permitted the evolution of an
extra-ordinary array of mating and pollination systems that we are just beginning to
understand. At a time of unprecedented human population increase and biodiversity loss,
research on plant reproduction, with its potential to increase crop yields and deliver food
security and to guide effective conservation strategies, has never been more important.
Success story of sexual reproduction and subsequent seed formation starts with the
deposition of pollen on the stigmatic surface through some vector.
Flower has been an object of great appreciation by men of all ages and stages, and
of different professions and interests from the time immemorial due to its aesthetic
beauty and variations and variety of colors, shape configuration, assemblage fragrance
and other attributes of visual attractions. The modern flowering plants are an outcome of
constant experimentation of nature through the last 2.5 million years. An inquisitive
naturalist would like to probe into these intricacies in variations in flower structure to
find out cause and determining factors in floral evolution and modifications in floral parts
with an objective to devise proper method of pollen transfer to ensure successful pollination and to economize the energy by reduction of unproductive accessory whorls to
divert the saved energy towards the production of healthy seeds. Curious inferences
have been drawn on the role of pollinators and mode of pollination in determining floral
evolution. Reduction in floral parts however has often been interpreted from evolutionary
point of view but very little from the point of reproductive efficiency and successful propagation of healthy progenies. A systematic and logical evaluation of flower will lead us to
the conclusion that all these features are outcome of nature's constant and untiring
experiment in search of a system of legitimate pollination to ensure maximization of
production of healthy and vigorous seeds to ensure the sustainenace of the species.
Each flower, in general, is either terminal or axillary in position and comprises of four
different whorls viz. , green calyx, coloured corolla (non-essential whorls), androecium
and gynoecium (essential whorls). Entomophilous flowers in general, are characterized
by their conspicuousness, odour and irregularity of parts, nectar and honey guides. The
various flower traits and combination thereof that fondly attracts one or other type of
pollinator is known as pollination syndrome. The flowers are rendered conspicuous by
their large sized or richly colored corolla. The petaloid bracts of Bougainvillea, sepals of
5
Clematis and staminodes of Canna are the unusual attractive structures. In Mussaenda,
one of the sepals develops into large white attractive leaf structure (Fig. 1). Long and
colored staminal filaments of Callistemon, Mimosa , filamentus carona of passiflora etc.
make the flowers conspicuous. If the flowers are small, they are frequently held together
in large assemblage (inflorescence) such as heads, umbels, corymbs or cymes. In heteromorphic heads like those of sunflower, the peripheral ray florets are chiefly attractive
in functions (Fig. 2). The group of flowers borne on a flowering axis (peduncle) is called
as inflorescence. Inflorescence is broadly categorized as racemose (indeterminate
growth) or cymose (determinate growth). The main kind of racemose inflorescence is the
raceme and other kind of racemose inflorescences can all be derived from this one by
dilation, compression, swelling or reduction of the different axes (Fig. 3A, B). A. raceme
is an unbranched, indeterminate inflorescence with pedicellate (having short floral stalks)
conspicuous flowers along the axis. Different types of racemose inflorescence include:
A spike is a type of raceme with flowers that do not have a pedicel and thus flowers
are sessile
A corymb is an unbranched, indeterminate inflorescence that is flat-topped or convex due to their outer pedicels which are progressively longer than inner ones.
An umbel is characterized by short axis and multiple floral pedicels of equal length
that appear to arise from a common point.
A spadix is a spike of unisexual flowers enclosed or accompanied by a highly
specialised bract called a spathe. It is characteristic of the Araceae family.
A flower head or capitulum is a much contracted raceme in which sessile flowers
are borne on an enlarged flattened peduncle. It may be homomorphic or heteromorphic. It is characteristic of Asteracaceae (Fig. 3A).
Cymose inflorescence is further divided as monochasial, dichasial or polychasial. In
monochasial cyme, the main axis ends up in a flower and one secondary branch is
produced at one time. Depending upon the plan of production of secondary branches, it
may be helicoid (successive branches on the same side, Hamelia ) or scorpoid (successive branches on alternate sides). In dichasial cyme two lateral branches are produced
at a time which again ends up in a flower and the process is repeated.eg. Jasminum,
members of Caryophyllaceae. In polychasial cyme more than two secondary branches
are produced thereby looking like an umbel and hence also known as umbelliform cyme.
A reduced cyme that grows in the axil of a bract is called a fascicle. A verticillaster
is a fascicle with the structure of a dichasium; it is common among the Lamiaceae. The
genus Ficus (Moraceae) has an inflorescence called syconium and the genus Euphorbia
has cyathia (sing. cyathium), usually organised in umbels (Fig. 3B).
The flowers that open in night ( Jasminum, Alstonia, Yucca ), the corolla is invariably
white. In Mimusops flowers, odour is the attractant while in Michelia odour and color
together are the attractant. Flowers of Aristolochia , Amorphophallus ( Fig. 2), Sterculia
6
emit foetid smell which attracts dung and carrion flies. The directive stimulus of smell is
distinguished from distance by most of the insects. Irregularity of floral parts adds much
to the comfort and convenience of insect visitors because there is a striking correspondence of structure between the pollinating insects and flowers they visit. Many flowers
provide a landing stage for the visitor; some furnish perches, expansions, labellum, etc.
for their alighting. All sorts of lobes, sinuses, pegs and knobs are means to attract and
accommodate the particular insect that visit them. Papilionaceous flowers and orchids
have such peculiarities.
Nectar is the chief food supplied by the entomophilous flower to the insect visitor. It
is a sweet secretion of certain glandular structures called nectaries. In most zygomorphic flowers, the nectaries are hidden at the bottom of corolla tube. In Impatiens,
Tropaeolum etc. one of the sepals is produced into a spur where nectaries are located.
In Delphinium , on the other hand a spur is formed by a few sepals and a part of torus. In
papilionaceae nectar is placed at the base of staminal sheath. Some peculiar markings
and special outgrowth found in certain flowers are known as' honey guides'. These help
insects to reach concealed nectaries and in doing so, the insects are made to effect
cross pollination. In Vicia faba , the extrafloral nectarines appear on the stipules. On the
other hand, extra-floral nectaries are present on the cup like involucres in Euphorbia
splendens, E pulcherima.
Some of the showy and fragrant flowers offer pollen to the insects. Such flowers are
'pollen flowers' which may be used as food by the insects e.g. Anona. Insect pollinators
such as honeybees ( Apis mellifera), bumblebees ( Bombus terrestris ) and butterflies
( Thymlicus flavus ) have been observed to engage in floral constancy, which means they
are more likely to transfer pollen to other conspecific plants. This can be beneficial for
pollinisers as flower constancy prevents the loss of pollen during interspecific flights
and pollinators from clogging stigmas with pollen of other flower species.
Formation of various types of Inflorescence
Varied types of infloescences are result of nature's experiments for achieving best
pollination mechanism. Raceme inflorescence characterized by long peduncle and long
pedicillate flowers is useful if the flowers are conspicuous by themselves. The smaller
and inconspicuous flowers could attract the insects only through assemblage to form
inflorescence with massive appearance. This could be achieved through the suppression
of peduncle, approximation of flowers, reduction in the length of pedicels and evolving
sessile flowers. Gradual reduction in the size peduncle and pedicels lead to evolution of
the spikes, catkins and spadix type of inflorescence through while reduction of peduncle
yielded the corymb, umbel and ultimately capitulum type of inflorescence. The efficiency
of the pollinator in capitulum is increased substantially as single pollinator can pollinate
a large number of flowers due to assemblage into pseuo flower (Fig. 2). Conversion of
peduncle into urn shaped structure and arrangement of unisexual flowers at two levels
with an ostiole at the top lead to the evolution of Hypanthodium type of inflorescence in
Ficus. This modification advantageously serves flowers through the services of thrips
and wasps searching for brooding place. The efficiency so achieved increased the pro7
duction of sufficient, healthy and viable seeds for the continuity of the parent species. It
was therefore, reasonable for the plants to go for an experiment to decrease the number
of ovules and carpels per inflorescence. This is achieved in cyathium type of inflorescence which is characterized with single female flower with three ovules but innumerable stamens, each representing a flower (Fig. 3B). All the other floral whorls have been
eliminated from the scene thereby diverting the saved food and energy for the production
of vigorous seeds. To reduce the tissues of the calyx and corolla in certain families,
benefit has been taken by reduction in the length of pedicles and peduncle. The approximation of the flowers through this method resulted into the formation of catkin and ultimately the capitulum (head) with reduction in non essential accessory organs like sepals and petals (Fig. 3A). Probably this reduction in perianth (accessory whorls), very
much prevalent in Apetalae, was necessitated as they turned to be more hindrance than
aid in pollination.
Modifications in the shape of flowers to meet pollination requirement
Leppik (1957a, b) classified flowers into seven types- paleomorphgic oramorphic,
haplomorphic, actinomorphic, pleomorphic, stereomorphic, zygomorphic and paramorphic.
Among these, amorphic, haplomorphic, actinomorphic predominated the first one hundred million years of the origin of angiosperms while next 60 million years saw the
predominance of pleomorphic and stereomorphic flowers. Zygomorphy is more recent
and has been in existence for the last 10 million years and paramorphic is the most
recent. All these categories of flowers can be correlated with the type of pollinators
(Leppik 1977) which existed during the respective periods (Table 1). The amorphic flowers are characterised by clustering of the white or yellow semaphylls which can't be
discriminated from normal foliage. These flowers are asymmetrical, with numerous stamens and carpels and usually subtended by bracts or discoloured upper leaves; e.g.
Salix discolour Echinops ritro. These flowers do not have much to offer to the pollinators. The insects visit these flowers in search of edible parts like accessory whorls
(sepals, petals) or pollen. The haplomorphic flowers are characterized by spiral arrangement of accessory whorls in a hemispherical form. Accessory whorls have numerous
sepals and petals. Insects are attracted towards these flowers due to the distinct colors
like white, green yellow or pink of semaphylls. These flowers are easily accessible to
unskilled pollinators like beetles, flies and bugs. The primitive Ranales (Magnolia,
Nymphaea ) have this type of flowers. Although visual distinction was marked both in
case of semaphylls and anthers, there was no distinct variegation in flowers. The Cretaceous period (100 million years back) was predominated by such flowers and in modern
time these are present in primitive forms. Among the advanced ones, compositae possibly resembled the type through their pseudo flowers.
Radial symmetry made the actinomorphic flowers attractive. The nectar is the main
attraction. Floral parts are arranged at one level with definite number of parts and size
e.g. Anemone, Caltha . Attractiveness of these flowers increased through narrowing of
petals and by color contrast between white petals and yellow stamens. Since the nectar
and floral parts are present at the same level, it is apparent that nectar secreted cannot
8
Table 1.
Relative ability of pollinating insects exploiting various types of flowers (After Leppik,
1977)
Type Class
Period (Million
Years Ago)
Insect Pollinator Group
Zygomorphic
Quarternary (10)
Hemiptera,
Thysaneuraptera,
Lepidoptera, Hymnoptera
Stereomorphic
Tertiary (60)
Hemiptera,
Thysaneuraptera,
Lepidoptera, Hymnoptera
Pleomorphic
Tertiary (60)
Orthoptera, Neuroptera,
Coleoptera, Hemiptera,
Thysaneuraptera,
Lepidoptera, Hymnoptera
Actinomorphic
Cretaceous (100)
Orthoptera, Neuroptera,
Coleoptera, Diptera,
Hymnoptera
Haplomorphic
Cretaceous (100)
Orthoptera, Neuroptera,
Coleoptera, Diptera,
Hymnoptera
Amorphic
Cretaceous (100)
Coleoptera, Diptera,
Hymnoptera
9
be easily held at the base of flowers unless a provision is developed for such a purpose.
Surmisingly the spur seen in primitive flowers seem to be a step in this direction and
twisted aestivation as seen in Malvaceae has been an effort in the achievement of this
objective.
The pleomorphic flowers are characterized by distinct number of floral parts and
their alternating arrangement. This situation was exploited by the skilled and intelligent
pollinators. The insects belonging to Hymnoptera can recognize and memorize such
patterns of flowers. It has been an advantage that beetles can't recognize such patterns.
This specificity of pollinators helped avoiding the mixing of pollen of flowers from different species and varieties. This special feature has been further exploited by nature by
evolving stereomorphic flowers, which in addition to definite number of floral parts,
developed gamopetalous corolla with nectar concealed at the base of corolla tube e.g.
Narcissus, Aquilegia . Meanwhile to make the pollinators more effective and enjoy special treatment, the later developed long proboscis (butterflies). Further refinement lead
to the evolution of zygomorphic flowers. These flowers are with bilateral symmetry, parts
usually reduced in number and irregular e.g. Cyperidium, Salvia . In such flowers, the
very advantage of numerical patterns has been lost (Labiatae) and the actual component
namely the number of floral parts cannot be easily recognized. Through this the corolla
tubes has become very much narrow (Fig. 4).
Paramorphic flowers came up in the recent evolutionary history. These are characterized by irregular rudimentary shape but cannot be divided into two equal halves by
longitudinal division. Although their appearance is of unorganized primitive type, they
represent the most advanced floral type. Families of Scitaminae and some of the
orchids like Sterlitzia reginae represent this type of flower (Fig. 5)
Co-evolution of flowers and pollinators
Aesthetic beauty of flowers is determined by distinct attributes like colour, odour,
configuration, size, assemblage of floral parts, etc. The corresponding variation in
preferences for food and adaptation of characters of pollinators belonging to different
taxonomic groups is another feature of interest. Leppik (1957 onwards) provided
evidences in favour of flower-pollinator co-evolution. He classified flowers as explained
earlier according to shapes, iconic numerals and serialized them in sequence of
evolutionand correlated their characters with insect pollinator. It was assumed that preangiospermic flower resembled flower of Cycodea of Cycadophyta, which he designated
as paleomorphic flower which probably originated during Triassic period. These flowers
were amorphic and pollinated by unskilled pollinators like by beetles, flies, stoneflies,
wasps and thrips. Various modifications of flowers in relation to the insects gave rise to
haplomorphic, actinomorphic, pleomorphic, stereomorphic and finally zygomorphic flowers. The evolutionary history suggests that actinomorphic flowers existed during Cretaceous and Mesozoic periods (Table 1). Available evidences suggest that Thysanura,
Protura and Collembola were the first pollinators which fed upon pollen and floral parts.
However, their poor mobility came in the way in carrying pollen far off. The haplomorphic
or actinomorphic Magnolia type flowers appear to be well suited for pollination by these
10
Fig. 1. Floral attractants in flowers of (Left to Right) coloured bracts of Bougainvillea , sepals
of Clematis, stamens of Callistemon , involucres of Euphorbia splendens ( Cyathium ),
o n e o f t h e s e p a l s o f Mussaenda, f i l a m e n t s c o r o n a o f P a s s i f l o r a , s p a t h e o f
Amorphophallus, detailed floral structure of Amorphophallus, Aristolochia flower
Capitulum of Family Asteraceae
Florets of Sunflower
Honey bee pollinating sunflower
Fig. 2. Clustering of small flowers in to pseudo flower (Capitulum inflorescence) with
peripheral ray florets making it conspicuous to the insect pollinators (top), two types
of florets in sunflower and honeybee in action
Spike
Raceme
Corymb
Umbel
Spadix
Capitulum
Fig. 3A. Types of Inflorescence
Helicoid Monochasial Cyme
Scorpoid Monochasial Cyme
Dichasial Cyme
Polychasial Cyme
Verticillaster
Hypanthodium
Fig. 3B. Types of Inflorescence
Cyathium
Fig. 4. Types of Pleomorphic Flowers on the basis of Iconic numerals) Left to Right :
Anthurium andeanum (spadix subtended by a colored leaf), Commelina tuberose
(Showy petals subtended by green leaf), Sagittaria sagittifolia (trimerous), Eruca
sativa (tetramerous), Lopozia coronata (unilateral tetramerous), Dianthus armeria
(pentamerous), Lonicera japonica (abilateral pentmerous), Ornithogalum arabicum
(hexamerous) and Sanguinaria candenziz (octamerous), after Leppik,1977
Fig. 5. Paramorphic flowers . L-R Maranta leuconeura, Strelitzia reginae
wingless insects. Pollination by these insects probably was by chance. The improvement in the mouth parts of insects brought about a change in their feeding habits which
led to evolution of insects matching the flower. As a result, the Coleopterans undergoing
definite metamorphosis, with biting mouth parts and adults with wings entered the scene
of pollination. Subsequently, the extrafloral nectarines present in some plants belonging
to Umbelliferae, Saxifragaceae and Rosaceae shifted into the flower to become intrafloral
in order to attract and feed the visitor. This was probably the time when Nematocerans
(Diptera) with an ability to move fast appeared as pollinators. These insects were characterized by their preference for nectar. Modifications in the flower to give rise to gamopetalous flowers in Boraginaceae, Primulaceae, Apocyanaceae and Asteraceae and the
presence of nectar in the deeper region at the base of corolla staminal tube or at the
base of disc made it necessary for a pollinator to develop long proboscis. Brachycerons
of Diptera were the first to develop such a system. Another group among the Dipterans
that developed better attributes and better proboscis was Cyclorrhapa . These insects
pollinated mostly bilabiate flowers of Labiatae which evolved during Cretaceous period.
During the Eocene, the Lepipterons (butterflies) which exclusively visited the flowers for
nectar came in to existence. The butterflies developed proboscis with a length up to 25
mm. Nectar specificity was another trait developed during the course of floral evolution
in order to attain diversity with which bees and wasps co-evolved. Leppik (1977) opined
that insects gradually developed a sensory system to recognize different forms of flowers which became inherited instinct and senses which helped them searching food and
its selectivity.
Foregoing facts evince that adhesion, cohesion, reduction in the number of floral
parts, elaboration of floral structure, shifting of nectaries from extrafloral to intrafloral
positions and thereafter to the deeper regions of flower, were correlated with specific
characters of pollinators available during various geological eras. Present day flowers
are therefore are outcome of selection through million years in an attempt to benefit the
pollinators and at the same time drawing maximum services out of them. The zygomorphic flowers which are considered highly advanced came in to existence during the
Quarternary period and it is evident from a systematic study of floral evolution that the
origin of zygomorphy from actinomorphy was not linear sequence but was a parallel
process. Existance of zygomorphy in Ranales as well as in advanced families of both
monocot and dicot groups including Sympetalae and Synandrae adduces support to this
contention. The concept of co-evolution of flowers and pollinators further suggests that
every instinct of the insect visitor ensures successful pollination (Leppik, 1977). At the
same time, the flower fully satisfies the insect's requirement for food, shelter, brooding
place and even the sex depending upon the purpose of visit of the specific visitor.
The co-evolution of the meganosed fly like Prosoeca ganglbaueri in southern Africa
and the plants like mountain drumstick ( Zaluzianskya microsiphon ) and Pelargonium
suburbanum is a tale of extreme specialization. As floral tubes became longer, insects
with longer proboscis (4 inches) are favoured by natural selection. Similarly, hawkmoths
( Agarius convolvuli) are often tightly associated with the Crinum bulbispermum as its
floral tubes matches the length of proboscis of that hawkmoth. The idea that a plant
11
species might become dependent for pollination on a single species of animal goes
back the writing of Charles Darwin. For instance, Darwin noted that the floral spur of
Malagasy orchid ( Angraecum sesquipedale ) contains pool of nectar almost 12 inches
inside the opening of the flower. He predicted that orchid must be adapted to a moth
pollinator with long proboscis. Although there is very well coordination in floral modifications and modifications in the mouth parts of insects, in the event of loss of these
specific pollinators due to changes in their habitat and also due to loss of other insects
they parasitize during their larval stages, seed production threatened.
Suggested Readings
Leppik, E. E. 1977. Floral Evolution in Relation to Pollination Ecology. Today and
Tomorrow's Printers and Publishers, New Delhi.
12
IMPORTANT INSECT POLLINATORS OF CROPS
S. K. Sharma
Department of Entomology,
CCS Haryana Agricultural University, Hisar
Pollinators provide an ecosystem service that enables plants to produce fruits and
seeds. Pollinators are found in diverse groups of the animal kingdom, including birds,
bats, reptiles, insects etc. Among the several animal, insect dominate in providing pollination services to several plants. The process of insect pollination is believed to be the
basis for the evolutionary history of flowering plants, spanning at least 135 million years.
Two third of the world's 3000 species of agricultural crops require animal for pollination.
Animals provide pollination services for more than 75% of all staple crops and for 90% of
all the flowering plants of the world. About 70%of the world's plants require a pollinator
to produce fruits/seed of which 35% are crop species and this account for one in three
mouthfuls of food and drink we consume. Pollinators play a key role in enhancing the
vigour and growth, conserving plant diversity, mixing of gene pool of plants for increased
survival and hybrid seed production. Pollination by honey bees and other pollinators is
capable of enhancing the quantity and quality of several crops like rapeseed and
mustard, sunflower, niger safflower, bersem, pigeon pea, apple mango, citrus, guava,
litchi, ber, phalsa, gooseberry, coriander, cauliflower, radish, onion, cucumber, etc.
Among the pollinators, insect mainly belonging to the orders of Hymenoptera,
Lepidoptera ,Coleoptera, Diptera, Hemiptera, etc. are the most common and dominant
pollinators in various regions .The pollinators are usually know to live in equilibrium with
nature. Among the insect hymenopterans (largest and diversified assemblages of beneficial insect with nearly 250,000 described species) are highly evolved and constitute the
most important group of pollinating insect. Even in hymenoptera, bees belonging to the
super family Apoidea-containing an estimated 25,000 described species including wasps,
ants, chalcids, ichneumons, sawflies, etc belonging to 250 genera and 11 families are
regarded as the most important group of insect pollinators. In India, no estimates are
available about the faunal complexity of bees but an estimate of about 1000 species is
considered to be somewhat realistic among the bees, the bumble bees and true honey
bees, are the most dominant, specialized efficient and dependable pollinators. Honey
bees have an edge over all other pollinators because their populations can be easily
managed and precisely manipulated as per pollination requirement. India is fortunately
endowed with four species of true honey bees and nearly half a dozen species of
stingless bees. In the present article important insect pollinators of crops are discussed.
Digger Bees/Mining Bees
Many ground-nesting bees ( Andrena, Colletes, and other species) are known as
digger bees, mining bees, or sand bee2s. They excavate nests in the ground, leaving
small mounds of soil aboveground. They often hide their nest entrances beneath leaf
litter or in the grass (Smith, 1998). All digger bees are solitary, but some nest in dense
13
aggregations. These bees pollinate a variety of plants. They are drab, solitary, and rarely
noticed, yet they may be the most abundant wild pollinators in the field.
There are many species of digger bees found throughout North America. Most of
these bees are known only by their Latin binomial names, although they are sometimes
referred to as polyester bees. When the females build their nests, they line them with a
polymeric secretion that looks shiny and synthetic. This material is waterproof, highly
resistant to decay, and protects larvae while they are in the ground.
Bumble bees ( Bombus spp.)
Bumble bees are highly social, like honeybees, but with smaller, less structured
nests, consisting of one to five hundred bees. Bumble bees work harder, faster, and at
cooler temperatures than honey bees (Light, 1994). They prefer to nest underground, in
undisturbed meadows, old barns and woodlots (Byczynski, 1998).
Artificial nests can be made out of old Styrofoam coolers or wooden boxes. To make
a nest, drill drainage holes in the bottom and stuff the box with upholsterer's cotton.
Make a hole in one side and place the box 6-12 inches underground. Connect the box to
the soil surface with a piece of old garden hose, fitted into the hole in the box (Woodier,
1998).
Bumble bee colonies are annual; the entire colony dies out each year and leaves
only inseminated queens to hibernate through winter. The queen will start a new colony
in spring. After she raises the first workers, she concentrates on laying eggs. She will
lay about 20 eggs a day for the rest of her life, which lasts about another 18 weeks
(Gunstone, 1994). Most workers live for about a month. Larger bumble bee workers
collect food and smaller ones maintain the nest and the young larvae. The size difference is largely dependent on the amount of food the bees eat while they are larvae.
Colonies raise males and new queens towards the end of the growing season, usually
between August and October.
Red clover is an excellent forage crop for bumblebees. By also providing forage
plants that bloom eight or nine weeks ahead of red clover, growers can almost assure
themselves of bumble bee colonies. Bumble bees pollinate tomatoes, eggplants,
peppers, melons, raspberries, blackberries, strawberries, blueberries, and cranberries,
just to name a few (Smith, 1998). Bumblebees are the only pollinators of potato flowers
worldwide.
Bumble bees can be raised artificially, but it's probably easier to attract natural
populations. Several companies are now using a patented process developed by European scientists for rearing bumble bees. The companies are charging users from $150 to
$300 per colony. The high cost limits the bees' use to pollinating high-value crops in
greenhouses. More than 300,000 colonies are reported to be in use in greenhouses in
Europe and North America. A colony lasts for about three months in a greenhouse, after
which it must be replaced (Rollie, 1997).
14
Sweat Bees (Halictidae family)
Though most species of this small bee, found throughout the U.S., are black or
brownish, some, such as Agapostemon femoratus , are bright metallic green. All species nest in the ground. Halictids have a range of nesting habits, from dispersed solitary
nests to densely situated ones with individual bees sharing common entranceways to
primitive social arrangements Lateral tunnels end in a single cell. Halictid bees are
common insects and good general pollinators (Wright, 1997).
Sweat bees take their name from their habit of landing on people to lick the salt from
their skin. Like most solitary bees, sweat bees are nonaggressive and will sting only if
you swat at them.Unlike other mining bees, halictid female's mate before hibernating for
the winter, so they can begin nesting earlier in the spring (Smith, 1998). This allows
them to raise only daughters during the growing season, much like bumblebees. Males
are raised in late summer or early autumn.
Alkali Bees ( Nomia melanderi )
The alkali bee is a solitary ground nesting bee native to western North America. As
its name suggests, it can be found nesting in alkali soil. It prefers to nest in bare soil
that remains moist but not wet, and dry on top. This occurs naturally in areas where a
layer of hard pan exists in alkali soils. The alkali salts seal the top of the soil, holding in
the moisture.
The bee is slightly smaller than the honey bee with yellow or green iridescent bands
on the abdomen. The females carry pollen on the hind legs and dig holes in the soil
where they make their nests. Most nest cells are between 4 and 8 inches below the
surface. The pollen is molded with nectar into a ball. The female then lays an egg on the
ball. The egg hatches and the larva feed on the pollen and nectar ball until it reaches the
mature larval stage. It overwinters in this stage and then pupates and emerges as an
adult in the spring after a sufficient number of heat units have accumulated. There is
usually a single generation each year.
The alkali bee was among the first of the solitary bees to be used for pollination of
alfalfa in the western U.S. (Keven et al., 1998). This native bee occurs naturally in areas
west of the Rocky Mountains and nests in moist alkaline soils near natural seeps and
springs (Wright,1997). Western scientists and farmers attract this wild bee by building
nests that simulate natural in-ground nests in alkaline soil. These nests are vertical and
reach down a foot or two into the soil. Although alkali bees are solitary, individuals nest
near each other (Wright, 1997). Adults are black with metallic-colored bluish, greenish,
or yellowish bands circling the abdomen (Torchio, 1990). The larvae overwinter in their
cells, then pupate and emerge from the soil in late spring or early summer, depending on
temperature and moisture of the soil (Torchio, 1990). They rarely use their stings. The
alkali bee also pollinates onions, clover, mint, and celery (Wright, 1997). An artificial
nesting bed can be constructed where bees are desired. An area of silt loam soil is
ideal, but the bees will nest in other soils. Next the area should be excavated 1 to 3 feet
15
deep. The site should then be lined with an 8 mil plastic tarp. A layer of straw is added
to protect the tarp. Then a layer of 1 inch gravel 8 to 10 inches deep is placed over the
straw. The gravel helps to spread the water evenly throughout the bed. Straw or burlap is
then added over the gravel to keep soil from plugging it up. Concrete stand pipes are
then placed at regular intervals throughout the bed. These are used to irrigate the bed
from the bottom. Next the soil is added back to the site and packed down. It is important
to make the bed convex or mounded so that rain water can not form puddles on the bed.
Lastly, salt is added to the top at the rate of 1 to 2 pounds per square foot to seal in the
moisture. Water is added through the stand pipes to maintain the moisture between 8
and 32%. Alkali bees can be obtained in cubes of soil which are then placed in the new
artificial bed. Adults can also be transferred to new beds. Small holes are punched into
the bed with a pitchfork, and then adults collected from another site are released at the
new site at night. It is possible to have populations of up to 125 nests per square foot in
artificial beds. The female alkali bee has a stinger but rarely uses it. No protective
clothing is needed when working near these bees. The alkali bee is an excellent pollinator of alfalfa and onion seed.
Squash Bees ( Peponapis pruinosa)
Squash bees, which are related to carpenter bees, collect pollen and nectar only
from the flowers of cucurbits (squash, pumpkin, and gourd). These solitary bees are
found throughout the U.S., except in the Northwest (Wright, 1997). The bees nest in
underground burrows. They become active at dawn, visiting cucurbit flowers until midday
when flowers closed. As a result, they typically start to pollinate the crop before honeybees are abroad and have finished by the time honeybees are at their most active, from
midmorning on (Keven et al ., 1998). They have life spans of about 2 months, until the
food source is gone (Wright, 1997).
Leafcutter Bees ( Megachile spp.)
Leafcutter bees are solitary bees, usually grayish in color, native to woodland areas
(Smith, 1998). There are more than 140 species found in North America (Wright, 1997).
They nest in ready-made wooden cavities, in hollow plant stems, and in drilled wood
nesting blocks. The females cut pieces of leaves to line their nests. They can be rather
particular about the leaves they use. One species, Megachile umatillensis , a bee native
to the western U.S., cuts leaves only from an evening primrose (Oenethera pallida ) (Christopher and Anthony, 1991).
Leafcutter bees prefer legume blossoms (Wright, 1997), but they will pollinate other
crops, like carrots (Smith, 1998). They are most active in summer, when the temperature rises above 70°F (Polochic, 1996). Leafcutters are efficient; 150 leafcutters can do
the work of 3000 honeybees (Smith, 1998). They are gentle and ideal for greenhouse
work (Smith, 1998).
The alfalfa leafcutter bee, Megachile rotundata , is widely used for alfalfa pollination.
Although not a native bee (it hails from Eurasia), it pollinates alfalfa better than any
16
other insect (Polochic, 1996). The bee is roughly half as big as a honey bee, with lightcolored bands on its abdomen. Barry Wolf Farms in Carrot River, Canada, is the largest
broker of leafcutter bees in Canada (Polochic, 1996).
Carpenter Bees ( Xylocopa spp.)
Carpenter bees are some of the largest bees and have a blue-black, green or purple
metallic sheen. They excavate their own nest tunnels in wood, rather than use preexisting cavities, but they will re-use old nests. They burrow into dry wood pretty much
anywhere they can find it, but they prefer soft woods like pine, and avoid wood that is
painted or covered with bark. A nest consists of a round entrance hole (½" in diameter)
and a tunnel back from it that can extend up to several feet. Carpenter bees become
active when temperatures climb into the 70s in the spring. Mating occurs in April. Carpenter bees are longer-lived than most solitary bees (Christopher and Anthony, 1991).
There are 730 species of Xylocopa world over.
There are also 20 species of Ceratina (dwarf carpenter bees) native to North America
(Christopher and Anthony, 1991). Male carpenter bees can be annoying, since they tend
to buzz around your head. They have no sting, however, so they are completely harmless. The females possess a sting but they very rarely use it. Although carpenter bees
can pollinate several crops, including passionfruit, blackberry, canola, corn, pepper, pole
bean, and rhododendron. These bees are excellent pollinator of cotton in Pakistan, India
and Egypt.
The small carpenter bee of genus Ceratina are also important pollinator of several
crops including fruit crops like peach.
Mason Bees (Osmia spp.)
Bees in the genus Osmia are found throughout the U.S. All the bees in this family
have similar nesting requirements. They do not excavate their own nests, but use existing holes instead. They can nest in straws or in wood blocks drilled with 5/16" holes.
They are gregarious bees, so the nests should be close together. Placing the nests
close to streams is advantageous, since mud for nest building can be collected there
(Ron and Klostermeyer, 1981).
Mason bees are so called because they construct their nests out of materials like
mud and small pebbles. Eggs are laid in tubular cells, with up to 11 cells per nest. The
female determines the sex of the egg and lays male eggs closer to the entrance hole.
This assists in perpetuating the species in two ways. First, the males are more accessible to predators than females, and second, males emerge several days before females. If the female "at the back of the line" emerges first, she opens the cell of the next
female and nips at her to urge her out of the nest. This continues down the line until all
females have emerged from a single nest tube (Christopher and Anthony, 1991).
The nests of Osmias ssp. should be positioned so that they receive morning sunlight. Put the nests up in late winter or very early spring, before the bees begin nesting
17
and remove them after nesting is completed. If the blocks are stored outdoors over
winter, the bees will emerge after temperatures have reached 55°F. Wherever the boards
are stored, they must be kept out of rain and snow (Ron and Klostermeyer, 1981).
If nests are left outside, low winter temperatures may kill bees. Warm spells in late
winter may draw bees out of the nest prematurely, killing even more when cold temperatures return. By storing bees under refrigeration, they can remain dormant until spring
arrives. To build up large populations of mason bees, store the nests under refrigeration
at 35-40°F. Greg Dickman, a grower in Auburn, Indiana, stores his inventory of 700,000
bees in a 12 x 12 shed over winter. One wall of the shed holds all the bees (Rollie, 1997).
Brian Griffin also recommends placing the nests in a paper bag along with a moist paper
towel, to reduce dehydration (Brian, 1993). Indoor storage reduces the likelihood of predation and also allows the grower to control the time of emergence. In this case, the
nests should not be placed in storage until September or October (Ron and Klostermeyer,
1981). Then, allow about 3 days of at least 50°F weather, and the bees will begin to
emerge.
Osmia lignaria (commonly called the orchard mason bee, blue orchard bee, mason
bee, or orchard bee) is a pollinator of many fruit crops, including almond, apple, cherry,
pear, and plum (Torchio, 1990). The orchard mason bee (OMB) is a native, solitary bee,
slightly smaller than a honeybee and is shiny dark blue. They are non-aggressive and
rarely sting. One only needs 250-750 orchard mason bees to pollinate an acre of apples.
It would take 60,000-120,000 honeybees to cover the same area.
Osmia cornifrons (the horned-faced or hornfaced bee) is a commercial pollinator of
apples in Japan and is a pollinator of rchard crops grown in areas of higher humidities in
the U.S. (Torchio, 1990). The hornfaced bee is 80 times more effective than honeybees
for pollinating apples (Rollie, 1997). A single hornfaced bee can visit 15 flowers a minute,
setting 2,450 apples in a day, compared to the 50 flowers set in a honeybee's day. In
Japan, where hornfaced bees pollinate up to 30 per cent of the country's apple crop
(Rollie,1997), apple growers need only about 500 to 600 hornfaced bees per hectare
(2.47 acres) (Rieckenberg, 1994). Osmia ribifloris (sometimes called the blueberry bee)
has been used successfully as a highly effective and manageable pollinator of highbush
blueberry (Torchio, 1990). This bee, native to the western U.S., pollinates blueberries
three times faster than a honey bee (Wright, 1997). Only 300 Osmia ribifloris are needed
to pollinate an acre of blueberries (Rieckenberg, 1994).
Stingless bees ( Trigona spp.)
These bees are found in the holes of tree trunks (Michener, 1974 , Roubik,1995).
Over 130 species of stinglees bees world over have been identified as potential pollinators of crop and can be managed for this purpose (Roubik,1995). Only the non-infurious
species are managed e.g. 40 species of Trigona, 40 species Scaptotrigona , 4 species
Cepholotrigona and Melipona can utilize artificial domiciles and can be kept in hives.
Trigona may nest in hollows of varied habitats whereas, Cephalotrigona and Melipona
can be managed in section of tree trunks close to their forest habitat. Most of the spe18
cies which can be managed are distributed in tropical America and Asia. The size of the
nest may vary from 3-30 cm.
Stingless bees possess many characteristics that enhance their importance as crop
pollinators like perenniality, polylecty, floral constancy, recruitment, harmlessness and
resistant to diseases and parasites of honey bees suit them for pollination.
Shaggy Fuzzyfoot Bees ( Anthophora pilipes )
The shaggy fuzzyfoot bee is a fat, shaggy, fastflying bee that buzz-pollinates blueberries. In this type of pollination, the bee creates a vibration that releases the pollen
from inside tiny, tubelike anthers. Shaggy fuzzyfoots pollinate in the rain. They pollinate
blueberries, apples, and other crops for about 6 weeks in the spring. During this time,
females lay eggs in mud cells. Bee larvae grow inside them during the summer, pupate
in the fall, become adults,and hibernate in the cells over winter. They are best adapted
to a moist, warm climate and can survive mild winters (Rieckenberg, 1994).
Flies (Diptera)
More than 550 species of flowering plants are visited by Diptera (Larson et al. ,2001)
that are potential pollinators. Mostly, they pollinate and visit plants such as mango,
onion, coriander, fennel, capsicum and carrot.The important species are Episyrphus
balteatus, Eristalis tenax, Ischiodan scutellaris, Betasyrphus serarius and Metasyrphus
confrator.
Other Pollinators
The bees listed above are by no means inclusive of all available pollinators. Other
candidates among the native bees include sunflower bees (Eumegachile pugnata ) and
blueberry bees (Habropoda laboriosa ) (Keven et. al., 1998). Beetles, butterflies and moths
can also be good pollinators.
Suggested Readings
Smith-Heavenrich, Hue. 1998. Going native with pollinators. Maine Organic Farmer &
Gardener (3 & 5) : 16-17.
Free, J. B. 1993. Insect Pollination of Crops (2nd Ed.). Academic Press, New York.
Torchio, P. F. 1990. Diversification of pollination strategies for U.S. crops. Enviornmental
Entomology 19 (6) :1649-1656.
19
POLLINATION SYNDROME IN RELATION TO
INSECT POLLINATORS
SunitaYadav and H. D. Kaushik
Project Coordinator Unit, AICRP on Honey Bees and Pollinators,
CCS Haryana Agricultural University, Hisar 125 004, Haryana
The existence of pollination syndromes supposedly reflects a process of convergent
evolution (Fægri and Van der Pijl 1979) in which plants that share pollinators or that
have pollinators with similar morphology and behaviour, are subject to similar selective
pressures and end up having similar phenotypic traits. "Syndrome" by itself means "a
number of characteristics or features that seem to go with each other or are believed to
be connected in some way". Thus pollination syndromes can be defined as "suites of
phenotypic traits hypothesized to reflect convergent adaptations of flowers for pollination by specific types of animals". The classical pollination syndromes have roots in the
writings of Federico Delpino (1873-1874), who proposed two distinct schemes for categorizing flowers according to traits such as shape, colour, scent and size. His work
was modified over subsequent decades by other workers. These early contributions, and
more recent ones, including those of Vogel (1954) and further modified by Van der Pijl
(1960) and Faegri and Van der Pijl (1979) had led to the modern articulations of the
pollination syndromes in which various pollination syndromes are named after their main
pollinator taxon. The traits that flowers exhibit are in a state of continuous change as
both flower and pollinator adapt to take better advantage of each other. Infact the syndromes have played a central role in the development of pollination biology (Willmer,
2011).Flowering plants have evolved two types of pollination syndromes based on pollinating agents: 1) pollination without the involvement of organisms (abiotic), and 2) pollination mediated by animals (biotic).
A) Abiotic Pollination Syndrome
The movement of pollen grains from one plant to another without the help of animal
vector is termed as abiotic pollination. This is very uncommon method of pollination.
Only 20 per cent of pollination is carried out through abiotic agents. With few exceptions
it is a wasteful process as pollen transfer is non-directional. This type of pollination is
seen in different grasses, majority of the coniferous trees and deciduous trees. Abiotic
pollinating agents are wind, water, and gravity.
1. Gravity pollination (Geophily)
Geophily is highly unreliable, rare and insignificant kind of pollination (Sihag and
Kaur, 1997). It is found in self-pollinated crop plants. In this case, pollen falls because of
gravity on to receptive stigma of other flowers. This may also takes place when a deciduous corolla slides past the stigma.
2. Wind pollination (Anemophily)
In anemophily pollen is distributed by wind. It is a passive process. It is the
20
dominant type of abiotic pollination found both in gymnosperms (non-flowering) and
angiosperms (flower-producing). Though most of the grasses are self-pollinated, but any
cross-pollination that occurs is usually caused by wind or gravity. The other common
examples of wind pollinated plants are corn, sugarcane, rice, coconut palm, sedges,
bamboo, etc. Characteristics of wind-pollinated flowers are: i) Flowers are usually small,
green or dull-colored and scentless and thus not attractive to insects ii) Calyx and corolla are either reduced or absent iii) They do not produce nectar iv) Pollen is abundant
as wastage is higher v) Pollen grains are small, dry, smooth and light so that they are
buoyant and easily blown about by air currents vi) Pollen produced by these plants is of
very low nutritional benefit to insects, having low protein content, and usually will only
be gathered by them when other pollen sources are scarce vii) Male and female reproductive organs are generally found in separate flowers viii) The stamens dangle from the
flower so that a breeze can dislodge pollen easily ix) Stigmas protrude and are large,
feathery and sticky so that they provide a large surface area to catch pollen floating in
the air x) Nectar guides are absent xi) In many wind-pollinated angiosperms, each flower
has only a few ovules, and often only one of them produces a seed.
3. Water pollination (Hydrophily)
The transfer of pollen grains from anther to stigma through the agency of water is
called hydrophily. It is a fairly uncommon form of pollination. Hydrophily does not occur
in all aquatic plants. Many aquatic plants bear their flowers above the surface of water
and are pollinated by wind or insects.
B) Biotic Pollination Syndromes (Zoophily)
The general syndrome of biotic pollination is that the flowers produce a primary
attractant (pollen and nectar) and secondary attractant (odour, colour, shape, size, floral density etc.) that attract pollinators.
Primary Attractant :
i) Nectar : While pollen plays an important role in the sexual reproduction of
angiosperms, nectar acts as a mere attractant. The very purpose of its production is to
allure the pollinators to accomplish pollination. Nectar is secreted from specialized regions or organs of the flower called nectaries. There may be floral or extra-floral nectaries. Floral nectaries may be located within the gynoecium (e.g. the "septal" nectaries
of many monocots) on the perianth or at the base of and often surrounding the gynoecium or androecium.
ii) Pollen : Another pollination reward is pollen itself which is a relatively rich source of
proteins. Pollen forms the part of brood food for many insects e.g. bees. It is also a part
of food for some adult insects e.g. beetles and bats. Pollen attraction is more selective
as it is generally well exposed and available to the visitors. However, in situations, where
nectar is the chief attractant for effective pollination, pollen availability must synchronize with nectar availability. Secondary modification associated with pollen is the presence of specific pollen odor. Insects have their own preferences for pollen odor also. In
21
honeybees, one individual, at a time, will collect the pollen or nectar of only one type
(preferred type first) and only pollen/nectar in a visit while bumble bees collect both
pollen and nectar during the same visit by going through different movements, twisting
their bodies round the anthers e.g. Bombus agrorum . In some bees, pollen is collected
in the crop and is regurgitated again. But in most bees pollen is carried between stiff
hairs, which may be found either on the abdomen e.g. in Megachile ; or on the legs
forming corbiculae as in Apis species.
Some flowering plants produce waxes (e.g. Krameria ) or resins (e.g. Clusia ) as a
primary attractant/reward. Finally in some rare cases, insect may obtain specific chemical compounds that are used to attract a male.
Secondary Attractant : The secondary attractants e.g. odour, colour, shape, or
texture actually advertises the presence of the reward.
i) Flower colour : A visual attractant is usually a showy perianth that may be brightly
coloured or otherwise contrasting with the external environment e.g. a white perianth at
night. Other floral parts such as stamens (e.g. Hibiscus ), staminodes (e.g. members of
the Azioaceae, Cannaceae ), corona (e.g. Crinum, Narcissus, Passiflora ), or even the
gynoecium, may replace or augment the perianth as a visual attractant. Individual
flowers may actually be small, but the accumulation of flowers as an inflorescence may
provide a significant visual attractant.
ii) Flower odour : Olfactory attractants include the volatile compounds emitted by
flowers, usually from the surface of the perianth. Most odoriferous flowers have a sweetish smell (e.g. Jasminum ), but other emits compounds that mimic the smell of rotting
flesh (e.g. Aristolochia, Arum, Stapelia )
iii) Flower shape and size : Large sized blossoms are normally pollinated by large
sized pollinators and vice-versa. To attract large sized pollinators, however, some small
sized blossoms have undergone modification to provide a platform or ball type inflorescence e.g. cythium in compositae, umbelliferae and apparent umbel inflorescence of
Allium cepa . Perianth constitutes the advertising organ of the blossom. Floral shape and
size act as the proximate as well as ultimate factors for flowers and pollinators.
Flowers come in many different shapes, which determine the type of pollinator
attracted by them.
a . Saucer or bowl-shaped flowers : These are more complex flowers which are pollinated by bees. Examples: Morning glories, lily of the valley, chives, nasturtium,
campanula
b . Tube flowers : These flowers must be visited by pollinators with long tongue, such
as bees, butterflies, moths, and humming birds in order to be fertilized. All mint
flowers are tube-shaped. Examples: Mints, cardinal flower, phlox, primroses, trumpet creeper
c. Pea or bean-type flowers : These flowers are considered a form of tube flower.
They always have an upper petal called a standard , a lower petal called a keel, and
22
two petals on each side of the keel called wings. If you open the wings you can see
the stamens and pistil of the flower. These flowers are usually visited by bees and
honeybees. Examples: sweet pea, clovers, alfalfa etc.
d . Composite flowers : These flowers are made up of a few to hundreds of smaller,
individual florets called "disk flowers" in the center and the petal-like "ray flowers"
around the edges. Many composites bloom from the outside of the disk to the inside. The individual flowers mature at different rates, so outer flowers have mature
pistils and the inner flowers have mature stamens. When a bee visits a flower, she
gets pollen on her body from the inner flowers which she then deposits on the pistils
of the next flower.
e . Closed flowers : These flowers have such tightly closed petals they are pollinated
by only large, strong, intelligent insects such as bumblebees which are able to force
their way into them. Examples: some gentians, turtlehead, toadflax.
f.
Trap flowers : These flowers are "sneaky," they trap insects inside them until pollination occurs. Milkweeds are interesting flowers in that they catch insects' legs in
little slits which contain the V-shaped pollen-bearing pollinia. Some weaker insects,
such as soldier beetles, are unable to escape from the slits and they die. Examples:
some orchids, Dutchman's-pipe
The biotic pollinating syndromes is described under two headings namely invertebrate and vertebrate pollinators.
I)
Invertebrate pollinators
Among invertebrates, insects are the major biotic pollinators of flowers and are responsible for up to 80% pollination of crops. Following types of pollination is brought
out by the invertebrates.
Insect Pollination (Entomophily)
The flowers do not tend to have any common characteristics because many different
types of insects have very different ways of pollinating flowers. In insect pollinated plants,
mostly pollen is dry while stigma is viscid. When any pollinator touches the latter some
mucous is transferred to its body. When this pollinator visits next flower, the pollen gets
adhered to its body and will be carried to next stigma where it will be shed off e.g. in
orchids, Montrapa etc. The various insect pollinators are ants, bees (honey bees and
other colonial bees, gregarious and solitary bees), beetles, butterflies, flies, moths and
wasps. The bees are by far the most important among insects.
Some of the characteristic features of insect pollinated flowers are
The flowers are large, conspicuous and brightly coloured.
When flowers are small, they aggregate in the form of inflorescence.
The flowers have a pleasant fragrance and sweet nectar.
Pollen grains are usually rough and sticky and often show spinous outgrowths.
23
Bee pollination (Melittophily)
Bees are the most versatile, the most active, and consequently, the best-known
pollinators of several plants and are best adapted for various blossoms and floral structures. Michener (2000) remarked that bees with about 17,000 known species are the
world's dominant pollinators; whereas Buchmann and Ascher (2005) affirm that bee species collectively pollinate the 250,000 known angiosperm species.
Wasp pollination (Sphecophily)
They are unsteady pollinators. In general, wasps are of little significance as pollinator. Their pollination ecology includes: no brood management, primitive mouth parts,
tongue usually small (1-3 mm), flat and can be used for lapping nectar only (with some
exceptions). Their body is sparsely covered with coarse spines, not adapted to the
transfer of pollen as are the hairs of bees.
Butterfly pollination (Psychophily)
Butterflies are diurnal and have good vision (can see red) but a weak sense of smell.
They are perching feeders. Highly perched on their long thin legs, they do not pick up
much pollen on their bodies and lack specialized structures for collecting it. Butterflies
walk around on flower clusters probing the blossoms with their tongues. Possession of
a long proboscis in butterflies allows them to access nectar from narrow tubular corollas, in addition to those with more exposed nectar.
Moth pollination (Phalaenophily)
Moths are nocturnal, have a strong sense of olfaction, and are active fliers, hover in
front of flowers but not land on them. Moth-pollinated flowers tend to be white, nightopening, large and showy with tubular corollas and a strong, sweet scent produced in
the evening, night or early morning. The petals are flat or bent back (recurved) so the
moth can get in. Ample nectar is produced by them, with nectaries deeply hidden, such
as morning glory, tobacco, yucca, and gardenia. The yucca plant is dependent upon the
tiny yucca moth for cross pollination.
Hawk moths (Sphingidae) have especially long tongues and can pollinate tropical
flowers with the corolla tube up to ten inches long. Hawk Moths hover in front of flowers
with rapid wing beats and a lot of nectar is produced to fuel the high metabolic rates
needed to power their flight.
Fly pollination (Myophily)
Flies are considered to be less important, ineffective and unreliable pollinators but
their sheer numbers and the presence of some flies throughout the year make them
important pollinators of some temperate and many tropical flowering plants. Flies are
also important pollinators in high-altitude and high-latitude systems, where they are
numerous and other insect groups are lacking. Flies generally visit flowers that smell
foul, often with scents of decaying meat or feces. Some flies feed on nectar and pollen
as adults e.g. bee flies (Bombyliidae), hoverflies (Syrphidae), etc. These regularly visit
24
flowers. On the other hand, male fruit flies (Tephritidae) are attracted to and feed on
specific floral attractant (which acts as fly's sex pheromone precursor or booster) of
some wild orchids (Bulbophyllum species) that do not produce nectar. Myophilous plants
are purple, violet, blue, and white coloured: open dishes or tubes and includes nectar
guides but have no scent.
Carrion and dung fly pollination (Sapromyophily)
Sapromyophiles, normally visit dead animals or dung but sometimes adult females
seeking for a site to lay her eggs get attracted to flowers that mimic these odoriferous
items and lay eggs inside so that after hatching larvae can feed on animal-originated
material. However this "resource", in fact, does not exist in the flower and pollination
occurs by allurement and deception. After the hatching of the eggs the larvae starve to
death. It is mainly performed by carrion flies and occurs in flowers which are brown or
orange in color and have a strong, unpleasant odor. This group includes the Araceae
family, which produces highly modified flowers.
Beetle pollination (Cantharophily)
Beetles were among the first insects to visit flowers and they remain essential pollinators today. They comprise the largest set of pollinating animals, due to sheer numbers. They are responsible for pollinating 88 per cent of the 240,000 flowering plants
globally. Cantharophily, is somewhat rare in temperate areas, but is quite common in
the tropical zone. Some beetles have evolved the pollen eating habit. Beetle-pollinated
flowers are usually large, greenish or off-white in color and heavily scented as beetles
rely on their sense of smell for feeding and finding a place to lay their eggs. Scents
associated with beetle pollination are often spicy (Crab apples), sweet (Chimonananthus),
or fermented (Calycanthus ).
Ant Pollination (Myrmecophily)
Myrmecophiles (Armstrong, 1979; Wyatt, 1981) form a great group of social insects
that are often observed visiting flowers to collect energy rich nectar. Ants are gregarious
and visit extra-floral nectarines in groups. They are wingless and must crawl into each
flower to reach their reward. They mostly take nectar without effectively cross-pollinating flowers. Ants visit inconspicuous, low-growing flowers positioned close to the stem.
Many tropical plants have floral structures that make it difficult for bees and other pollinators to access internal nectar. Thus, it is tempting for such insects to simply pierce
the flowers from the outside. But ants feeding on the nectar secreted outside of the
flower prevent these insects from robbing nectar and thus forcing them to enter the
flower in a way that is more conducive to pollination.
Thrip pollination (Thripsophily)
Thrips are mainly considered as phytophagous insect pests. While demonstrating
the significance of change in the colour of an inflorescence of a particular variety of
Lantana camera , Mathur and Mohan Ram, 1978 established the role of thrips in pollination. Several instances of thrip pollination has been reported from the members of
25
Asteraceae, Solanaceae and Fabaceae reaching to the conclusion that thripophily (Kirk
1988) is a common phenomenon in nectar producing flowers. Pollination in Erica tetralix
and Calluna vulgaris by Taeniothrips ericae and Frankliniella intosa were also reported
by Hagerup (1950) and Hagerup & Hagerup (1953).
Slug pollination (Malacophily)
The cross pollination that is favoured by slugs is called malacophily. Snails and
slugs are herbivores that feed on soft vegetation and are most unlikely to be considered
as pollinators. Some flowers, however, would not attract flying pollinators because they
are so close to the ground and are covered by leaf litter. It is believed that slugs or snails
may pollinate these flowers e.g. wild ginger.
II) Vertebrates as pollinators
Although vertebrate pollinators are not as common as insect pollinators, they do
exist, and include birds and mammals. Compared with most insects, flower-visiting birds
and bats are much larger, have greater energy requirements, can carry larger pollen
loads and are longer-lived. Despite the potentially greater costs to plants to attract and
reward these larger pollinators, the benefits of vertebrate pollination can be substantial,
especially in habitats where insect activity is limited by harsh climatic conditions (e.g.
on tropical mountains; Cruden, 1972). Compared with many insects, birds and bats are
excellent in promoting out crossing and as a result, most vertebrate-pollinated plants
have hermaphroditic breeding systems; very few are dioecious. Besides birds and bats,
some squirrels, tree-shrews and lower primates also help to accomplish pollination of
flowers.
Bird pollination (Ornithophily)
It is a mode of pollination performed by birds. The most common bird pollinators are
sun bird, humming bird, crow, bulbul, parrot, mynah, etc. They visit flowers for the sake
of nectar or insects. Pollinating birds are diurnal in their activity, and have long tongue
and bill. They have visual sensitivity for red colour but not for ultra violet reflectance. In
general, they lack sense of smell. Still they can efficiently locate the path to nectar
which they consume in bulks. The flowers that are visited by birds and hummingbirds
are both tubular and disc shaped and has petals that are recurved to be out of the way.
The flowers pollinated by birds are brightly coloured (red, yellow, or orange), odourless,
secrete copius amount of concealed nectar and are modest pollen producers that are
designed to dust on the head or beak of the bird, as it probes the flower for nectar.
Bat pollination (Chiropterophily)
Bat pollination is an integral process in tropical communities with 500 tropical plant
species completely, or partially, dependent on bats for pollination (Heithaus, 1974). Most
flower visiting bats are found in Africa, Southeast Asia, and the Pacific Islands. They
provide two important benefits to plants: i) they deposit large amounts of pollen ii) disperse pollen to long-distances. Bats are nocturnal with a good sense of smell, good
vision and a long, bristly tongue.
26
Pekkarinen (1998) described the relationship between a pollinator and a floral
species on the basis of foraging behavior and classified them into polylectic, oligolectic
and monolectic pollinators.
i) Polylectic pollinators : A pollinator that forages on a wide variety of flower species
is considered polylectic. Most pollinator species, including the honey bee (Apis mellifera ),
bumble bee species (e.g., Bombus terrestris, Bombus pascuorum and Bombus lapidarie ),
a few solitary bees and several butterfly species, fall into this category.
ii) Oligolectic pollinators : A pollinator that visits, two to several species in one plant
family is considered oligolectic. Very few species fall into this category although many
solitary bees are oligolectic; namely, Bombus gerstaeckeri , which forages exclusively
in species belonging to the genus Aconitum (Poncheau et al., 2006). An oligolectic
pollinator will continue to forage in a single plant species even though other pollen
resources may be available (Waser, 1983).
iii) Monolectic pollinators : Monolectic species have the most restricted floral requirements, feeding on only a single plant species, even when other species in the
same genus are present. Monolectism is even rarer by far than oligolectism. It may be
observed in orchid-pollinating Hymenoptera, in the yucca-pollinating butterfly and in small
fig tree-pollinating wasps. The leafcutting bee Hoplitisa dunce forages only in flowers of
the common blueweed, the melittid bee, Macropis fulvipesselects exclusively garden
loosestrife flowers and Micropteryx calthella , a small nocturnal butterfly, forages only in
buttercup flowers.
It should be pointed out that a species may be oligolectic in its search for pollen but
polylectic when looking for nectar. A flower is considered oligophilic, polyphilic or
monophilic on the basis of its pollination by an oligolectic, polylectic or monolectic
species.
Suggested Readings
Ackerman, J. D. 2000. Abiotic pollen and pollination: ecological, functional, and evolutionary perspectives. Plant Syst. Evol. 222 : 167-185.
Buchmann, S. L. and Ascher J. S. 2005.The Plight of Pollinating Bees. Bee World
86 : 71-74.
Faegri, K. and van der pijl, L. 1979. The principles of pollination ecology. 3rd edition.
Pergamon Press, Oxford, U.K.
Michener, C. D. 2007. The floral relationship of bees . Pp. 13-18. In: The Bees of The
World. John Hopkins university press, Baltimore, Maryland, London.
Muchhala, N. 2003. Exploring the boundary between pollination syndromes: bats and
hummingbirds as pollinators of Burmeistera cyclostigmata and B. tenuiflora
(Campanulaceae). Oecologia 134 : 373-380.
Sihag, R. C. and Kaur, G. 1997. Pollination maechanisms and syndromes. In : Pollination Biology, Basic and Applied Principles (Ed Sihag R.C.). Rajendra Scientific
Publishers, Hisar. Pp 19-38.
27
HABITAT MANAGEMENT FOR SUSTAINABILITY OF POLLINATORS
Pala Ram
Department of Entomology
CCS Haryana Agricultural University, Hisar 125 004
Pollination by insects has a direct impact on the evolution of flora and fauna. It is
assumed that grasses and all other angiosperms arose from plants dependent upon
insects for pollination. Therefore, evolution of mammals without angiosperms would
certainly have been different. Similarly, some of several insects like beetles, wasps,
flies, butterflies and moths, rodents, herbivores and primates are dependent upon the
products provided by flowers. Thus, insect pollination was necessary to the development of angiosperms and angiosperms were important in the evolution of human beings.
Keeping this in view, one can imagine grave consequences for the flora and fauna if
pollinating insects become extinct.
Plant pollination by animals is essential for agricultural production, agro-ecosystem
diversity and biodiversity. Bees are the most important commercial pollinators (Michener,
2000) but native pollinator communities are comprised of birds, bats, bees, wasps, beetles,
flies, butterflies and moths (Barth, 1985). Over 75 per cent of world's most commonly
cultivated crops and 80 per cent of all flowering plant species rely on animal pollinators,
mostly insects, for pollination (Nabhan and Buchmann, 1997; Kremen et al. , 2007).
About 35 per cent of world's crop production is dependent on pollination by animals
(Klein et al. , 2006). Agriculture production, agro-ecosystem diversity and biodiversity
are being threatened by declining pollinator populations. Basu et al. (2011) analyzed
yields of vegetable crops in India over 45 years (1963-2008) using FAO data, by using a
method that partitions crops into categories depending on their relative pollinator dependence, found that since 1993, relative yields of crops have either flattened or declined,
while pollinator non-dependent crops show no similar decline.
Some contributing factors to declining pollinator populations include habitat loss or
fragmentation due to increasing urbanization, the destruction of natural
host plants, land management practices involving drainage, tillage, irrigation, clean cultivation, intensive agriculture, climate change, the use of insecticides and herbicides on
blooming plants, parasites and diseases, alien plant species, etc. The present review
will throw some light on how to enhance habitat for native pollinators, how to
provide habitat resources and how to alter specific farm practices to reduce impacts on
pollinators.
Habitat site selection
Researches have shown that pollinator habitats at a half-mile distance from fields
result in greater number and diversity of native pollinators as well as increased pollination. Therefore, untilled areas such as stream banks, utility easements, and unused
land around farm buildings and service areas within half-mile from field edges can serve
28
as nest sites and for foraging as needed by pollinators. These sites have relatively stable
conditions and will allow permanent establishment of nests and pollinator-friendly plants.
Similarly, peripheral areas such as field edges, fencerows, hedgerows, road edges etc.
can offer both nesting and foraging sites. Habitat for any species of bee must consist of
rewarding patches of floral resources and suitable nesting sites, all within flight range of
each other. For butterflies and moths, the minimum requirements for habitat must include larval food plants as well as adult food resources. Larval hosts and habitats must
also be considered for other invertebrate floral visitors, such as flies and beetles.
Suitable nesting substrates for bees vary with species, and may include holes of
appropriate diameter left by wood-boring beetles, tree cavities, pithy or hollow plant
stems of the correct diameter, abandoned rodent burrows, or soils of suitable texture,
depth, slope, vegetation cover, and moisture. Following conservation practices can result in the establishment of pollinating insects' populations.
Providing nesting sites, nesting materials and egg-laying sites
Bumble bees and other native bees prefer to dig nest in the ground in well-insulated
cavities, many excavate tunnels in bare soil, others occupy tree cavities and a few even
chew out soft pith of stems of plants to make nests. Bumble bees are usually considered social and make their nests in abandoned rodent burrows. Most of the bee species
are ground-nesters and are solitary, with one female excavating and provisioning her
own nest. Therefore, providing undisturbed grassy areas around fields may provide suitable underground nesting sites. Bees often nest on southern exposed banks to maximize exposure of nest sites to solar radiation. Batra (2001) proposed the term "bee
zone" to describe an area that can be maintained by a grower for native bees nesting.
The growers should maintain permanent strips of land along the southern side of their
farm. Bees often prefer sandy loam banks for nesting. Well drained soil nesting banks
may be constructed. The banks should be 1 to 2 m high, 2 to 3 m wide and 3 m or more
long (Batra, 2001). Tilling and flood irrigation of bare areas should be avoided in order to
protect nesting sites of ground-nesting bees (Shuler et al. , 2005; Vaughan et al., 2007).
Similarly application of soil pesticides, spray of herbicides and grazing in bare areas
should be avoided to protect ground nesting bees and other pollinators.
Mason bees and leafcutter bees make nests in hollow plant stems and providing
holes drilled into wooden blocks or bundles of cut plant stems can provide the necessary nesting sites that cavity-nesting bees require. Therefore, allowing dead trees to
stand as long as they do not pose any risk to people and property will go a long way in
supporting the cavity-nesting bees. Bees also use plant material for building and provisioning their nests (Krombein, 1967). Leafcutter bees remove circular pieces of leaf and
use them to line their nests. Mason bees and leafcutter bees build their nests in cavities
using soil or leaf material to separate the individual cells. Some wood-nesters also use
materials such as mud, leaf pieces, or tree resin to construct brood cells in their nests.
Thus, providing appropriate materials nearby can help make it easier for bees to build
their nests.
Moths and butterflies lay their eggs on or near plants on which their young ones will
29
feed after hatching. Therefore, for conserving butterflies and moths, caterpillar host plants
are necessary. While planting host plants it should also be kept in mind that some
butterflies like monarch butterfly are monophagous while others like swallowtails are
polyphagous. Thus, a variety of host plants should be grown so that these can be used
by a large number of species. For encouraging syrphid fly population, habitat should
have aphids for immatures and flowers for nectar-feeding adults. Larvae of other pollinating flies are parasitic, predatory or saprophytic depending upon the species. Similarly,
the grubs of beetle feed on a variety of foods. Therefore, for conserving pollinating beetles
a variety of host plant species should be grown so that both herbivorous and insectivorous beetles can be conserved.
Providing nectar and pollen sources
Some pollinators feed on nectar while others on pollen. Many pollinators are active
throughout the crop growing season. So, when a crop that needs pollination is not in
bloom, the pollinators still need to feed themselves and their young ones. Most pollinators search for nectar and pollen within close range of their nest. Therefore, in order to
conserve an abundance of diverse pollinators, the habitat should be rich in flowering
plant species that should bloom through a long season. Early-flowering plants would
feed pollinators emerging from hibernation while late-flowering plants would help them
build-up their energy reserves before going into hibernation (Pywell et al ., 2005). The
growers should assess the nectar and pollen sources by looking at all the potential
plants grown on and around his farm and by observing the pollinators visiting these
flowers. These plants may be crops or weed plants grown on fallow lands along roadsides, fallow fields, hedgerows, buffer areas and other vegetation areas.
Depending upon the body size and morphology (tongue length), some pollinators
can reach the pollen and nectar in flowers of certain species while other pollinators in
flowers of other plant species. Therefore, in order to conserve a diverse community of
pollinators, a diverse array of flower sources is required. Simple methods to increase
the abundance and diversity of flowering plants are to leave undisturbed, herbicide-free
strips of land or to disturb a strip of soil to encourage germination of annual and perennial flowering plants. These flowering areas can be managed to keep them contained
and to stop their flowering during the bloom period of the adjacent crop. As long as a
weed plant in not noxious growers may allow the plant to bloom, mow them during crop
bloom and let them bloom again afterward. Fallow pieces of land can also be planted
with wildflower mixes for supporting pollinators. By growing diverse species of plants,
farmers may provide pollen and nectar sources throughout the year. Such habitat can
take form of "an ideal pollinator habitat" which will reduce the foraging distance which
pollinators travel to find pollen, nectar and nesting resources (Fig. 1). Such habitat will
also ensure food for caterpillars of moths, butterflies and other foliage feeders. The size
of such habitats should be at least 6000 sq. meters and above (Morandin and Winston,
2006). In case of small land holdings a group of growers collectively can maintain such
a habitat.
30
Fig. 1. An ideal pollinator habitat (Source : USDA National Agro-forestry Centre)
Using pesticides judiciously
The insecticides not only directly kill bees, but also cause indirect sub-lethal effects
such as reduced fecundity and abnormal foraging behaviour, increase in immunological
disorder, and a decrease in learning ability (Desneux et al., 2007). Insecticides that are
highly toxic to bees and have a residual period longer than eight hours are responsible
for most of the bee poisoning incidents. Insecticides responsible for bee poisoning are
organophosphates (e.g. acephate, chlorpyriphos, malathion, methyl parathion), carbamates (like carbryl, carbafuran) and neonicotinoids (such as clothianidin, imidacloprid,
thiamethoxam). Similarly many pyrethroids are also highly toxic to bees.
Most bee poisoning incidents occur when insecticides are applied to bee-pollinated
crops. Insecticide applications should be avoided during bloom to minimize insecticide
poisoning. In situations where insecticides must be used, it is best to avoid spraying
when flowers are in bloom or when pollinators are least active. Selecting least toxic
insecticides for application during other times of the growing season when bees may be
exposed should lessen the impact of the insecticide application. Non-toxic or slightly
toxic insecticides to honeybees are Bacillus thuringiensis (Dipel), tefubenoxide
(Confirm) and neem (Azadirect) (Drummond and Stubbs, 2003). Residual pesticides,
such as organophosphates can contaminate pollen and nectar and are taken back to the
hive or nest by the foraging bee. This contaminated food then kills the brood (Atkins,
1992). If highly toxic insecticides are used, then caution should be taken to spray on
calm days to minimize drift and in the evening when bee activity is lower and exposure is
lessened. In general dusts and microencapsulated insecticides are the most dangerous
formulations for bees, and aerial spraying is the most harmful method of application.
Thus, selecting less harmful formulations like granules will conserve pollinators.
Herbicides which are considered relatively nontoxic to honeybees can have an
indirect effect on native bee communities by reducing the amount of nectar and pollen
available by killing wild flowering plants and by displacing nectar and pollen-rich plants
by herbicide-tolerant plants that are not rich resources for bees (Atkins, 1992). Some
herbicides like organic arsenicals and phenoxy materials can have lethal effects in
bees. In some circumstances, herbicides appear to have a greater effect on wild bee
populations than insecticides by resulting in decline of suitable nesting sites and
alternate food plants.
31
Managing grazing, mowing and fire
Grazing, fire, and mowing can have damaging impacts on pollinators but can be
used carefully in a manner that benefits pollinators. Grazing is a common practice in
rangelands and can have severe ecological impacts if not properly managed. Not much
work has been done on the effect of grazing on the population of pollinators. However,
some studies show that excessive sheep grazing can result in removal of enough flowering plants resulting in elimination of bumble bees (Hatfield and LeBuhn, 2007) and larval
mortality in butterflies by destroying host plants (Smallidge and Leopold, 1997). Thus
grazing should be avoided when butterfly larvae or adults are active as it can result in
direct mortality. Grazing can harm pollinators by destroying potential nest sites and
existing nests, by removal of food sources and by directly trampling of adult pollinators.
In a study conducted by Debano (2006) it has been found that invertebrate species
richness, abundance and diversity are greater in ungrazed areas. Only a portion of habitat should be grazed at any one time in order to protect overwintering pollinators and
foraging larvae and adults so that the disturbed area can be recolonized from the nearby
undisturbed refuge (Black et al. , 2008).
Mowing is usually done in place of grazing to alter grassland succession and species composition by suppressing growth of vegetation at those sites which permit equipment access. Mowing can cause direct mortality of egg, larval and pupal stages of the
pollinators. Mowing can also destroy structural diversity and potential nesting sites by
creating a sward of uniform height. Mowing can also result in sudden removal of almost
all flower resources for foraging pollinators. Therefore, no more than a third of habitat
should be mown in one year in order to protect pollinators and foraging larvae and adults
so that the mown area can be recolonized from the nearby undisturbed refuge. Maintenance activities should be avoided when plants are in flowering stage in order to
maximize foraging and egg-laying activities. Ideally, mowing should be done in the
winter season when there are no flowers. Mowing a mosaic of patches over several years
is better than mowing an entire site all at once and no single area should be mown more
than once a year.
Controlled burning has an important role to play in the long-term maintenance of
pollinator habitat. Fire may benefit pollinators through restoration and maintenance of
suitable habitat if used appropriately (Hartley et al. , 2007). However, prescribed burning
in small fragments, where populations are more isolated, can have deleterious effects
on the population of pollinators due to lack of colonizing capacity. A study conducted by
Neeman et al. (2000) revealed that fruit set was lower in burned area as compared to
unburned area. It has been found that it takes 17-24 years for insect communities in
burned areas to recover to the pre-burn level (Moretti et al. , (2006). Thus in order to
minimize negative impacts, a single fire should not burn an entire area of pollinator
habitat and a programme of rotational burning in which small sections (<30%) of a site
are burned every few years will ensure adequate colonization potential and refugia for
insects.
32
Managing diseases and parasites
Not much work has been done on the effect of diseases on pollinators; however, well
documented work is available on the effect of diseases and parasites on honeybees.
Honey bee colonies, both managed and feral, are being devastated by the external
parasitic mite, Varroa destructor that was introduced to the North American continent.
Similarly, Evans et al. , (2008) found that decline in bumble bee species population in
USA was mainly due to introduced diseases, from commercially reared bees imported
from Europe. The protozoan pathogen, Nosema bombi caused great problems for reared
colonies of the bumble bee, Bombus occidentalis and has lead to the wide scale
declines of native B. occidentalis across the West Coast and also to declines in other
bumble bees in the subgenus Bombus , particularly the eastern species B. affinis . Therefore, commercially reared bumble bees imported for use in glasshouses for pollination in
tomatoes should not be used for open-field pollination.
Suggested readings
Bhattacharya, A. 2010. Conservation of pollinator resources in botanic gardens. Our
Nature 8 : 322-335
Cameron, S. A., Lozier, J. D., Strangeb, J. P., Koch, J. B., Cordes, N., Solter, L. F. and
Griswold, T. L. 2011. Patterns of widespread decline in North American bumble
bees. PNAS, doi:10.1073/pnas.1014743108
Harrison, S. and Bruna, E. 1999. Habitat fragmentation and large-scale conservation:
what do we know for sure? Ecography , 22 : 225-232.
Murren, C. J. 2002. Effects of habitat fragmentation on pollination: pollinators, pollinia
viability and reproductive success. Journal of Ecology , 90 : 100-107.
Potts, S., Biesmeijer, J., Kremen, C., Neumann, P., Schweiger, O., and Kunin, W.
2010. Global pollinator declines: trends, impacts and drivers. Trends in Ecology
& Evolution, DOI : 10.1016/j.tree.2010.01.007.
Rathcke, B. J. and Jules, E. S. 1993. Habitat fragmentation and plant pollinator interactions. Current Science , 65 (3) : 273-277.
Weibull, A. C., Ostman, O. and Granqvist, A. 2003. Species richness in agroecosystems:
the effect of landscape, habitat and farm management. Biodiversity and
Conservation , 12 : 1335-1355.
33
TRENDS IN INSECT POLLINATION OF CROPS
V. C. Kapoor*
Prof. & Head (Retd.), Department of Zoology, PAU, Ludhiana
Insect pollination is a natural process and continues uninterrupted unless there is
disturbance in its environment. It is the greatest gift of nature. It is known to many that
insects and other animals are involved in pollination but still it is not considered important. Loss of natural service can have a long-term impact on the farming sector which
accounts for about a fifth of the nation's gdp. Both the main components of biodiversity
(plants and animals) are involved in bringing about pollination. The farmers and general
public still do not give much importance to it. They depend mainly on other agricultural
practices for enhancing the crop yield. They are happy when the yield is good but if the
yield is poor, agricultural scientists are blamed. They will never consider the pollination
failure as the cause. The declining agricultural productivity can be attributed to a
number of factors but pollination plays a crucial role. If you have any trouble with your
vegetable and fruit plants failing to reproduce, chances are that what your plants are
lacking are pollinators. One can use all good agricultural practices but without pollination no seed or fruit would be produced. There is close relationship between pollenizers
(plants giving nectar and pollen), insects and crop production. The importance of insect
pollination to agriculture is unequivocal. This process is many times adversely affected
due to natural calamities and human activities.
Due to ever rising human population, there is tremendous pressure on earth for
more food and shelter. Both these requirements are directly connected with changes in
land use resulting in fragmentation of habitats. The extensive and indiscriminate use of
pesticides and chemical fertilizers further complicates this problem. This results in degradation of our environment. The population of insect pollinators declines adveresely
affecting pollination. Thus, there is great need to educate our farmers and general public about the utility of insect pollinators in pollination on which our survival depends. At
places where there is dearth of natural pollinators, the pollination can be made effective
by bringing domestic bees to the crop when it is in bloom. This practice is very much in
use in developed countries for enhancing the quality and quantity of various agricultural
crops. Here, too, this can be encouraged by bringing both the farmers and bee keepers
in close contact for mutual benefit.
Pollination, pollinators and production of crops
This requires the understanding of the following three: taxonmy; biodiversity; and
pollination.
i . Taxonomy : It is concerned with naming of organisms and their relationships with
each other. It thus provides framework for understanding organic diversity in which insect pollinators and plants (pollenizers) are also included. Thus, it is vital for discovering
the biodiversity and its protection. It is only through taxonomy that we can know the
*Present add. : B-904, Wembley Estate, Rosewood City, Sector 49, Sohna Road, Gurgaon 122 018, Haryana
34
different kinds of pollinators present at a given place, their food preference,
seasonal abundance, migration, diseases, parasites, etc. All this is key to managing
the population of pollinators. Even the best known exotic bee species, Apis mellifera ,
was discovered in india by taxonomists. Once we know the identity of pollinators, it
becomes easy to manipulate their use to our best advantage. Here, too, we are facing
with the problem of dearth of taxonomic experts for identification and it is becoming
acute with the passage of time.
ii. Biodiversity : It is full variety of life on earth or totality of different kinds of species
on earth, their forms, etc., of which pollinators are also important part. The understanding of biodiversity is of prime importance for our survival. All components of nature remain in a perfect balance, not only interwoven but also interdependent. The disturbance
to any type of component can threaten the whole life support system of which humanbeings are also important part. Biodiversity depends on taxonomy for discovering the
number of species of plants, animals and microbes existing on earth. It is only after
getting the identity of the organisms that we can know about the status of biodiversity,
i.e., what species are declining and so need protection and what have not been seen
over many years and need to be placed as extinct, and so on. Loss of biodiversity is
irreversible. In 2007, United Nation's Environmental Programme Concept observed that
‘any loss of biodiversity is a matter of public concern, but losses of pollinating insects
may be particularly troublesome because of the potential effects on plant reproduction
and hence food supply security.' thus, pollination and crop production are important
components of biodiversity. Various animal species like bees, butterflies, moths, beetles,
bats, birds, etc. help many flowering plants to reproduce through transportation of
pollen. Pollinator's abundance is linked to productivity. Presently at least one-third of
world's food for humanity is based on this kind of reproduction. Imagine the world without natural fibers, fruits, vegetables, or flowers; that is what our world would be without
pollinators- insects and other animals.
The established biodiversity (pollinators included) is under great threat due to
various factors like population explosion requiring more food and shelter leading to
monoculture of crops and trees, extensive use of agrochemicals, intensive tillage etc.
Moreover, monoculture needs very high populations of bees at bloom. The industrialisation
and urbanisation is done at the cost most valuable wild habitats which are very important for pollinators to survive in the absence of regular hosts. Many pollinators like bats,
butterflies and hummingbirds may migrate many miles during a year. These travelers
need nectar-producing flowers throughout their journeys. Global inventories indicate
that more than one lac animal species play role in pollinating about two and half lac
different kinds of wild flowering plants on this planet. In addition nearly 40,000 species
of bees from the world, wasps, flies, moths, butterflies, beetles and other invertebrates
together with perhaps more than one thousand species of vertebrates like birds and
mammals serve as pollinators. Insect pollination is necessary in the production of most
fruits and vegetables and forage crops required by livestock. It is estimated that more
than thirty genera of animals with hundreds of flower visitors are required to pollinate
nearly one hundred crops that feed the world population.
35
It is, therefore, necessary to protect habitat areas of pollinators so that their number is not declined but continue to increase. When habitats are fragmented into isolated
patches, it is not long when some of the insect or other animal species decline to a
point that they may not be effective to provide ecological service, like pollination, beneficial to plants. Both the pollenizers and pollinators are mutually benefited in the process
of pollination; the formers provide nectar and pollen as food to the latter and the latter
bring about reproduction by transferring the pollens. This process is essential for the
survival of both and hence a key process for healthy functions of world and agricultural
communities and thereby in maintaining the balance in biodiversity.
iii. Pollination : It is the most important component of biodiversity and without which
it is impossible to protect and maintain our rich biodiversity. This fact has also been
recognized by convention of biological diversity, a United Nations' body, came into being
in 1992 with most of the countries as members. This International body coordinates with
the member countries with regard to the development in their respective countries without compromising the already threatened biodiversity. Both the most important components of biodiversity (plants and animals) are involved in this process which allows continuation of the species through reproduction. This reproduction is done through transfer
of pollens from male part of the flower (anther) to the female part (stigma) of same flower
(self fertilization) or another flower of the same plant or another plant of the same
species (cross fertilization). It is difficult to measure the effects of pollinating insects
(mainly bees) on pollination as other agents like wind etc also contribute, sometimes
simultaneously, to pollinate most plants.
Pollination is influenced by two factors : abiotic and biotic. Under abiotic comes
wind, water and gravity; only 20 per cent are pollinated by these factors. The biotic
pollination is done through insects, birds and mammals. Insects are the most dominant
pollinators. Of these bees are most effective in being social and collecting pollen as
food for themselves as well their young ones; their body with hairs helps in transfer of
pollens from one flower to another. Over three-fourth of world's crop and over 80 per cent
of all flowering plants depend on animal pollinators, especially insects. Globally animal contribution of pollinators to the agricultural crops is about 54 billion US$ and world's
15% of hundred principal crops are pollinated by domestic bees (manageable species
like honey bees, bumble bees, alfalfa leaf cutter bees, etc). Seeing the importance of
pollination in food security, United Nations Food and Agricultural Organisation (FAO)
even established the 'International Pollinators Initiative (IPI) with a project involving seven
nations and india is one of them.
Pollination management
It is required as a horticultural practice to accomplish or enhance pollination of a
crop to improve yield and quality by understanding of a particular crop's pollination needs
based on the knowledge of pollenizers, pollinators and pollination conditions.
Pollinators’ decline
Recently, world- wide decline is reported in pollinator's population and diversity. In36
dia is not exception to this problem. This decline is in combination with the alarming
rate of decline seen in our total biodiversity on this planet. This is mainly due to decline
in habitats; decrease in food supply (nectar and pollen) besides increase in monoculture-dominated agriculture with large scale use of chemical fertilizers and pesticides.
This kills large number of our pollinators as well. Air pollution from automobiles and
power plants also inhibit the ability of pollinators like bees and butterflies to find
fragrances of flowers. This decline of our pollinators’ population poses serious threat to
conservation and maintenance of our rich biodiversity. This is the root cause of decrease
in our crop's yield and its quality. Both these are impoortant in the competitive world
market. The decline of pollinators due to above mentioned processes also results in
rapid transfer of pests and diseases to new areas. An example of this is the latest
presence of Varroa mite ( Varroa destructor) attacking the bee species, Apis cerana and
A. mellifera , in Punjab, Haryana, Himachal, Jammu-Kashmir and Rajasthan. It was
reported from a bee colony in Punjab in 2004. This mite sucks haemolymph of the bees
and weakens them; finally leading to collapse of the bee colony. Besides, there are
other pests and diseases of bees which are creating havoc with bee population. The
habitat destruction is going on at an alarming state due to industrialisation, urban and
suburban development required for ever increasing world's human population.
Management of pollinators for improved pollination
The decline in pollinators and their diversity throw big challenge for better managed
pollination to maintain crop yield and quality. The honey bees can be used in large
numbers, especially the domestic ones as these can be transported to the concerned
field. Since honey bees are placed in the respective fields in various developed countries
to enhance yield of crops, it is desirable that the same methodology can be applied here
on a large scale. There are many examples of successful management of bee pollination
on various crops in other countries but worth mentioning is that of california almonds in
USA where bee pollination saved the crop from its decline. Using hives in the field to
pollinate is not at all common in India. We can also bring together farmers and bee
keepers for using bee hives in various fields for increasing the yield and quality. In this
way both the farmers and bee keepers are mutually benefited; the farmers in getting
good market price for quality crop and the latter in getting money for leasing out hives.
The use of other insect pollinators (other than domestic bees) like bumble bees, solitary
bees ( Andrena sp., Xylocopa sp., etc.), especially where crops are inadequately
pollinated by honey bees should also be encouraged. This practice is already in use in
other countries. The use of pesticides if avoided, when the crop is in bloom, can have
positive effect in maintaining the population of pollinators. The wild vegetation needs to
be conserved because these serve as alternate food supply for pollinators in the absence of regular hosts. It will be good to stop logging off the woods; removal of hollow
trees (that provide nest for bees ) and also pushing out of the hedgerows which are home
for solitary native bees and other pollinating agents. Alternative agricultural techniques
can provide non-toxic methods of weed and insect control. The production of organic
foods need to be encouraged as it fetches premium prices; at least this technique can
be used in small kitchen gardens to maintain the balance in the environment.
37
Suggested Readings
Abrol, D. P. 2009. Bees and Beekeeping in India (2nd ed.). Kalyani Publ., Ludhiana,
450 pp.
Abrol, D. P. (downloaded 2012). Applied pollination : Present scenario. Pollination
Biology . Springer, Netherland, pp. 55-83.
Batra, S. W. T. 1985. Bees and pollination in our changing environment. Apidology,
26 : 361-370.
Benedek, P. 1996. Insect pollination of fruit crops. In : Nyek: J. Soltesz, M. (eds.).
Floral Biology of Temperate Zone Fruit Trees and Small Fruits . Akademiai Kiado,
Budapest, Hungary, pp. 287-340.
Buchmann, S. L. and G. P. Nabham. 1996. The Forgotten Pollinators . Island Press,
Washington, D.C.
Corbet, S. A. 1993. Wild bees for pollination in the agricultural landscape. In : Bruneau
(ed.). Bees for pollination. Commission for European Commn., Brussels, Belgium,
pp. 175-189.
Crane, E. 1992. The past and present status of beekeeping with stingless bees. Bee
World 77 : 29-42.
Delaphane, K. S. and Myer, D. F. 2000. Crop Pollination by Bees . Cabi publ.,
Cambridge.
Deodikar, G. B. and Suryanarayane, M. C. 1972. Crop yields and bee pollination. Indian
Bee J . 34 : 53-64.
Deodikar, G. B. and Suryanarayane, M. C. 1977. Pollination in the services of increasing farm production in India . In : P. K. K. Nair (ed.) Advances in Pollen Spore Research, pp. 60-82, Today & Tomorrow Publ., New Delhi (2nd ed.).
Free, J. B. 1993. Insect Pollination of Crops (2nd ed.). Acadmic Press, New York,
pp. 684.
38
BIO-ECOLOGY AND UTILIZATION OF BUMBLE BEE
IN CROP POLLINATION
Raj Kumar Thakur and Jatin Soni
Department of Entomology and Apiculture,
Dr Y S Parmar University of Horticulture & Forestry, Nauni, Solan 173 230 (HP)
The most reliable and efficient form of cross-pollination is through insects. Many
insects such as honey bees, bumble bees, and solitary bees are in commercial use for
pollination. The most out crossing fruit crops depend upon pollinators, mainly insects.
There is need for conservation and augmentation of pollinators like bumble bee (Bombus
sp.) for pollination. But recently there is reduction in domesticated honey bee colonies
all over the world due to mites and various pests menace. To fill up this gap it is utmost
important that we should have some alternative back up pollinators such as bumble
bees which can fulfil the need of farmers and orchardists for recovering the ever declining productivity. Fortunately bumble bees are advantageous over the honey bees due to
their long working hours, long tongue length, effectiveness in less numbers and their
capacity to forage vigorously at low temperature and low light intensities.
Honey bees tend not to forage on nectar-less flowers and are less efficient to pollinate flowers with deep corolla because of their small size and smaller tongue length
incapable of stigmatic contact. Honey bees also remain confined to their hives during
cool and inclement weather. However, under conditions at which honey bee activity is
limited, bumble bee can forage at low temperature and inclement weather and are
especially valuable in "buzz pollinating" flowers (Buchmann 1983, Corbet et al. , 1991).
Bumble bees are major pollinators of many crops and wildflowers in the temperate northern hemisphere. There is considerable evidence that many bumble bee species have
declined dramatically in recent decades, both in the UK, in continental Europe and in
North America (Williams 1991, 1994). Bumble bee, common name for any of a group of
large, hairy, usually black and yellow, and social bees. They are found primarily in
temperate regions at higher altitude than other bees. However, colonies of bumble bees,
unlike those of honey bees, only survive during the warm season; new colonies
hibernate alone to begin another colony the following spring. In addition, there are
usually fewer individuals in a bumble bee colony than in a honey bee colony, and bumble
bees do not use a dance to communicate the location of food to other members of the
colony, as honey bee do. Bumble bees are important pollinators of many plants. Both
queen and worker collect pollen and transport it back to the colony in pollen basket of
hind legs. Workers are small if born early in the season and large if borne later in
the year. Differences in body size, and especially in tongue length, are important in
determining which flower species it will visit for nectar and may determine which plant it
will pollinate.
Bumble bees are important pollinators of crops and native plants. There are dozens
of species of bumble bees in the world. Most of them are excellent pollinators of a wide
variety of crop, although in some plant species they cut a hole in the base of the corolla
39
and "rob" the nectar without effecting pollination. There is much interest in conserving
and augmenting wild populations of bumble bees for pollination. With the increase in the
acreage under protective cultivation in India, the role of bumble bee pollination became
more important as honey bees are not suited to this environment. Rearing of bumble
bees and their utilization in pollinating crops grow in poly houses has taken the shape of
industry in western world. In India very little attention is paid in respect of their biology,
nest architecture, nesting habitat, domestication of bumble bee colonies artifically and
utilization of laboratory reared bumble bees in pollination of crops except few attempts.
BUMBLE BEE DOMESTCATION
This conservation can be achieved through constructing the artificial structures, providing alternate host plant and the modification of adverse agricultural practices. Bumble
bees are well known important pollinators in their natural habitats. Their use to pollinate
various crops has been developed widely and their mass rearing techniques have been
developed extensively in many countries. Bumble bees offer a environmental service
critical to natural vegetation and agro ecosystems especially in highlands where other
alternative pollinators are rare or absent. (Kevan et al. , 1991).Many attempts have been
made earlier by different workers to rear various species of bumble bees by artificial
methods in cages of different dimensions, materials and descriptions (Sladen, 1912,
Plath 1923, Frison 1927, Ptacek 1985, Ono et al. , 1994). Hasselrot (1952) reared hibernated bumble bee queens of B. terrestris , B. hyponorum and B. lapidaries in a closed
glass covered boxes containing a honey syrup feeder, with a small entrance hole. The
queen initiated colony raising by the end of April. Ptacek (1985) reared bumble bees in
wooden boxes of inner dimensions 100 x 70 x 70 mm being divided into two unequal
parts and fed with 60% and pollen dough made of corbicular pollen. Artificial domiciles
were used by Friden (1966) for observing nest building and colony initiation of B.
lapidaries and B. lucorum queens being captured during spring. Macfarlane et al. , (1990)
developed rearing of B. terrestris , spring collected queens in two screen measuring (4 x
4 x 2 m) and fed with 50% sugar solution, grounded corbicular pollen pellets and were
maintained at 18-25 oC temperature. Thakur and Kashyap, 2007 carried out domestication of bumble bee successfully under controlled conditions maintaining the temperature
of 25-30 oC and 60-65% relative humidity and by feeding them sucrose solution (50%)
and corbicular pollen.
NEST SITE AND NEST ARCHITECTURE
Bumble bee usually made their nest in the ground in a deserted mouse nest or bird
nest.The most suitable areas for bumble bee nest are an underground chamber, where
the queen checks out old burrow of mice, moles or chipmunk etc. For building the nest,
queen begins collecting moss, grasses and leaves forming a soft ball of these materials
inside the burrow. Sadly, these affable insects are struggling to survive in a modern
world due to their habitat loss, indiscriminate use of pesticides, invasive pollinating
species and intensive agriculture. Queens of B. lapidarius and B. terrestris seem to
favour the underground tunnels as nesting site while the queens of B. agrorum , B.
ruderarius and B. muscorum usually select the nesting place on the surface of ground
40
(Sladen, 1912; Postner, 1951; Free and Butler, 1959). Thakur (2002) made the first
attempt to study the nest architecture and domicilation of bumble bee, B. haemorrhoidalis
in India. Nests were found near the abandoned rodents. Nest architecture and the
construction behaviour of bumble bees Bombus transversalis was seems to be
constructed on the surface of the ground and small wooden twigs, leaves and grass was
incorporated in the nests as a support for firm structure. The brood was under the canopy
or covering of tightly woven leaves, rootlets and grass which was cut and accumulated
by the workers and placed in shady dark place (Taylor and Cameron, 2003). Bumble
bees play a significant role in pollination of both wild plants and crops. In the past
decade, there has been increased interest in managed colonies of bumble bees, Bombus
spp. for crop pollination. This development followed a breakthrough in the ability to mass
produce bumble bee colonies. Bumble bees are basically a temperate group and have
more than 240 species (Williams, 1998). These are mostly found at high altitudes in
abundance in cool temperature conditions in the northern hemisphere and some species
also found in sub tropical regions (Plowright and Laverty, 1984). To rear bumble bee
under laboratory different types of domiciles are used for mass production of bumble bee
under controlled conditions.
DOMICILES OF BUMBLE BEES
Different domiciles have been used by different researches for the successful rearing
of bumble bees in laboratory. Queens were placed in wooden containers consisting of
two boxes having 7.5 x 7.5 x 5 cm as internal diameter with glass roof and corrugated
paper floors (Sladen, 1912 and Plath, 1923). Closed glass covered boxes containing a
honey syrup feeder were used, with a small entrance hole. These boxes were filled with
moss litter, a hollow ball of cellulose material for placing pollen dough (Hasselrot, 1952).
Metal domiciles in wooden boxes, plain wooden boxes or pottery domiciles with
sufficient insulation material were tested and were found useful for the rearing of bumble
bees (Fye and Medler, 1954). Boxes with insulating earth material having peat litter and
sphagnum were tested and found better domiciles (Holm et al. , 1960).
Wax paper boxes (9.5 x 9.5 x 5 cm) with glass roofs (Containers) were used for the
domicilation of Bombus hyponorum and it was reared up to 5 generation without going
into diapause but these domiciles were not found suitable for the rearing of Bombus
rufocnictus, Bombus terricola, Bombus perplexus and Bombus tennarius . Aluminium
tubes filled with damp vermiculite, damp decaying wood, or damp paper for putting queens
into hibernation were successfully tested (Horber, 1961). Artificial domiciles were used
by Friden (1966) for observing the nest building and colony development in bumble bees
by putting glass on the top of domiciles. Plowright and Jay (1966) tried to rear the
bumble bees under laboratory conditions by putting the hibernated queens in plastic
cages (5 x 5 x 3 cm) and they found that colony initiation could be observed in these
boxes.
Cumber (1963) developed successful nest boxes for bumble bees. Domiciles have
two compartments having a colony compartment for bumble bee brood and a vestibule to
provide pollen and sugar water. He suggested that glass can be used to enable the
41
observer to observe the colony without disturbance. Knee and Medler (1965) suggested
wooden boxes with an entrance hole in one side near the bottom. Boxes were 9 inches
long and about 6 inches deep with a detachable lid or roof. The lid had over hanged sides
with rain proof material to keep the interior dry and some holes on the top for ventilation.
Two chambered boxes were tested having one big chamber for colony development
and small one, vestibule for feeding and defecation. Box were made out of plywood,
concrete polystyrene and plastic but there was problem for the escape of water vapours
and moisture which made colonies susceptible to mould (Macfarlane et al., 1983). First
time screen cage measuring 4 x 4 x 2 cm high were used for the rearing of Bombus
terrestris in Newzealand to pollinate Kiwi and Lucerne crops (Macfarlane et al. , 1990).
Two chambered boxes having brood (15 x 17.5 x12 cm) and feeding chambers (9 x 17.5
x 12 cm) were enclosed in a big box (25 x 17.5 x 12 cm) and were connected with a
passage hole were used for the rearing of Bombus hypocrita and Bombus ignitus (Ono
et al., 1994 and Gretenkord and Drescher, 1997). Boxes of thin propylene sheets stapled
to the corners with a hinge lid were developed. The roof was slanted and larger than the
box to protect the bees from rain (Munn, 1998).
Delplane (1995) tested different boxes and recommended specific cages at different
stages i.e. initiation and development of bumble bee colony. He tried starter boxes (9 x
3 x 5 inches) for the initiation of colonies having two chambers, one for brooding and the
other for feeding and defecating. After the starting of colony, the queens with brood
transferred to finisher boxes (8.2 x 2 x 4.5 inches). Two 0.75 inches holes were drilled
in between two chambers to facilitate movement of bees between the chambers.
Eijnde et al. (1991) developed rearing cages of 12cm x 5.5cm x 11 cm having glass
windows in the front and rear side and a small feeder in the top. Some holes were
provided for ventilation on the sides. Wooden boxes having internal dimensions of 25 x
25 x 30 cm and 25mm hole in the centre above wooden floor with waterproof base, sides
and roof were used for the domiciliation of Bombus hortorum (Donovon, 2001). Coffee
can cottages were developed used for the bumble bee domicilation. The large coffee can
were taken and was linked with corrugated cardboard cut to fit inside the can. The
circular pieces of cardboard were cut to fit at the top and bottom of can and a ¾ inches
hole was cut through the top piece for the door. Several small holes were also made to
facilitate the ventilation and the can was filled 1/3 to 2/3 with fibrous material (Pehling,
2002). Two chamber wooden boxes were used for the rearing of Bombus haemorrhoidalis
under laboratory conditions. (Thakur, 2002 and Thakur et al. , 2005).
Ventilations slits were used in the plastic screen cages on the bottom, side walls
and lid so that the excessive moisture lost outside. The entrance of the cages can be
closed and opened as per the need of the colony (www.biobee.com). Kashyap (2008)
studied different domiciles for rearing of bumble bee ( Bombus haemorrhoidalis Smith).
Two chambered wooden boxes, cardboard boxes and hoarding cages were used and
were found that wooden two chambered box and hoarding cages were accepted by the
queens and they raised their progeny successfully in these cages.
42
LIFE CYCLE OF BUMBLE BEE
Bumble bee colonies follow an annual cycle. The large queens are the only bees
remaining from summer brood. The newly emerged queen commences foraging for
collection of nectar for energy and pollen for completion of her own reproductive development. Bumble bees are generalist feeders in contrast to some solitary bees that collect
pollen from only from one or few related species of plants. The bumble bee queen must
perform all the tasks of worker bee because she is the sole founder of the colony. Unlike
honey bee queens who have reduced mouth parts and eyes, short antennae and no
pollen collecting hairs, bumble bee queens are completely functional. When the queen
first leaves her new nest she flies about the nest site entrance in ever widening circles
before leaving the location. This orientation flight presumably helps her to remember
landmarks so that she can relocate the nest. The queen foragers at flowers for nectar
and pollen. In the centre of nest she produces a wax cell in which she will lay her eggs.
Initially the nectar pot serves as reserve supply for the queen, who may consume it
during the night or during periods of bad weather when she cannot forage. Additional
pots will serve the entire colony. A fertilized eggs develops into a diploid individual
usually female bearing two sets of chromosomes per cell, one set each from the mother
and the father and unfertilized egg develops into a haploid male with a single set of
chromosomes per cell, his genetic makeup is derived solely from the queen. The ideal
nest temperature is between 30-32 oC. The eggs hatch in three to four days. The bumble
bee larva has a head, three thoracic, and ten abdominal segments. It lacks legs, eyes
and hair it has only fleshy lobes surrounding its mouth. Initially pale, it changes to
pinkish gray or brown and passes through four larval stages or instar before pupation.
The first brood tends to be small in terms of both the number and the size of individual
because only the queen is feeding the larvae. A colony that is starved later in development may also produce tiny workers. Captive colonies that are overfed may produce
giant, queen sized workers.
The queen uses one of two methods to feed the larvae. These methods are consistent within species so some species are referred to as "pollen storers" and others as
"pocket makers". The pollen storers keep a reserve supply of pollen available in the nest
to feed the larvae. At later stages of colony development this pollen is stored in old
cocoons that have been modified by adding wax to increase their height. The queen feed
the larvae by biting a hole in the larval cell and regurgitating a mixture of pollen and
honey into cell. As the larvae grow they form separate chambers and are fed individually.
Pollen makers build wax pockets adjacent to the larval cell and supply them with pollen
from which larvae feed directly. Pocket makers occasionally feed the larvae by regurgitation. Most larvae share a common pollen store and must compete for their share. This
can result in size differences among the workers. The larvae pass quickly through the
four instars, so in seven to fourteen days they are ready to pupate. Silk is released from
the salivary glands as the larva spins around in its cell making a cocoon. Pupation lasts
about fourteen days. The first workers emerge from their cocoons about five weeks after
the eggs were laid.
43
MORPHOMETRIC STUDIES
A morphological character that is body size, tongue length, wing length has direct
and indirect effect on the efficiency of insect pollinators. In Bombus spp. tongue length
was measured to be 11.1 mm (Stapel, 1933), 12.3 mm in B. hortorum (Medler, 1962),
5.0 mm in B. frigidus (Hobbs, 1968), 12.08 mm in B. haemorrhoidalis, where as 11.4 mm
in B. ardens, 10.7 mm in B. hypocrite and 17.5 mm in B. diversus (Inoue and Yokoyama,
2006).
BUMBLE BEE AS POLLINATOR
Pollination highlights the need for pollination management of certain crops with unstable yield and can help growers to select appropriate pollinating species and management options and to utilize their resources effectively. Significance of insect pollinators
in increasing the crop productivity in self - fertile and self-incompatible varieties of fruit
crops grown under different agro climatic conditions is an established fact. Worldwide
an estimated 35% of crop pollination is dependent on insects which are
bringing pollination for 70 to 108 major crops (Mc Gregor, 1976 and Klein et al ., 2007).
Pollinators are absolutely necessary for fruit set and seed formation of some crops(Crane
and Walker, 1984; Rasmussen, 1985). To obtain pollen the insect pollination must grip
and vibrate the wing muscles. In this way the pollen grains are dislodged and fall on to
the insects an activity termed as 'buzz pollination' (Buchmann, 1983). Bumble bees are
capable of doing this and this makes them valuable pollinators of buzz pollinating crops
such as blueberry, eggplant, seed potato, hot/sweet pepper and tomatoes. (Plowright
and Laverty, 1984; Cane and Payne, 1990,1993) Bumble bees are adapted to a diversity
of climates and habitats, and are active even when light intensity is low and able to
continue foraging even at temperatures as low as 10 oC and as high as 32 oC. Their
increased mobility allows them to continue flower visits for most of the year, unlike
honey bees, which are mostly inactive at temperatures below 16oC (Heinrich 1979). Bumble
bees can forage during adverse climatic conditions, even flying during light rain, visiting
from 20-50 flowers per minute with high pollination efficiency. Consequently, many early
spring and late fall flowering plants benefit from pollination services provided by members of this hardy genus. Bumble bees are important pollinators of crops and native
plants. There are dozens of species of bumble bees in the world. Most of them are
excellent pollinators of a wide variety of crops, although in some plant species they cut
a hole in the base of the corolla and rob the nectar without effecting the pollination.
There is a much interest in conserving and augmenting wild populations of bumble bee
for pollination. Bumble bees are known important pollinators in their natural habitats.
Their use to pollinate various crops has been developed widely and their mass rearing techniques have been developed extensively in many countries (Pinchinat et al. ).
Bumble bees offer an environmental service critical to natural vegetation and agro ecosystems especially in highlands where other alternative pollinators are rare or absent.
(Kevan et al. , 1991, Morandian et al. , 2001). Bumble bee flowers tend to be brightly
coloured and visibly distinct from the background of green vegetation. Bees have good
colour vision, shifted towards the blue end of the spectrum compared to our own vision.
44
Natural pollination using bumble bees ( Bombus impatiens ) is an effective way of
increasing profits and reducing labour costs. Bumble bees can increase crop production
through more efficient pollination. As bumble bees are efficient and more reliable
pollinators particularly under adverse conditions particularly like low temperature and
inclement weather.
Under Nauni conditions Bombus haemorrhoidalis was recorded to forage on different
wild, medicinal and cultivated flora. They were found mostly to visit medicinal, vegetable
and ornamental plants. Activity of bumble bee was found maximum during morning and
evening hours. Resource partitioning studies of bumble bees with honey bees and other
pollinators revealed significant differences in the relative abundance of bumble bees,
honeybees and other pollinators on medicinal plants ( Clitoria terminalis, Solanum
sissymbrifolium, Solanum lacinatum, Digitalis purpurae, Oenothera biennis, Plantago
lanceolata, Hypericum perforatum, Alpinia calcarata, Chichorium intybus and Solanum
indicum ) and ornamental plants ( Duranta spp. and Gladiolus spp.) while on vegetable
crops like Solanum melongena and Cucumis sativus the relative abundance of bumble
bees was found similar with honey bees and other pollinators.
Bumble bee colonies were reared both in laboratory (incubator) and room temperature conditions. Bumble bee queens kept at 26.9oC and 65-70% relative humidity fed
with 50% sucrose solution and honey bee collected pollen pellets in laboratory while
under room temperature conditions (32-36oC and 50-60% relative humidity) queens were
fed with 50% sugar solution and grinded pollen pellets. It was found that bumble
bees can be reared under room temperature conditions if the temperature and humidity
fluctuate between 32-36 oc and 50-60% relative humidity. It was also found that with the
use of bumble bees as a pollinator of cucumber in poly house, an increase of 22% in the
total returns was observed as compared to control. The cost benefit ratio in cucumbers
grown under poly house conditions was found to be 1 : 2.02.
As bumble bee rearing refined wooden domiciles are able to remove the problems
related to increasing moisture, cleaning debris, observing colony activity and ventilation
so can be utilized to enhance the success of bumble bee rearing technology to meet the
increasing need of pollinators in open cultivation and protected cultivation of crops.
Pollination through bumble bees in cucumber resulted in higher fruit set, healthy fruits,
fruit weight, fruit size, seed number and seed weight, therefore, it is concluded from the
present studies that the pollination by bumble bee ( Bombus haemorrhoidalis) in
protected conditions is best mode of pollination for pollinating cucumber crop and should
be exploited to enhance the yield and quality of cucumber fruits grown under protected
conditions.
More over they are better pollinators for the crops requiring buzz pollination (Corbet
et al ., 1982, 1988, Erikson and Buchmann, 1983). Many crops are well suited to natural
pollination with bumble bees, including cucumbers, peppers, tomatoes, vegetables, seed
crops, strawberries, blueberries, cane berries, melons, and squash.
Due to high pollinating performance and adaptability to various environmental
45
conditions, bumble bees remain the focus of interest to study pollination biology or
apply the result in agricultural and horticultural practices. In India Non- Apis sp. have
received a very little attention particularly in respect of their management for pollination
of target crops. Orchards surrounded by cultivated land had about eight fold less bumble
bee activity than the orchards in the areas otherwise uncultivated. Clean and intensive
cultivation has destroyed locations and nesting sites of wild pollinators as well as their
many natural food resources. The wild bees are well known and valued as important
pollinators of crops and other plants. In fact in several countries some species are commercially raised and used for pollination of crops not effectively pollinated by honey
bees. Wild pollinators especially bumble bees are more valuable for pollination of many
crops. Bumble bee visits twice as many flowers per unit time as compared to other
pollinators and work dawn to dusk. In Himachal Pradesh due to inclement weather conditions prevailing at peak flowering there is generally a low fruit set owing to inability of
bees to work at low temperature. In such situations bumble bees can play a pivotal role.
The state constitutes one of the most important areas because of four distinct agroclimatic conditions ranging from foot-hills, sub-temperate, temperate and temperate
desert. Such varied habitats and climatic conditions have encouraged the cultivation of a
number of fruits, vegetables and other commercial crops which differ greatly in their
pollination requirements.
MATING BEHAVIOUR
The mating behaviour of bumble bee under natural conditions generally observed
during late morning and early noon hours. Drones came out of the nest came out of the
nest and started walking around the nest. Some drones start flying around the queens.
The drones pushed the queen to the ground and they start mounting over the queen. The
mating last for different time intervals. The mated queen remated with other competing
drones. All the mated queens entered back into their nests after mating while the drones
flew away.
In temperate zones, bumble bees have one generation per year, only few observations were recorded for second generation could exist in the field. (Meidell,1968).
The entering of diapause is an endogenous queen caste characteristic independent of
temperature and light. Investigations have shown that the specific physiology of young
queens is based upon a low juvenile hormone in haemolymph (Roseler, 1976; 1977).
When newly emerged queens are treated with juvenile hormone, glycogen and lipids are
not accumulated in the fat body, but oogenesis is induced and the queens start
egg laying after some days. The most effective approach to the bumble bee rearing is
catching the fecundated queen and rearing it in the laboratory conditions. The need of
laboratory domiciles arise because they can be cared well in the laboratory and when
colonies become large enough, they can be shifted to the field for pollination (Hasselort,
1952).
The economic aspect of using bumble bees as pollinator is their, year round
availability. Bumble bee colonies undergo one generation per year. Queens are the only
caste to overwinter and worker and male die during late summer and early autumn.
46
15 x 20 x 8 cm (D 1)
16 x 12 x 10 cm (D 2)
25 x 20 x 15 cm (D 3)
33 x 20 x 10 cm (D 4)
Removable top cover
Removable inner cover, base and glass
Perforated base
Ventilation holes
Different types of domiciles and refinements incorporated
used for the rearing of bumble bee in captivity
Eggs of bimble bees
Queen moulding wax into cells
Emergence of workers
Growing colony
Initiation and growth of bumble bee colony in artificial domicilies
Queen coming out of the nest for mating
Drones congregated egated at the nest
Mating in bumble bee queen and drones
Drone mounting ovar a bumble bee queen
Cessation of bumble bee mating
Queens returened back to the nest
Observations of the mating behaviour of bumble bee
under natural conditions
Bumble bee flora in Himachal Pradesh
Common name
Botanical name
Citrus
Citrus sp.
Pear
Pyrus communis
Caryopteris
Caryopteris bicolour
Kachnar
Rosemary
Family
Flowering time
Source
Rutaceae
February-March
N
Rosaceae
February-March
N+P
Verbenaceae
February-April
N+P
Bauhinia variegate
Caesalpiniaceae
February-April
N+P
Rosmarius officinalis
Lamiaceae
February-April
N+P
Salvia
Salvia moorcroftiana
Lamiaceae
February-April
N+P
Radish
Raphanus sativus
Rutaceae
March-April
N
Scutellaria
Scutellaria linearis
Labiatae
March-April
N
Wisteria
Wisteria sinensis
Leguminosae
March-April
N+P
Antirrhinum
Antirrhinum majus
Scrophulariaceae
March-May
N+P
Lavender
Lavendula sp.
Lamiaceae
March-May
N
Gladiolus
Gladiolus grandiflorus
Iridaceae
April-May
N+P
Honey sucker
Lonicera japonica
Caprifoliaceae
April-May
N
Robinia
Robinia pseudoacacia
Iridaceae
April-May
P
Wild Ber
Zizyphus mauritiana
Rhamnaceae
April-May
N
Yellow Gulmohar
Peltophorum ferrugineum
Caesalpiniaceae
April-May
N
Basuti
Adhatoda vasica
Lamiaceae
April-June
N+P
Chameli
Jasminum primulum
Scrophulariaceae
April-June
N
Oee
Albizia chinensis
Mimosaceae
April-June
N
Sky flower
Thunbergia grandiflora
Acanthaceae
April-June
N+P
Olive
Olea europea
Oleaceae
May-June
N
Pomegranate
Punica granatum
Punicaceae
May-June
N+P
Shain
Plectranthus rugosus
Labiatae
May-June
N+P
Banah/Vitex
Vitex negundo
Vitaceae
May-July
N+P
Bitter Gourd
Momordica charantia
Cucurbitaceae
May-July
N+P
Pumpkin
Cucurbita moschata
Cucurbitaceae
May-July
N+P
Shoe flower
Hibiscus rosa sinensis
Malvaceae
May-July
N
Brinjal
Solanum melongena
Solanaceae
June-August
N+P
Sweet Pepper
Capsicum annuum
Solanaceae
June-August
N+P
Delphinium
Delphinium sp.
Ranunculaceae
August-September
N
Chinese Raintree
Koelreuteria paniculata
Sapindaceae
August-September
P
Loquat
Eriobotrya japonica
Rosaceae
October-November
N+P
Sedum
Aptenia cordifolia
Aizoaceae
Spring summer
N
Golden Duranta
Duranta plumier
Verbenaceae
Throughout year
N
Marigold
Tagetes sp.
Asteraceae
Throughout year
P
47
Methods have been developed to raise colonies of bumble bees for whole of the year
according to the requirement. Towards the end of the colony cycle in late summer, young
queens and males are produced. After mating the young queen go into diapause while,
the workers, and the males of a colony die. In the following spring the queen that survived give rise to the next Bumble bees do, however show great ecological flexibility,
particularly in terms of diapause response (Estoup et al., 1996, Dafni, 1998).The long
hibernation period, the single colony cycle per year, the variability in the social structure
of the colonies such as timing of reproduction and sex ratio, and the lack of shelf life are
major obstacles in the year round rearing of bumble bees (Hughes,1996). Several
authors have observed aestivation (Jonghe, 1986; Gurel et al ., 2008) and bivoltinism
(Douglas, 197357; Buttermore, 1997) in some bumble bee populations. Diapause is an
adaptive strategy for survival in unfavourable environmental conditions. Adverse periods
can thus be avoided and by exploiting suitable environmental conditions, development
can be actively resumed when favourable conditions return (Denlinger, 2008).. It was
discovered that a CO 2 treatment induces ovary development of young mated queens and
there by prevents queens for entering diapause. In recent years the storage of hibernating queens at low temperature for several months to mimic diapause has been widely
used in commercial breeding (Roseler, 1985).
Suggested Readings
Buchmann, S.L. 1979. Bumble Bee Economics . Harward University Press. Cambridge.
p. 245.
Buchmann S. L.1983. Buzz pollination in angiosperms. In : Jones C. E. and Little R. J.
(eds.), Handbook of Experimental Pollination Biology. Van Nostrand Reinhlod
New York. pp. 73-113.
Buttermore R. E. 1997. Obsrvation of successful Bombus terrestris (L.) (Hymenoptera :
Apidae) colonies in Southeren Tamania. Australian Journal of Entomology.
36 : 251-254
Cane J. H. and Payne J. A. 1990. Native bee pollinates rabbit eye blueberry. Alabama
Agric. Exp. Stn . 37 : 4
Cane J. H. and Payne J. A. 1993. Regional, annual and seasonal variation in pollinator
guilds : Intrinsic traits of bees (Hymenoptera : Apidae) underlie their patterns of
abundance at Vaccinium ashei (Ericaceae). Ann. Entomol. Soc. Am. 86 : 577588
Chauhan Avinash and Thakur Raj K. 2010. Nest architecture studies of bumble bee,
Bombus haemorrhoidalis Smith. Pest Management and Economic Zoology.
18 (1/2) : 157-61.
Chauhan, Avinash, Thakur Raj K. and Soni Jatin. 2010. Bumble bees as dominating
insect visitors of some important medicinal plants Pest Management and
Economic Zoology. Pest Management and Economic Zoology. 18 (1/2) : 342347.
48
Corbet S. A., Beament J. W. L. and Erisikowitch D. 1982. Are electrostatic forces
involved in pollen transfer. Plant Cell and Environment 5 : 125-129
Corbet S. A., Chapman H. and Saville N. 1988. Vibratory pollen collection and flower
form : bumblebee of Actinidia, Borago and Polygonatum. Functional Ecology .
2 : 147-155.
Corbet S. A., Williams I. H. and Osborne J. L. 1991. Bees and the pollination of crops
and wild flowers in the European community. Bee World 72 (2) : 47-59.
Crane E. and Walker P. 1984. Pollination directory for world crops. Int. Bee Res.Assoc .,
London. 183 pp.
Cumber R. A. 1963. Some aspects of biology and rearing of bumble bee bearing on the
yields of red clover in New-zealand. Newzealand Journal of Science . 6 : 66-74.
Dafni A. 1998. The threat of Bombus terrestris spread. Bee World 79 : 113-114.
Daily G. C. 1997. Nature's services : Societal dependence on natural ecosystems .
Island Press, Wasington, DC p. 412.
Delplane Keith S. 1995. Bumble beekeeping: queen starter box. American Bee Journal
pp. 743-745.
Denlinger D. L. 2008. Why study diapause? Entomological Research 38 : 1-9
Donovon B. J. 2001. Calculated value of nests of long tongued bumble bee Bombus
hortorum , for pollination of tetraploid red clover Trifolium prantese . Acta
Horticulturae 521 : 293-296.
Douglas J. M. 1973. Double generations of Bombus Jonellus subborealis Rich.
(Hymenoptera : Apidae) in an arctic summer. Entomologica Scandinavica
4 : 283-284
Eijnde J. Vanden, Ruitjjer A. and Steen J. Vandeer. 1991. Method for rearing Bombus
trestris continuously and the production of bumble bee colonies for pollination
purposes. Acta Horticulturae 288 : 154-158.
Erikson E. H. and Buchmann S. L.1983. Electrostatics and pollination In : Jones, E.E.
and Litle R.J. (eds.). Hand Book of Experimental Pollination Biology. New York;
Van Nostrand Reintold pp. 173-184
Estoup A., Solignac M., Cornuet J. M., Goudet J., Scholl A. 1996. Genetic differentiation of continental and island populations of Bombus terrestris (Hymenoptera :
Apidae). Molecular Ecology 5 : 19-31
49
BIOECOLOGY AND MANAGEMENT OF LEAFCUTTER BEES
Yogesh Kumar
Department of Entomology,
CCS Haryana Agricultural University, Hisar - 125 004
The sustainable development of agriculture has necessitated the reorientation of the
present crop production technologies. Instead of making substantial use of chemical
fertilizers, biocides, irrigation facilities and heavy machinery for yield enhancement,
a shift towards biologically based agriculture will become necessary to increase food
productivity. Concerted emphasis in future should be on the full utilization of underutilized
resources which are environmentally more friendly. One such resource is an increase in
the yield of different cultivated crops through cross pollination by insect-pollinators.
Among the insect pollinators, bees are important and can be managed easily and
utilized for the purpose of increasing yields of different crops. Friese (1923) estimated
that out of 20,000 species of bees (superfamily; Apoidea), only 4-species of honey bees
and 300 species of stingless bees (Family; Meliponinae) live in the permanent perennial
colonies. The majority of bees are solitary where a female constructs a nest consisting
of one or more brood cells provisioned with nectar and pollen that provide food for the
larvae that will emerge from the eggs she deposits just before the sealing of the cell. In
general, two-third of bee fauna is comprised of solitary bees (Michener, 1965; Batra,
1977; Bingham, 1987).
According to Michener (2000), more than 16,325 species of bees belonging to 425
genra, reorganized under 7 families have been recognized. In North India, Batra (1977)
recorded 89 species of solitary bees out of 97 species studied. The major bee genera in
India belong to family Megachilidae and Athophoridae and are commonly distributed in
India. Much has been explored on various aspects of honey bees ( Apis spp.) such as
their distribution, domestication, management for honey production and crop pollination, however this is not true for non- Apis bees which also play an important role in the
pollination of various crops and wild flowering plants.
Inspite of being represented in large numbers, non- Apis bee pollinators have
received little attention. The probable reason seems their unpredictable seasonal
availability, lack of knowledge about their biology and host plant relationship. It was only
in mid-sixties that scientific interests were generated to study and understand their life
processes in India (Atwal, 1970). Failure of honey bees in pollination of crops which
require tripping, dwindling of bee colonies due to acute floral dearth and adverse climatic
conditions and prevalent bee diseases has created a necessity for exploration of alternative yet suitable non-apis bee pollinators to augment crop yields. In addition to alfalfa,
clovers and fruits like apple, pear, peach, almond and several other crops such as sunflower, hybrid tomato, cotton, onion, carrot (Mc Gregor, 1976) and cucurbits (Kapil and
Dhaliwal, 1968; Abrol, 1985) can be the future potential crops requiring the services of
the non- Apis bee pollinators.
50
A solitary bee species is one in which the female prepares and provisions the cell,
deposit the egg and then seals the cell completely unassisted. More than one cell can
be constructed, but only one at a time. After the cell is sealed, no further attention is
given to it and the adult may die within few days. Gregarious bees are solitary individuals that endeavor to nest in close proximity to each other. The Megachile (leaf cutter
bee) belongs to this category. Social bees live together in a society and have divided
duties. The queen is the sole or primary egg laying individual. Her active life is relatively
prolonged and she maintains contact with at least some of her adult offspring. The
distance that the different species of wild bees may forage vary enormously. Janzen
(1971) reported that an individual Euplusia surinamensis returned to its nest from a
distance of 23 km. Stephen (1959) reported that the alkali bee ( Nomia melanderi) may
forage 4 or 5 miles from its nesting site. The alfalfa leafcutter bee ( Megachile pacifica )
usually forages within only a few hundred feet of the nest (Bohart 1962b). Visitation to
plants by wild bees is highly variable. Some species visit many different families of
plants. Others visit only a few closely related families and still others visit only a single
species or closely related species. In different instances, each type of activity would be
advantageous.
Members of Megachilidae family use their large, scissor like mandibles to gather
pieces of leaf, flower petals, mud or plant resins for the construction of their nests. The
genus, Megachile includes bees that construct nests out of leaf pieces or flower petals
called the leaf cutter bees. Parallel rows of pollen collecting hairs located on the underside of the female bee's abdomen, called the scopa are silver or gray in colour. Some
other female leaf cutter bee species usually have black, tan or yellow scope. Female
alfalfa bees are larger than male bees with a few gray hairs around the face and a sting
at the tip of their pointed abdomen. Despite having a sting, female leaf cutters are not
aggressive, and rarely sting even when handled. The sting is also much less painful than
that of a honey bee. As a result beekeepers do not need any special protective equipment when working with leafcutter bees. Male bees have conspicuous green eyes, yellow hairs around the face, slightly longer antennae and straight, non-tapered abdomens
with no scopa and stinger.
All the leafcutter bees are solitary, meaning that each female bee independently
constructs her own nest, provisions the nest with pollen and lays eggs. There is no
queen and the bees do not live together as a social unit like honey bees do. Female leaf
cutters do not interact with other bees or with their own offspring after laying their eggs.
Alfalfa leafcutter bees are gregarious however, meaning that they have a tendency to
construct their nests near each other, hence large numbers of bees can be housed in a
single structure containing multiple nests. Other leafcutter bee species will nest in
manmade nests, however, most species are difficult to manage because they are not
gregarious. Male leaf cutter bees have no role in the construction or the provisioning of
nests. Upon their emergence as adults, male leafcutters mate one or more times and
may live for several weeks, then die. While they may feed on small amounts of flower
nectar to maintain their own energy, male bees do not actively collect pollen and have
little value as pollinators.
51
Biology and behaviour of Megachile
Much is known about biology of many leafcutter bees due to their importance in crop
pollination (Hobbs and Lilly 1954; Peterson et al. , 1992; Raw, 2002) and the fact that
many species accept trap-nests (Raw, 1991; Sheffield et al. , 2008). Trap nesting of bees
allowed detailed study of life-history, nest building, provisioning and egg laying behaviours
(Frolich and Parker, 1983; Kim, 1992) and association of males and females of the same
species (Sheffield and Westby, 2007).
Leafcutter bees nest in pre-existing holes in wood or other materials. The alfalfa leaf
cutter bee ( M. rotundata ) are 0.5-1 cm long and 0.2 to 0.4 cm wide. Females are larger
than males with short white hairs on various parts of the body. The abdomen of the
female is more pointed than that of the male and has a pollen carrying brush of long
white bristles on the underside called the scopa. The male bee has mandibles with a
prominent tooth that helps him cut through the leaf plug that seals his cell. The females
mandibles have smaller teeth well suited for cutting pieces of leaf that the female uses
to line her cells. Cells are made back to back in the nest tunnel. The mother lays female
eggs in the innermost cells and male eggs in the outmost. This arrangement enables the
early emerging males to chew out of their cells and leave the tunnel without damaging
female cells.
Females wait to mate until their second or third day post-emergence after which
they start building cells. Males usually outnumber females two to one, but a one to one
or even higher ratio of females sometimes occur. Males cluster in nests or other cavities
at night and their numbers dwindle after the females begin nesting. Females spend the
night in nest facing inward. They turn and face the entrance as temperatures rise in the
morning.
A total of 15 to 30 trips may be required to gather the necessary pollen and nectar to
provision one cell. Initially the mother bee will collect more pollen than nectar, later
increasing the amount of nectar collected until the final ratio consists of around twothirds nectar to one-third pollen. Under warm, clear conditions with unlimited forage, a
bee may visit upto 25 flowers a minute and complete a single cell in five hours. Depending upon the length of the tunnel, 8 to 12 cells may be constructed in a single cavity.
When the tunnel is nearly filled with cells, the bee will then collect 10 to 50 circular
pieces of leaf which are deposited individually into the nest entrance. These circular
pieces are cemented together forming a solid plug which is flush with the hole entrance.
This plug serves as a barrier against rain, predators and parasites. Under favourable
conditions a female bee may finish two to four tunnels in her life time with an average of
around 30 eggs; although 50 or more eggs have been documented in some cases. Males
live for 3-4 weeks. Females can live for 5-6 weeks but probably less than 4 weeks under
field conditions.
Leafcutter bees as pollinators
Leafcutter bees can be obtained by trap-nesting wild populations. To do this, nests
are set out in United States in the early spring in locations that have good numbers of
52
wild bees, then the nests are removed in the fall. Ideal locations to place nests are on
wooden farm structures adjacent to large visual landmarks and near ungrazed pasture
with sufficient flowers to support wild populations of bees. Nests can be hung inside of
open sheds and garages or on south and east facing walls. In all cases the bee nests
should be shielded from rain and direct sunlight. More commonly bees are acquired as
loose cells from producers. Loose cells are normally stored in feed sacks and sold by
the gallon. A gallon of loose cells may not be an actual gallon by volume, but rather is a
measurement designating a quantity of approximately 10,000 dormant bees. Received
o
loose cells should be stored between 1.7 to 4.4 C in a dry location with approximately
50 per cent relative humidity. Storage areas should be free from rodent s. In case loose
cells are stored in plastic or an air-tight container, the container should be opened periodically to allow fresh air to enter and to prevent the growth of mold.
Requirements of bees for pollination
Recommended leafcutter bee densities wary from crop to crop and area to area. A
range of 5000-10000 female bees per acre was once recommended in United States
which increased to 14000 due to decline in natural populations. Generally 10000 to
20000 female bees per acre are being used for pollination of alfalfa. However, canola
growers have been stocking leaf cutters at rates of around 20000 bees per acre (Fairey
et al. , 1984).
Rearing and managing leafcutter bees
Leafcutter bees readily accept artificial nesting tunnels made from a variety of materials. Management is based upon providing nesting holes and shelters in fields, protecting bees during their dormancy and activating dormant bees in time to pollinate the crop.
A summary of most common nesting materials mentioned by Peterson et al. , 1992 for
alfalfa leaf cutter bee is as under :
A solid wooden broad (120 x 15 x 7 cm) with approximately 2000 drilled holes with 5
mm diameter and 65 mm deep.
Removable back solid board - similar to above except the back can be removed to
punch out cells.
Laminated grooved board - a pair of wood or plastic boards with opposing grooves
that form tunnels when strapped together. These nests can be taken apart to remove
cells and sanitize the boards.
Polystyrene nest board-similar to laminated grooved boards, but lighter and less
expensive.
Paper nest board - like laminates or polystyrene nest boards but designed to be
used only once.
Nesting materials and bees must be housed in proper field shelters to ensure good
bee activity and propagation. Most shelters have three sides, a roof and a floor. Sheters
should be large enough to accommodate at least 60000 to 80000 nest holes. Shelters
53
should be pointed blue, yellow or green and marked with various geometric symbols to
help bees to orientate to the shelter (Richards, 1996).
Leafcutter bees can be utilized successfully under certain situations as :
Bees forage in the field where they nest. Therefore, they are less likely to visit other
crops or be killed by insecticides on neighbouring fields.
Bees have long foraging life (4-6 weeks) as compared to other solitary bees and
produce large number of offspring.
They nest in large groups or aggregation which simplifies its management and increases its effectiveness as a pollinator.
The use of leafcutting bees is compatible with the use of honey bees. Both can be
kept in the same area if honey production is desired.
Suggested Readings
Bohart, G. E. 1972. Management of wild bees for the pollination of crops. Annual Review
of Entomology 17 : 287-312.
Keith, S. Delaplane and Daniel, F. Mayer. 2000. Crop Pollination by Bees . CABI
Publishing pp. 105-117.
54
BIOECOLOGY AND MANAGEMENT OF ALKALI BEE
H. D. Kaushik and Sunita Yadav
Project coordinating Unit, AICRP on Honey Bees & Pollinators
CCS Haryana Agricultural University, Hisar 125 004
The alkali bee, Nomia spp. (Hymenoptera : Halictidae) has been known for many
years to be a highly efficient and effective pollinator of alfalfa, particularly in western
countries of the world where these bees are used in large-scale pollination of legume
crops (Bohart, 1971). It is a highly gregarious solitary bee that nests in large numbers in
saline soils with a silt loam or fine sandy loam texture. A solitary species is one in which
the female prepares and provisions the cell, deposits the egg, and then seals the cell
completely unassisted. More than one cell may be constructed, but only one at a time.
After the cell is sealed, no further attention is given it, and the adult may die within a few
days. observed that wild bee populations actually increased at least in the eastern half
of the United States because of i) opening up of forested areas, which created more
favourable conditions for bees, ii) paving highways, which concentrated moisture along
roadsides, iii) introduction of weeds upon which the bees forage, iv) growing numerous
crops upon which the bees forage and v) bringing desert areas into bloom (with irrigation). The world's only intensively managed ground-nesting bee, the alkali bee ( Nomia
melanderi Cockerell), has been used for >50 years as an effective pollinator of alfalfa
( Medicago sativa L.) grown for seed in the western USA (Cane, 2007).
Life Cycle and Habits
Alkali bees are nearly as large as honey bees. They are black, with iridescent copper-green stripes across the abdomen. The male bee has much larger antennae than the
female. Gregarious bees are solitary individuals that endeavor to nest in close proximity
to each other and alkali bee (Nomia melanderi ) belongs to this category. The adult bees
emerge from late June to late July, depending upon the location and season. The males
appear a few days ahead of the females. Before emergence, each bee is confined to its
natal cell for 3 days as an egg, 8 days as a growing larva, 10 months as a full grown
dormant larva, 2 weeks as a pupa, and several days as a hardening, maturing adult.
During the approximate 1 month of her active adult life, the female constructs, provisions, and lays an egg in each of 15 to 20 cells (Johansen & Mayer, 1982).
Mating occurs during the 3 days the entrance tunnel is under construction, usually
during the first day. The males patrol back and forth over the nesting site, and they will
mate with any number of females; however, they rarely bother a mated female after she
becomes actively engaged in constructing the nest. About the third day after construction starts, the first cell is completed. Pollen is then collected and formed into a pellet in
the cell, an egg is laid on the pollen, and the cell is immediately sealed by a spiral
ceiling and a soil plug. After that work is started on the next cell, and no further attention
is paid to the last one. Thereafter, the daily routine consists of fashioning another cell off
the main tunnel, providing it with a pollen ball, depositing the egg and sealing the cell.
About one cell is completed each day (Bohart and Cross, 1955). Usually only one nest
55
is prepared and provisioned by a female. There is usually only one generation a year in
the intermountain States, but in California two and sometimes three generations appear
from May to September.
The development and adult emergence patterns of the alkali bee, Nomia melanderi
(Cockerell, 1906) from diapausing pre-pupae for both laboratory and field reared individuals are compared. Males from both rearing conditions emerged approximately four days
before females. Laboratory reared males began to pupate after 800 cumulative degrees
centigrade (cdc) and 50 per cent had pupated when 1200 cdc was reached. Female
pupation began about 900 cdc and 50 percent had pupated when 1300 cdc was reached.
Both male and females continued to pupate up to 1800 cdc. The field pupation rate was
linear and did not show the sigmoid curve of the laboratory pupation rate. However, 50%
pupation for both field and laboratory reared alkali bees was approximately the same at
1300 cdc (Rust, 2007).
It builds individual nests in the ground as many as 100 nests per square foot of soil.
Being gregarious, alkali bees may construct 100,000 or more nests in an area 40 x 50
feet. Nesting sites with an estimated 200,000 nests have been reported by Bohart, 1952.
The nest, a 10 mm (0.4 inch) vertical tunnel, may extend 10 inches below the surface
but is usually only 3 to 5 inches deep. There may be 15 to 20 cells usually arranged in
a single comb-shaped cluster. Each cell is an oval cavity, slightly larger than the main
tunnel, about one-half inch long, lined first with soil and then with a waterproof transparent liquid applied with the bee's glossa. Each cell is provisioned with a 1.5 to 2 mm oval
pollen ball, made up of 8 to 10 bee loads of pollen mixed with nectar. The soil removed
from the tunnel is dumped at the tunnel entrance to form a conical mound 2 to 3 inches
across.
Bee forages and feeding characteristics
Alfalfa nectar and pollen constitute the primary source of food for most female alkali
bees. They visit a few other plant species, for example, clovers, mint, onions, Russian
thistle, salt cedar, and sweet clovers. In alfalfa seed producing areas, however, most of
the nests are provisioned with nectar-moistened pollen balls derived from alfalfa (Johansen
and Mayer, 1982).
While foraging, alkali bees do not trip the alfalfa blossoms as rapidly as do the
leafcutter bees, but almost every blossom they visit is tripped. Because females visit
large number of flowers, they become highly effective. Bohart (1952) stated that two
large nesting sites in Utah (USA), one of which had an estimated 200,000 nesting
females, provided good pollination for the alfalfa-seed fields within a radius of at least 2
miles. The males visit flowers for nectar only and only occasionally trip the flowers. The
time of day that wild bees forage differs with the species involved. Those that feed only
at dawn are referred to as matinal bees. Crepuscular bees feed both at dawn and near
dusk. A few species are nocturnal in their foraging, but the great majority feed when
the sun is shining, because that is when the majority of the flowers are open.
By comparison, the alkali bee ( Nomia melanderi ) may forage 4 or 5 miles from its nesting site (Stephen, 1959); whereas the alfalfa leafcutter bee ( Megachile pacifica) usually
forages within only a few hundred feet of the nest.
56
An alkali bee female trips at least 95 per cent of the lucerne flowers as she gathers
pollen for her nest. Under good conditions, each female will trip about 25,000 lucerne
flowers during her lifetime which translates to 1/5-½ lb (91-227 g) of clean seed.
Females tend to forage within 1 mile (1.6 km) of the nest, although they have been found
up to 7 miles (11 km) from the nest (Johansen & Mayer, 1982). Kulkarni and Dhanorkar
(1998) reported that honey bees as main pollinating agents in niger followed by solitary,
alkali and carpenter bees.
Nesting sites or beds
Although alkali bees are solitary, individuals make nests near each other (Wright,
1997). There are certain basic requirements of an acceptable bed. It must have a moisture supply capable of rising to the surface. This usually requires a hardpan layer a foot
or more below a porous soil that tends to hold the moisture and permits its movement
from the source of supply to the surface. Conditions should permit rapid drainage of
surface water. The under layer should range in texture from a silt loam to a sandy loam
with no more than 7 percent clay-size particles. The surface should be firm but not have
a hard crust. If some salt does not appear on the surface, about 1 pound of salt per
square foot of surface should be raked into the first 2 inches. This seals the surface
layer and thus slows down evaporation.
The bed should be kept relatively free of weeds. It should not be flooded during the
active bee season or excessively disturbed by livestock or vehicles. When bee beds are
constructed by alfalfa seed growers, about 3 feet of soil is removed from the selected
site. The flat-bottomed excavation is then lined with 0.006-inch plastic film. The excavation is backfilled with an inch of soil, a 10-inch layer of gravel, and 2 feet of appropriate
soil. Salt is usually added to the surface as mentioned above. Water can be supplied
through a piece of tile that extends from the gravel bed to several inches above the
surface.
Social or semisocial behavior in nomiine bees is here reported for the first time from
India (Batra, 1964). In Nomia capitata and perhaps in N. oxybeloides, presumed sister
bees share cell clusters and cooperatively provision the same cells. Unlike other primitively social bees, the sisters simultaneously forage and oviposit. There is no apparent
inhibition of the oviposition of daughters, although their nest-founding mother or perhaps
an older sister appears to stay in the nest and continue to oviposit. Nesting behavior and
nest structure of Nomia capitata and N. oxybeloides are similar; cells are vertical and
clustered. In contrast Nomia nasicana makes horizontal cells scattered along the main
burrow.
Qualities of good nesting sites
There are three important factors determining the quality of alkali bee nesting sites,
whether natural or managed i) soil moisture; (ii) soil composition and texture; and (iii)
vegetation (Johansen and Mayer,1982).
Soil moisture
Soil must be moist down to at least 12 inches (31 cm). Soil moisture in good sites
57
varies from 8 to 32 per cent depending on soil type. Soil moisture can be measured
using a tensiometer. A reading of 15-25 centibars indicates adequate moisture regardless of soil texture. Dry nesting sites have been a limiting factor in alkali bee production.
Good natural moisture conditions are associated with shallow layers of calcareous hardpans lying a few inches to several feet below the surface. Seepage water may be subirrigated nearby nesting sites when a shelf of this impervious material lies along a river,
canal, or pond. Where this occurs, populations of alkali bees may build up naturally
with little management. Most nesting sites are man-made and require an artificial water
supply provided with shallow ditches made across or around beds, or some kind of
subsurface distribution system.
Soil composition and texture
Maintaining proper soil texture in bee beds is almost as important as providing
adequate water. These two factors are interrelated. A soil of poor texture can limit the
movement of water through the upper horizon even when water is abundant. Conversely,
soil of excellent textural qualities is of little value where water is in short supply. Proper
soil texture encourages excavation by bees and allows continuous capillary flow of subsurface water towards the surface, replacing water in the upper layers at a rate equal to
or slightly greater than the rate of evaporation. The surface should not be crusty or fluffy.
The goal of soil texture management is a moist and moderately compact upper soil
horizon which persists throughout the active bee season.
Uniform soil moisture and good nest digging conditions depend largely on the percentage composition of clay, sand, and silt, with clay preventing capillarity at levels
greater than 25 per cent. Soils high in sand (45-80%) are difficult to seal, and excessive
water movement and evaporation may occur. The likely result is a wet bed with a dry,
powdery surface. Sandy beds become quickly populated with maximum number of nesting
bees but do not maintain good populations for more than 3-4 years. The best alkali bee
beds have soil classed as silt loams with 2-6% fine silt and 42-68% coarse silt. They
contain 13-24% clay and 10-40% sand.
Vegetation
The surface should be essentially bare with sparse vegetation. Plants use up soil
moisture and bees prefer to nest in bare ground. Nevertheless, a little vegetation can
help protect bees from summer rains and reduce wind erosion.
Establishing bees
The final and critical step in developing a new bed is establishing a population of
bees. This may be easy if the new site is close to existing beds which support large and
growing bee populations. Surplus bees from these established sites will move to the
freshly prepared surfaces which are relatively clear of vegetation. If a new bed is isolated
from existing populations, bees must be introduced to the area either as adults or as
immature. Several methods have been developed for transplanting/ transferring bees
from one location to another, sometimes over great distances.
Investigators in Utah successfully transferred adult females to new beds (Parker and
58
Potter, 1974). They captured bees at existing sites, anaesthetized them with carbon
dioxide, and transported them in an ice chest to new locations. Starter holes were punched
in the bed surface to encourage nesting. Bee nesting was optimized when females were
released after sunset, the time at which they usually dig in for the night and become
established at a site. Many adults flew away when they were released in the morning
and afternoon. Transfer success was best with newly-emerged females.
The most successful and widely-used method is to transplant cores or blocks of soil
containing prepupae. This must be done in spring before the immature transform into
pupae or adults. Cores are placed on pallets and loaded on to a truck for transport.
They should be covered with moist canvas or burlap if they are being transported long
distance. In this manner, several thousand cores can be moved by one semi-truck.
When the cores arrive at a new site, they should be buried in 12 inches (30 cm) trenches
and puddle in with sparing amounts of water. Soil at the new site should be properly
prepared before the transplants are installed. It should have about the same moisture
content as the core. Cores should be installed in straight lines at least 4-6 inches (10.215.2 cm) apart to ensure good soil moisture. They should never be stored for any length
of time before burying them; this increases the risk of desiccation and decreases the
viability of prepupae.
Measurement of bee density
The number of foraging female bees required in field is not fully known, but it should
probably exceed 3000 per acre (7410 /ha) in lucerne. It is easier to measure bee densities by assessing nest concentration. A good natural nesting site will average about 1
million nests per acre (2.5 million /ha). One acre (0.4 ha) of bed with this number of
nests should provide for 1000 lb of clean seed per acre (1120 kg/ ha) on 200 acres (81
ha) of lucerne. The maximum population in artificial beds is about 5 ½ million nest per
acre (13.6 million /ha) (Johansen &Mayer, 1982).
Suggested readings
Batra, S. W. T.1964. Social behavior and nests of some nomiine bees in India
(Hymenoptera, Halictidæ). Insectes Sociaux , 13 (3) : 145-153.
Cane, J. H. 2008. A native ground-nesting bee (Nomia melanderi ) sustainably managed
to pollinate alfalfa across an intensively agricultural landscape. Apidologie ,
39 : 315-323.
Johansen, C. and D. Mayer. 1982. Alkali bees: their biology and management for alfalfa
seed production in the Pacific Northwest. Oregon State University Press. Corvallis.
Pacific Northwest Entension Publication , 23.
Stephen, W. P. 1959. Maintaining alkali bees for alfalfa seed production. Oregon State
College Agricultural Experiment Station Bulletin, 568 : 1-23.
59
BIOECOLOGY AND MANAGEMENT OF STINGLESS BEES
FOR CROP POLLINATION
M. Muthuraman, P. A. Saravanan, K. Vijaya Kumar and P. Priyadharshini
Department of Agricultural Entomology
Tamil Nadu Agricultural University, Coimbatore 641 003
Stingless bees are eusocial bees like honeybees. The stingless bees are the most
abundant bees on earth. Meliponini is one of the older groups of bees originated in Africa
and is distributed in all major continents probably through the mechanism of continental
drift. Generally stingless bees are not efficient in controlling nest temperature. They are
inefficient especially in raising the temperature when it is low. Hence, they are limited to
tropical and sup tropical areas. Stingless bees are small to medium sized bees with
vestigial stings. These bees are sometimes called dammer bees, as they collect dammer,
a kind of resin for construction of their nest along with wax produced from their body.
The size of stingless bees ranges from 2 to 16 mm. They cannot sting because these
bees have no venom apparatus. They show a level of social organization comparable to
that of honey bees. They have reduced wing venation and sting, which is compensated
by their stout mandibles suited for biting. Though they are stingless, they protect their
nest very effectively by biting the intruders. They get into the hairs of the intruders and
bite their skin with mandibles. Stingless bees belong to the family Apidae and are
classified under the sub family Meliponinae. Melipona and Trigona are the two important
genera classified under Meliponinae. Melipona is restricted to tropical America while
Trigona is the largest group and most widely distributed and occurs from Southern Asia
to Australia including India.
Nesting biology
Stingless bees live in perennial colonies. They often construct their nests in tree or
wall cavities. Underground nesting stingless bees are also found in Nagaland. The nest
is usually made up of five parts viz., brood cells, storage pots, involucrum, batumen and
an entrance. The nest is built using a special building material viz., cerumen which is a
mixture of wax secreted from the wax glands on the abdomen and resin which is collected from plants. Brood comb may either be multi layered or made up of brood cells
arranged in cluster. Cluster type nests can take advantage of small and irregular spaces.
A small crack or hole serves as the entrance hole. It often extends from the nest as
a tube and also continues inside the nest cavity. Nest entrance is always protected by
entrance tube. The entrance hole is connected to the nest components by an internal
tube. Two types of envelopes protect the nest viz., involucrum and batumen plate. Brood
cells are wrapped around by loose wax sheets called cerumen. Batumen plates usually
made of cerumen and mud seal the extra space present inside the tree cavity. Pillars
and connectives formed of criss cross strands of cerumen are found inside the nest to
support the nest components. Pollen is usually stored in closed cerumen pots found in
clusters. Pollen pots are usually found closer to the entrance. Honey pots are usually
60
found in separate clusters. Sometimes both pollen pots and honey pots are intermixed.
The honey pots are initially open and closed after the completion of honey ripening
process. Waste and resin are stored inside the nest in waste dump and resin dump,
respectively, which are found only in stingless bees.
Developmental biology
Brood cells are either spherical or oval in shape. Stingless bees use cerumen, a
mixture of wax and resin for building brood cells. In each brood cell a bee is reared and
used only once. Brood cells are built in clusters in the advancing front of the brood area.
The empty brood cells are discarded after adult emergence. The cerumen scrapped off
from the full grown larval brood cells is recycled and utilized for cell construction.The
bees develop in captivity in closed brood cells only from queen laid eggs.The larvae are
nourished through mass provisioning. A complex behavioural sequence involving queen
and workers lead to provisioning of brood cells with larval food and laying of eggs in such
provisioned cells. Provisioning occurs only after the arrival of queen. Drumming of workers by queen results in food regurgitation by workers in the cells and oviposition takes
place. Operculation of the cells occurs after oviposition. The incubation periods of the
immature stages of workers of T. iridipennis viz., egg, larva, prepupa and pupa last for
two, one, one and three weeks, respectively.
The mature drone brood cells are similar to worker brood cells and are admixed with
worker brood cells. It is also difficult to sex the larval brood cells of worker and drone as
they are almost similar in size and shape. It means that both worker and drone larvae
are fed with the same quantum of brood food. Further, bee emergence from pupal brood
cluster occurs in one stroke. Hence, it is likely that the developmental period of drones
may be similar to that of workers.
The queen brood cells are few and are both larger and taller than worker brood cells
in Trigona. But in Melipona both the worker cells and queen cells are similar.Queen cells
are constructed especially during swarming season.The quantum of food provided to the
larvae plays a crucial role in caste determination. The larvae fed with more amount of
larval food develops into queen. Sudden loss of queen in a queen right colony triggers
the construction of emergency queen cells for the purpose of requeening the colony.
Gynes emerge from emergency queen cells within 50 days.
Social biology
In stingless bees the swarms are always led by gynes.They establish new daughter
nests nearer to the mother nest. Swarm cluster formation does not occur at the time of
swarming. Further, the separation of daughter colony from mother colony is gradual. The
daughter colony maintains its contact with filial nest for a long time. Drones form both
nest associated and non nest associated congregations. They leave the nest after
attaining sexual maturity and they never come back to the nest. Drones are able to live
outside the nest as they are capable of collecting food from flowers.
61
Colony reproduction
Colony reproduction is slow and it occurs mainly through swarming. It begins with
the selection of new nesting site by scout bees. The selected site is cleared and the
cracks are closed. Nesting materials are shifted from mother nest. Various nest components viz., entrance tube, internal tunnel and food pots are constructed. Later the food
is transported from the mother nest into newly fabricated food pots.The young queen
arrives to the new nesting site along with part of the workers. Some workers in the
swarm return back to the mother colony the next day after swarming. The males are
attracted to the newly formed daughter colony with virgin queen. The males hover around
the entrance. The mating of virgin queen occurs with male outside the nest. In young
queen abdomen is not inflated. Brood cells are constructed and the mated queen lays
eggs in the brood cells. The swarms are led by new queens. Swarm cluster formation
does not occur. Colony separation is gradual. The stingless bee queen flies out from the
colony only once in her life time. She mates only once with a single drone. After mating
her abdomen enlarges and she looses the ability to fly. In gravid queen the abdomen
becomes inflated.She begins to lay eggs. As a result, she always remains in the old
nest.In stingless bees the swarms are always led by gynes and they establish new
daughter nests nearer to the mother nest. The daughter colony maintains its contact
with filial nest for a long time.
Meliponiculture
Meliponoculture is the science of keeping and managing stingless bees. In some
parts to Kerala meliponiculture is practiced as backyard bee keeping mainly for honey
production where stingless bees are kept either in bamboo nodes or mud pots or box
hives. Stingless bees are also kept both in traditional log hives and box hives by Naga
tribals in Nagaland.
Meliponiculture can be started by hiving feral colonies either from wall cavities or
tree cavities.The nest is dissected out by removing the stones or by splitting the branch.
The various nest components are transferred into the hive.The queen is searched and
found out in the brood nest region and transferred into the box hive by using a camel hair
brush smeared with honey. Resin smeared entrance easily lures all the dislocated workers back into the box hive.Later the hive has to be shifted to meliponiary after dusk.
Strong colonies dwelling inside the wall cavities can be lured into box hives or pot
hives by providing extra space outside the nest through a process called eduction. If
enough additional space is not available for the feral colony inside the cavity to expand
the nest, the colony moves into the hive affixed to the nest. This method takes much
time to establish a new colony.
New colnies can be easily produced by splitting populous colonies by horizontal
splitting method. Two chamber hives having an equal sized bottom and top are suited for
splitting. A populous colony which has grown well and occupied both the chambers are
ready for division. To the bottom chamber an empty lid is given and for the top chamber
an empty bottom is given. The queenless split kept in the original site and the queenright
62
split is shifted to a new location 15m away from the original site. A new queen will
emerge and start egg laying after mating in the queenless split. Apperance of advancing
front in the queenless split is an indication of successful splitting.
Management of stingless bee colonies
Keep the colonies in shade to protect the nest components against the scorching
effect of sun.
Prevent entry of rain water into the hives to avoid mould growth and subsequent
colony desertion.
Use a mylar film sheet of suitable size as an inner cover for the box hive to facilitate
easy hive inspection.
Provide artificial feeding with honey bee honey or sugar syrup (1 : 1) in mud lamp
feeder during dearth period especially when adequate honey reserve is not present
in the hive which is needed for proper growth of the colony.
Provide ready to emerge pupal brood and artificial feeding to strengthen weak
colonies.
Provide either ripe queen cells or honey smeared queen/gyne to orphan colonies for
requeening
Provide either advancing front having egg\larval brood and pupal brood or advancing
front having larval and pupal brood for requeening queenless colonies
Remove the spider webs found in or near the hive to protect the colony against
spiders
Seal the inner lid tightly with resin to deny access for ants
Remove affected pollen pots and brood cells to prevent the spread of storage mites
infesting pollen pots.
Stingless bees for crop pollination
Floral choice of stingless bees
Stingless bees are generalist flower visitors. They visit a broad range of plant
species.
They prefer small flowers, dense inflorescence, flowers with long corolla tubes that
are wide enough for the bees to enter and white or yellow coloured flowers.
Stingless bees are opportunistic foragers. They respond well to heavy flowering.They
become much busier as the workers take advantage of the temporary abundance of
pollen.
Natural vegetation provides nesting sites and other food for the bees. The more
natural vegetation around the greater the bee population.
Stingless bees are better pollinators
Stingless bees may be better pollinators of some crops than honey bees.They
They thrive much better in tropical areas.
63
Use of native species can help to protect them.
They can be effectively used for green house pollination because of their limited
foraging distance and the owner gets the maximum benefit.
Advantages of stingless bees over honey bees
Stingless bees are generally harmless to human and domesticated animals. So they
can be safely kept close to a house and handled by people who are allergic to
honey bee stings.
Small size of stingless bees allows them to have access to many kind of flowers,
whose opening are too narrow to permit penetration by other bees. Hence, they
co-exist peacefully with commercial bees.
The foraging range of stingless bees is shorter than commercial bees. Hence, they
can be very well utilised for pollination.
Stingless bees are able to forage effectively in glasshouse. Honey bees usually do
not forage well in confined spaces. However, if condensation develop s inside the
glasshouse panels they get trapped.
Stingless bee colonies are not able to swarm away as honey bees because the
mature stingless bee queen is unable to fly. Stingless bees can, however, set up a
new nest when the old one is full, but part of the colony always remains in the
original location.
Stingless bees are resistant to the diseases and parasites of honey bees. They are
not affected by the virus diseases of honey bees or mites. However, stingless bees
have their own natural enemies but these are not shared with honey bees and are not
very serious.
Desirable attributes
Polylecty: The workers from a colony can visit many different types of plants. This
behaviour, called polylecty, enables a colony to potentially pollinate many types of
plants. In addition, they can also quickly adapt to new plants that they have not
known before.
Floral Constancy: Each individual worker on a trip usually visits only one plant species. This behaviour, called floral constancy, makes these bees efficient pollinators
because each bee only carriers pollen between the flowers of one plant species.
Domestication: Stingless bee colonies can be domesticated. They can be hived,
inspected propagated, fed, re-queened, controlled for natural enemies, opened for
extraction of honey and otherwise managed. The potential of stingless bees for crop
pollination is enhanced by the ability to transfer colonies into artificial hive. These
hives can be propagated so that growers do not to depend on natural populations.
Hives can also be transported wherever needed for pollination.
Perennial nature : Stingless bee colonies live for a long time. They do not have to be
restarted.
64
Adaptability : Stingless bee colonies are active over a wide range of climatic
conditions and if the climatic conditions become unsuitable, the colonies can be
moved to better area.
Hoarding food: Large food reserves are stored in stingless bee nests so the bees
can survive for long periods when food is scarce. The workers will also collect more
nectar and pollen than their current need. This can result in huge numbers of bees
visiting a particularly good food source, resulting in intensive visitation of preferred
flowers.
Shorter foraging distance: Stingless bees have short flight range. Hence, their
importance is increased in using them for green house pollination.
Forager recruitment: Scout bees in a colony find new flowers for the colony to use.
Middle aged foragers function as scout bees. They return to the hive and communicate the location of the flowers to other worker bees. These workers can then quickly
reach the flowers and forage upon them. If the flowers continue to be productive,
even more workers will be brought in. The behaviour, called forager recruitment,
allows large numbers of worker bees to quickly find a good food source.
Communication mechanisms: Different communication strategies are used by the
scout bees for sharing the information about the discovery of a floral patch to the
nest mates. The returning foragers may produce a weak or strong sound and run in a
zig zag manner while passing the nectar to the hive bee which make the nearby
bees to repeat their sounds and the whole colony buzzes and the responsive bees
leave out for foraging due to mass sound production. Foragers of T. postica mark an
odour trail between the food source and the colony with their mandibular gland secretions. Stingless bee foragers have to make foraging decision based on information that may come from two different sources: information learned and memorised
through their own experience (internal information) and information communicated
by nest mates or directly obtained from their environment.
Crop pollination
Stingless bees are important pollinators of crops in tropical and subtropical parts
of the world. There are many crops for which stingless bee pollination has not been
thoroughly investigated. Neglect probably reflects the lack of knowledge rather than lack
of importance.More than 1000 plant species are cultivated in the tropics for food
beverages, fibre, spices, and medicines. The pollinators of most of these crops are not
known. However, stingless bees are known to visit some of these crops. No crop is
known to be dependent on stingless bees exclusively for cross pollination. But the yields
of many crops benefit greatly from their pollination services provided by stingless bees.
The crops for which stingless bee pollination can be valuable in India are mango coconut and chow chow.
Chow chow : Chow chow is a subtropical vegetable. It has separate male and
female flowers. Stingless bees are common and efficient pollinators of chow chow flow65
ers in Costa Rica. Pollination by stingless bees positively influenced the yield and the
quality of chow chow also in India
Coconut : Honey bees and stingless bees are effective pollinators of coconut flowers through out the tropics. Stingless bees are found to be very active on dwarf coconut
palm. Coconut flowers grow in a cluster which include both male and female flowers.
Studies overseas and in India showed that stingless bees visit both male and female
flowers. Most bees visiting female flowers in search of nectar carry loads of coconut
pollen from previously visited male flowers and thereby assist in pollen transfer.
Yields are also higher when hives of honey bees and stingless bees are kept in coconut
plantations.
Mango : Stingless bees are the most common insects visiting mango flowers in
Australia and Brazil. In Australia, Trigona bees are the most efficient pollinators of mango
as they leave many pollen grains on the stigma after a visit. This efficiency is due to the
large amount of pollen carried on the bees' bodies and the close contact they make with
the stigma. Furthermore, Trigona bees fly more frequently from one tree to another tree
and thus are probably the most effective cross-pollinators. Honey bees are not strongly
attracted to mango flowers and are only occasionally observed. Files are the most
common visitors to mango flowers in many parts of the tropics and are probably also
efficient pollinators. Thus, stingless bees and flies are the most important pollinators of
mango.
Table 1.
S.No
Crops that might be pollinated by stingless bees
Crop group
Crops
1.
Fruits
Peach, Plum, Pear, Guava, Citrus, Litchi, Straw berry,
Jack fruit, Bread fruit
2.
Vegetables
Cucumber, Water melon, Squash, Bitter gourd, Sweet
pepper, Egg plant, Onion
3.
Pulses
Pigeon Pea
4.
Oil seeds
Sun flower, Castor, Niger
5.
Spices
Cardamom, Coriander
6.
Trees
Indian jujube, Subabul, Soap nut, Kapok, Tamarind
Sago palm, Rubber, Eucalyptus
Strawberry : Imported stingless bees have been evaluated in Japan for pollination of
strawberries in glass houses. Japan has no native stingless bees but they have
imported colonies of stingless bees from Indonesia and Brazil. One study found that the
stingless bees foraged much more effectively in the confined space of glasshouse than
honey bees did. This study also found that to produce high quality strawberries,
11 honey bee visits or 30 stingless bee visits were required per flower. However, another
66
study showed that only four stingless bee visits producesd well-formed fruits.The following is the list of crops grown in India visited and occuasionally or partiallt by stingless
bees.
Pollination of non-crop species
Stingless bees are efficient pollinators of non crop- species in natural habitats. They
play a vital role in sustaining the forest flora, epiphytic orchids and rare aquatic plants.
In some cases stingless bees may do harm for some crops by removing nectar or pollen
without pollinating the flowers. This makes the flowers less attractive to the other
insects or birds which are the effective pollinators of that crop. In some extreme cases
stingless bees may cause more serious harm. Stingless bees have been reported to
damage the flowers of the canola crop and drive away the effective pollinators of passion
fruit.
Suggested Readings
Devanesan, S.; Shalaja, K. K.; Rakhee, M.; Bennet, R. and Premaika, K. S. 2003.
Morphometric characters of the queen and worker of stingless bees T. iridipennis
Smith Insect Environment 9 (4) : 154-155.
Fletcher, D. J. C. and Crewe, R. M. 1981. Nest structure and thremoregulation in the
stingless bee. T. denoiti (Hymenophera : Apidae) J. Entomol Soc. South Africa
44 (2) : 183-196.
Micher, C. D. 1974. The Social Behaviour of the Bee : A Comparative Study. Harvard
University Press, Cambridge.
Micher, C. D. 2000. The Bees of the World . Meliponinae. pp. 779-805.
67
CONSERVATION, AUGMENTATION AND UTILIZATION OF
WILD BEES IN CROP POLLINATION
D. P. Abrol
Division of Entomology,
Sher e Kashmir University of Agricultural Sciences & Technology, Jammu
Insect pollination of agricultural crops is a critical ecosystem service. Fruit,
vegetable or seed production from 87 of the 115 leading global food crops depends upon
animal pollination (Klein et al. , 2007). The value of insect pollination for worldwide agricultural production is estimated at 153 billion, which represents 9.5% of the value of the
world agricultural production used for human food in 2005 (Gallai et al. , 2009). The area
cultivated with pollinator-dependent crops has increased disproportionately over the last
decades, suggesting that the need for pollination services will greatly increase
in the near future. The Apis mellifera has occupied dominating position in commercial
pollination around world because this is highly social bee. But of the other hand wild
bees are also valuable pollinators. We have always under evaluated their contribution
perhaps because of our limited insight into their behaviour mechanism for nesting. The
other reason may be that we are more reliable on the easily manageable honey bees
which provide by-products also. But today the modern beekeeping suffers from a magnitude of problems, including parasitic mites, honey bee diseases, unability of honey
bees to work at low temperature and adverse climatic conditions. These difficulties
threatens the honey bees general utility as an agricultural pollinator (Torchio, 1990) This
contributes to the concern to beekeepers, growers of insect-pollinated crops, and policymakers over recent widespread declines in honey bee populations (Colony Collapse
Disorder).
For agricultural as a whole the diversification of pollinaton assemblages for crops is
clearly important. Wild and domesticated non-Apis bees effectively complement honey
bee pollination in many crops. Examples of management of non-Apis species for agricultural pollination include the use of bumble bees, primarily for the pollination of greenhouse tomatoes, the solitary bees Nomia and Osmia for the pollination of orchard crops,
Megachile for alfalfa pollination, and social stingless bees to pollinate coffee and other
crops. The value of the alfalafa leaf cutting bee M. rotunda (F.) as a better pollinator than
honey bees for alfalfa has been clearly demonstrated by Richard, 1987. he concluded
that the real impact of introduction of Megachile bees stating that alfalfa seed yield
increased from 50 kg/ha to 350 kg/ha and with more careful handling it can be raised
upto 1000 kg/ha.
There are about 19,000 described species of bees in the world (Linsley 1958) and,
with the exception of one species, Apis mellifera L., the domestic honey bee, all of them
are grouped under the general term "wild bees".
68
Short-tongued bees :
Family
Important genera
Andrenidaea
Andrena, Panurginus, Perdita, Pseudopanurginus
Colletidae
Colletes, Hylaeus
Halictidae
Agapostemon, Dufournea, Halictus, Nomia
Melittidae
Hesperapis, Melitta
Long-tongued bees:
Anthophoridae
Anthophora, Melissodes, Nomada, Xylocopa
Apidae
Apis, Bombus, Euglossa, Melipona, Trigona
Megachilidae
Anthidium, Lithurgus, Megachile, Osmia
The term "wild bee" is used commonly for all bees except honey bees in the genus
Apis. Bees generally are distinguished from other flying hymenopterous insects by their
characteristic plumose body hairs. Bees are of many sizes, shapes, and colors. Some
of the smallest bees, Perdita, are less than 3 mm; whereas the largest leafcutter bee is
over 80 mm. Almost the entire range of colors is found among the brightly marked bees,
including many beautiful metallic species. One can easily observe many species of
bees actively visiting flowers for nectar and pollen or engaged in the processes of constructing nests. According to an estimate there are at least 30,000 species of bees in
the world. This number of species is more than all the fish, bird, and reptile species
combined (Bohart, 1972).
Most bee species construct either single or complex nests underground. Some make
earthen, leaf, or resin nests on rocks and plants. Other bees make or utilize crevices in
rocks or plant stems, insect borings, and plant galls for their nesting sites. Most bees
live a solitary existence-each female after mating locates and builds her nest without
the aid of other bees, and usually at a distance from her sister bees. However, some
bees are quite gregarious and nest close to one another, sometimes in dense populations of up to a million nests in a few acres of soil. Some bees prefer to nest at the same
site year after year, but others relocate their nests each season. A small percentage of
our wild bees are social or semisocial; that is, there is a division of labor among the
bees occupying a single nest (Michener, 2000).
Value of wild bees as pollinators
One cannot easily determine the figure on the value of wild pollinators, simply because total impact on the environment is not known. Studies on the impact of each
pollinator species on fruit or seed production of our major crops is almost nonexistent.
The reproduction of wild flowering plants is often taken for granted to aid in maintaining
soil moisture and fertility, and to provide food not only for wild life but for our domestic
livestock as well. How many billions of dollars are these benefits worth? It is easy to
document the value of crop species visited by bees, but here again the importance of
wild bees as crop pollinators has been neglected. It has long been the general
consensus that honey bees adequately pollinate crops and there is little need for wild
bees. Unfortunately, it is not true since adequate research on the economic benefits of
69
wild pollinators has not been done. Interestingly, the research completed on the few wild
pollinator species has revealed relatively higher returns compared with its investment
costs.
The dependence on one species for crop pollination sometimes creates problems. It
seems wise to make greater efforts to study, conserve, and try to manage as many
species of wild bees as possible. There are several crops that are under pollinated by
the honey bees, either because the bees are not physically adapted to pollinate them or
the crops are not attractive to honey bees. Some of our most important crops, valued at
billions of dollars, are in this category. These crops are alfalfa, soybeans, cotton, vegetable seed, and sunflowers, each of which is adapted to specific types of pollinators.
Recent research on the utilization of several species of wild bees as crop pollinators is
just beginning to indicate some of their economic benefits, e.g the alfalfa leafcutter bee.
The alkali bee was the first wild bee to be utilized as a crop pollinator in the United
States beginning in the early 1950's. Since that time, the alfalfa leafcutter bee and the
blue orchard bee have been domesticated as crop pollinators.
Diversity of wild bees
Friese (1923) estimated that out of 20,000 species of bees (Superfamily : Apoidea),
only four species of honeybees (now nine) and 300 species of stingless bees (Family:
Meliponinae) live in the permanent perennial colonies. The majority of the bees are solitary where a female constructs a nest consisting of one or more brood cells stocked
with nectar or pollen that provide food for the larvae that will emerge from the eggs she
deposits just before the sealing of the cell. In general, two thirds of the bee fauna is
comprised of the solitary bees (Michener,1965; Linsley,1958; Bingham,1897; Batra,1977).
Michener (2000) apprehended 16,325 species of bees, grouped under 425 genera (Table
1). The taxa found in whole of the world were reorganized under 7 families. Still much
needs to be known from different regions of the world about the existence of different
species of solitary bees, more particularly, from the Oriental region.
Why wild bees management
The expensive need for insect pollination in modern agriculture has made bees a
vital factor in crop production. To most people, the word bee suggests only the common
honeybee, perhaps also bumblebees; but the bees are in fact a super family of the order
Hymenoptera, containing an estimated twenty thousand species. They are in fact a
group of flower-visiting wasps termed as bees that has abandoned the wasp habit of
provisioning nests with insect or spider prey and instead feeds its larvae with pollen and
nectar, collected from flowers or with glandular secretions ultimately derived from the
same sources. They are a large and diversified group, considered to be consisted of
nine families (Michener, 1974). Except in certain Colletidae which carry pollen with nectar in the crop, the structures used for carrying pollen consist of scopal hairs having
various locations and arrangements. One such group is the Masaridae, a family of wasps
closely related to the Vespidae and in the superfamily Vespoidea. The other group of
wasps which abandoned predation as a source of larval food was from an entirely different source than the masarids, namely the wasps of the superfamily Sphecoidea. From
this group arose the bees. Bees, entirely dependent on flowers for food, could not have
arisen before the appearance of the angiosperm plants.
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Table 1.
Families, subfamilies, principal tribes, and the distribution of bees
(superdfamily Apoidea) (Based on Michener, 1974)
S.No. Family
1.
2.
3.
4.
5.
6.
7.
8
9.
Subfamily
Distribution
Colletidae
Oxaeidae
Halictidae
Worldwide
New world
Dufoureinae`
Holarctic; African andOriental regions; Chile
Nominae
Old world tropics ; South temperate regions;
Holarctic
t. Augochlorini South and central America, some in Canada
t. Halictini
Worldwide but less abundant in subtropics
Andrenidae
Andreninae
Chiefly Holarctic some in Africa and S.America
Panurginae
Africa, Eurasia, New World
Mellitidae
Ctenoplectrinae Paleotropics
Macropidnae
Holarctic
Melittinae
Holarctic, Africa
Dasypodinae
Holarctic, Africa
Fidelidae
S. Africa and Chile
Megachilidae Lithurginae
Worldwide (tropical and warm regions)
Megachilinae
t. megachilini
All continents
t. anthidini
All continents
Anthophoridae Nomadinae
Worldwide
Anthophorinae
t. Exomalopsini Neotropics
t. Ancylini
Mediterranean and eastward into Asia
t. Tetrapedini
Neotropics
t. Melitomini
Western hemisphere
T. Canephorulini S. America
t. Eucerinodini S. America
t. Eucerini
All continents(except Australia)
t. Anthophorini Worldwide
t. Centridini
Americas (tropical and warm parts)
Apidae
Bombinae
t. Euglossini
Neotropics
t. Bombini
Holarctic
Apinae
t. Meliponini
Tropics worldwide
t. Apini
Eurasia and Africa
introduced to all parts of the world)
71
How early bees arose from the sphecoid wasps is unknown; it might have
been as late as the middle Cretaceous since angiosperms also became the dominant
vegetation in middle Cretaceous times. Primitive angiosperms had relatively shallow
flowers, such as can be used as pollen and nectar sources by short-tongued insects,
including many beetles, wasps, and the short-tongued bees. The first five families, listed
as Colletidae. Halictidae. Oxaedae, Andrenidae and Mellitidae are characterized by usually short mouthparts and are often grouped as the short-tongued bees. The other four
families Fidelidae, Megachilidae, Anthophoridae and Apidae are classified as long tounged
families, all are equipped with elongated glossae, maxillary galeae and basal segments
of the labial palpi forming the sucking apparatus for taking advantage of nectar sources
with deep tubular flowers. Flowers with deep corolla tubes probably arose in coEvolution with their principal pollinators. The legume crops and their pollinators such as
alfalfa-megachilid constitute an important example. There is close relationship between
bumble bee species and their major plant hosts accordingly to their length. The worldwide distribution of these bees and their remarkable ability for proliferation are the
results of their higher degree of adaptability (Stephen et al., 1969, Michener, 1974).
In many colonies there are interrelations among individuals, such that behavior of
one influences the behaviour or development of another. All these interrelations are termed
social interactions. Feeding of a larva by a bee is an example of a social interaction. As
indicated previously, colonies of bees range from those that seem almost insignificanttwo or three bees in a burrow in the ground or in a hollow stem- to the large colonies of
the honeybees. The kinds and amount of division of labour and communication among
bees in colonies very greatly. Species are often called solitary, communal, social, and
so forth. Such terms are generally applied to the most complex type of organization
attained during life cycle of the species. In the majority of species of bees each female
makes her own nest, or sometimes several of them, without regard to the locations of
other nests of the same species,. Such bees mass-provision the cells by placing enough
pollen and nectar in each to provide for the entire growth of a larva. After oviposition, the
mother seals the cell and goes on to construct and provision another. Ordinarily she
dies before her progeny mature and emerge from their cells; therefore there is no contact between generations. Probably the majority of species of Solitary bees have only a
single generation per year, the adults emerging and flying about during a relatively brief
season, sometimes only two or three weeks. Such species pass the rest of the year in
the nest. The feeding stage of the larva is ordinarily brief, often only a few days, and
most of the year is passed in the pupal stage or as young adults either still in their natal
cells or in special hibernating or aestivating places. Some solitary bees, however,
regularly have two generations per year, for example one in spring and another in the
autumn, while others go through a succession of overlapping generations so that,
except in the spring, all stages can be found at anytime during the warmer months of the
year.
Nest aggregations occur most commonly among bees that burrow in the soil.
Aggregations of such burrows may vary from a few to 10 nests scattered that one
wonders if they constitute an aggregation at all, to small, dense clusters of nests like
72
those of Lasioglossum versatum in Kansas. Some bees that make burrows in stumps or
logs instead of soil also form aggregations. For example. one may find numerous nests
of carpenter bees ( Xylocopa ) in a single post or building. Bees mostly megachilids that
construct exposed cells of mud and other materials brought to the site sometimes also
form aggregations of nests: for example Chalicodoma muraria sometimes covers
large portions of walls in southern Europe and North Africa with masses of its cells.
Communal quasisocial and semi-social groups are so similar superficially that the
convenient collective term parasocial has been proposed for them. Parasocial colonies
are simply any colony in which the adult bees consist of a single generation, unlike the
eusocial forms in which two generations of adults are ordinarily present. A communal
colony consists of a group of females of the same generation using a single nest each
making, provisioning, and ovipositing in her own cells. In the enormous genus Alldrella,
most species are solitary, some nesting in aggregations. However, Alldrella bucephala
and A.ferox live in colonies that are probably communal. These are small colonies with
two to several females,usually of about the same age and of the same generation, cooperatively construct and provision cells. More than one bee working on a given cell. As in
communal groups, each female has enlarged ovaries and is mated, indicating that each
is an egg layer. Some species of Nomia are possibly quasisocial, although knowledge of
their colonies is inadequate (Batra, 1966a ). The best known of such species is N.
capitata from India. These are small groups which show cooperative activity and division
of labor among adult females as in eusocial groups. Polygynous young colonies of other
halictines (Vleugel 1961) are often temporarily semisocial in that division of labor develops among gynes, one becoming the egg layer or queen, the others auxiliaries or, in
effect, workers. These are family groups each consisting of one adult female and a
number of immature offsprings which are protected and fed by the adults. The mother
leaves or dies before or at about the time that the young reach maturity. There is no
division of labour among adults, as is found in semisocial and eusocial groups. Young
colonies of Bombus, before workers are produced, are subsocial; the queen progressively feeds the growing larvae in a more or less subdivided common cell. However, the
true social Hymenoptera, for which the word eusocial was coined by Batra (1966b), live
in colonies which are family groups consisting of individuals of two generations, mothers
and daughters. Usually in bees a eusocial colony contains only one queen and the bulk
of the females are workers (daughters). Division of labor, with some individuals functioning as egg layers or queens and other as workers. that is, with more or less recognizable castes occurs in both the semi social and eusocial colonies but not in the other
types of colonies.
Colonies are long-lived and sustained through periods of adversity by food for adult
as well as larval consumption, stored in the nests but in brood cells. Integration within
colonies is complex and involves a variety of behaviour patterns, pheromones and physiological adaptations that would have no obvious function in solitary forms. Aggressive
behaviour among individual of the same colony is rarely evident, nor is the egg eating
that is often associated with such behaviour. Communication concerning food sources
and at swarming time, concerning nest sites is well developed in many of
73
these bees. Larvae are fed at least in large part on glandular secretions of workers.
Populations of colonies are commonly in the thousands (upto over 60000 for Apis , 180,000
for some species of Trigona ), although some species often have colonies of only one or
two hundred. Only Bombus and the highly eusocial bees store food in quantity outside
of brood cells for use of adults and for transfer to larvae or brood cells as needed. In
most groups of social insects interactions between adults and young (i.e., brood-eggs,
larvae, pupae) are universal and important parts of the social organization. Exchange of
food between larvae and adults is well known in ants and vespid wasps, and it bas often
been supposed that Iarval activity or secretions are of great importance in maintaining
the social group. In most kinds of bees, however, there are no contacts between adults
and young ones because the cells in which the youngs are reared are closed before the
eggs hatch, each cell being mass provisioned with enough food to provide for the entire
growth of the larva. Progressive feeding, which of course involves adult-larva contact
from time to time during the growth of the larvae occurs among bees only in Apis, Bombus
and most allodapines. Even the highly eusocial meliponines have mass-provisioned cells
which, together with the cocoons spun by the mature larvae, completely enclose the
immature stages for the whole developmental period.
The number of species of solitary bees is greatest in the warmer, more arid sections
of the world, particularly in the semidesert areas as typified by those of
western North America, North America, South Africa, Australia, northwestern Argentina,
and South-central Eurasia. An abundant and diverse solitary bee fauna is common
adjacent to mountainous areas where moderate rainfall conditions exist. The rich bee
fauna found in mountains adjacent to arid or semiarid areas is only partially explained
by the stratification into altidudinal zones. The varied soil type and exposures, rock
niches, beetle holes in wood, and pithy-stemmed plants offer many diverse nesting niches.
The world-wide distribution of bees and the remarkable proliferation of species attests to
their high degree of adaptability. Numerous definitions have been proposed to distinguish between social and solitary bees, but recent information has shown that hard and
fast distinctions cannot always be nude.
The biology of behaviour of the solitary bees has attracted the attention of an increasing number of research workers during the past 15 years: those exploring the value
of solitary bees for pollination purposes (Bohart, 1972: Stephen, 1969) and those attempting to evaluate the significance of biological patterns as a supplementary tool for
the determination of phylogenetic relationships among bees (Michener. 1974). In the
Northwest about half of the Megachile rotundata larvae of the first generation pupate
and emerge as adults in the late summer. In some seasons a small percentage of the
progeny oftbe second generation emerge as a third generation, although they usually
have little time for nesting before being killed by cold temperatures. Appalalt., some
Megachile and Hylaeus and some Anthophora have more than one complete generatio!l
and overwinter as prepupae. Some single-generation species overwinter as adults in
their netal cells. For example, Osmia/ignaria usually emerges as an adult in April and
dies for about three weeks, The type of life cycle described above is apparently an
adaptation for early spring emergence, although some species exhibiting it (for example,
Osmia tera) do not until late spring. It is interesting to note that another species with
74
relatively late emergence. Osmia californica, usually has some individuals overwintering
as prepupae. Other bees overwintering as unemerged adults include most Osmia and
Andreno and some Antbophora, Megachile, and Emphoropsis. Bumble bees undergo a
life history similar to that of halictines. The overwintered female is sole egg layer for
several generations, which overlap broadly because egg laying is continuous. The
overwintermg female (queens) which are distintly larger than the earlier generations of
workers, are usually produced after the worker: brood ratio is favourable for intensive
feeding of queen brood. The Xylocopinae overwinter as emerged adults, as do halictines
and many apids. However, both sexes of Xylocopines overwinter in a dormant condition
and mate in the spring (some mating is reported to take place also in the fall). The
females usually overwinter in the natal nest with males from other nests often joining
them.
In many megachilids, males appear more numerous but the exact ratio v: Exact
causes leading to the variance are not well understood. In Megachile rotumdata , the
ratio of males to females in large samples taken from different nesting popula has been
seen to vary from I: I to 10: 1. The difference in ratios is directly correlated with the
diameter of the tunnel in which they are nesting. Emergence of males in advance of
females is evident in the alkali bee and in Megachile rotundata , as in most other species
of bees that have been studied. This phenomenon, referred to as protandry, is a general
rule among solitary bees and is interpreted a Evolutionary adaptation, assuring the presence of males for mating with emerging females.
The availability of suitable substrates for nesting is one of the most common factors
limiting the population and distribution of bee species. The principal type nesting microenvironments include soil, wood, small and large cavities and even fully exposed
surfaces. Species nesting in soil may select horizontal to gently sloping surfaces or
vertical banks. The vertical surface may be bare or overhung with vegetation, or rarely
with a grassy cover, and its exposure may provide maximum minimum shade. Vertical
banks are usually dry, but they may be moist in shaded gullies or dram ditches. The soil
surface may be wet or dry, but appreciable moist is usually available where and when
the cells are constructed. At least one observation has been made of Anthophora species tunneling in moderately hard sand-stol Ceratina, some Megachile. some Xylocopa
and several genera of small sphecid wasps burrow in the soft pithy plant stems of plants
such s raspberry, black-berry and sunflower in constructing nesting tunnels. A wide
variety of nesting material is utilized by megachilids. Their nests may be found in mail
shells (Old World Osmia), pockets or cracks in rocks (many osmiines), attached to
twigs or rock surfaces (some Dianthidirim ), or in narrow crevices ill almost any material
( Megachile rotundata ). Tendency of bees to renest in close proximity to their parent's
nest is one of the main causes of gregariousness, and that selection of a peculiar soil
condition has a minor effect. Most burrowing bees construct laterals from the main burrow with one or more cells arising from each lateral. Exceptions occur among species
that construct a main burrow with one or more cells attached to the end, along the
sides, or arranged within the main burrow in linear series. After the cells are provisioned
and capped, the nest, or a portion of it, is plugged. Some species only plug the area
immediately exterior of each cell, others completely backfill the laterals, and still other
plug the entrance when the nest is completed. Most species that arrange their cells in
75
line series construct complete cells, i.e. provide walls as well as top and bottom for
each cell (most Megachile, Anthidium ). In Megachile, the rounded base of each cell
inserted into the concave apex of the cell below, resulting in a nearly intact, weakly
differentiated column of cells.
The number of cells per nest ranges from one to several thousand. Most solitary soil
burrowing species make only one nest, which contains as many cells as foraging conditions and the reproductive potential of the bees allow. Nest of Nomia melanderi , may
contain from 5 to 24 cells, depending upon the availability offorage and th quality of the
substrate in which they are nesting. Some species of Osmia normally select small pockets in rocks that accommodate only one cell, but the same specie may place
several cells in somewhat larger holes. Megachile rotundata will accept tunnels which
accommodate only a single cell but more commonly uses long tubular cavities in which
it places as many as 20 cells. The reproductive potential of this species is even higher
(upto 40 eggs), but there seems to be an upper limit to the number of cells it places in
a single tube, independent of its length.
The world wide distribution of these bees and their remarkable ability for
proliferation are the result of their higher degree of adaptability. Floral fidelity is the
major attribute of these species making them sure of maintaining species characteristic
within plant species. Based upon degree of association in between bees and the plant
species i.e. the number of plant types visited for pollen collection (Linslay et al ., 1958),
the bees are termed monolactic (visiting one species) oligolactic (visiting few related
genera) or polylactic (visiting many types of plants). The solitary bee species arc mostly
oligolactic. Differences in seasonal adaptability, the pattern of origin vis-a-vis individual
bee specialization basically determine bees abundance for pollen collection on a particular plant. The principle factor which determines the effectiveness of such pollinators
for a particular crop or plant species depends upon the bee abundance, bee flight period,
bee flight hours per day and the number of flowers visited per day. The factors which
contribute to bee survival in Nature and their propagation depends upon the availability
of natural or man made nesting devices of preferred dimensions, abundance of natural
parasitic, or predators, incidence of disease or pesticide poisoning, and the natural
brood mortality during active or the dormant season. Most important is the synchronization of the bee flight period with the major blooming period of the crop. This is achieved
through appropriate provisions of nesting devices and regulating development of adults
so that there is synchrony in adults formation with crop blooming. Following are the
characteristic features of such bee management programmes for crop pollination.
i) Provision of appropriate nesting devices of brood cell formation.
(ii) Collection and safe storage of brood nest of cells at low temp.
iii) Checking/controlled emergence of parasites or removal diseased cells.
iv) Incubation of cells at appropriate temperature to regulate formation
Diversity of bees in India
Unlike other commonly known insects, excluding honey bees that belong to
genus Apis, bees have least attracted the attention of Indian taxonomists and biodiversity
workers. No doubt various aspects on honey bees ( Apis ) such as their domestication,
76
management and crop pollination have been considerably explored in India. However,
this is not true for non-Apis bees. Most of them forage on wild flowerings located in the
forests, buffer zones or more often that grow as weeds all along the cultivated crops.
The wild flowerings infact constitute the primary resource for nectar and pollen for most
of bees. Non- Apis solitary bees also visit cultivated crops in good populations but, as an
alternate to wild flowerings.
In North India, Batra (1977) recorded 89 species of solitary bees out of the 97 species studied. The occurrence of major bee genera in India shows that bees belonging to
family Megachilidae and Anthophoridae are most commonly distributed in India.since
India is a vast subcontinent with marked topographical and climatic differences, the
climatic and floristic conditions vary from tropical and subtropical to subtemperate and
temperate conditions.this is the reason that bee fauna from one region differs from the
other.most bees are distributed from valleys through plains to seashores. The Indian
species of Bombus is generally restricted to higher elevations especially in the
Himalayan ranges. Bingham (1897) recorded 24 species of Bumble bees from higher
elevations of Kashmir; Himachal through Sikkim and Assam. Mani (1962) reported four
species of bumble bees at elevations of over 4000 m at Himalaya. William (1991) has
recorded 28 species of bumble bees from Kashmir including areas under illegal control
of Pakistan. Xylocopa species and Pithitis smaragdula in the north western states of
India remained confined to 914 m (Kapil and Dhaliwal, 1968) and 391 m (Kapil and Kumar
1969) above the mean sea level. The other species are generally abundant in warmer,
semi-arid areas, yet distributed in temperate and mountain hill ranges also. The number
of species reported in each genera holds the following numerical order: Halictus 52,
Nomia 25, Bombus 28, Xylocopa 19, Megachile 44,and others are still less (Bingham,
1897; Batra ,1977).
Table 2.
Nesting behavior, nest acceptance and temperature tolerance of subtropical
Megachild and Xylocopinae bees (Source : Sihag 1991,1992)
Bee species
Crops
pollinated
Nesting Nest tunnel accepted
behavior
Diameter Length
(mm)
(cm)
Temp.
for
activity
0
C
Megachile haryanensis (M. nana )
Chalicodoma rubripes ( M. flavipes)
C.lanata (M. lanata )
Chalicodoma cephalotes
( M. cephalotes)
4.5-5.5
5.5-6.5
6.5-7.5
5.5-6.5
10-12
10-12
10-12
10-12
26-43
28-43
26-38
27-41
Xylocopa fenestrata
Xylocopa pubescens
X. valga
X. aestuans
10-12
10-12
10-12
10-12
23-30
23-30
23-30
23-30
25-48
25-48
5-30
10-47
Alfalfa
Leaf cutter bee
Alfalfa
Masson bee
Pigeon pea
Masson bee
Pigeon pea
Masson bee
Utilizes resin/
animal faecal
material for
partitioning and
closing the
cell/tunnels
Cucurbits
Carpenter bee
Cucurbits
Carpenter bee
Almonds,apples Carpenter bee
Cucurbits
Carpenter bee
77
Table 3. Important non - Apis bee pollinators of some agricultural crops in India
Crop/plant
Family
Bee species
Reference
Alfalfa ( Medicago sativa)
Leguminosae
Megachile bicolor , M. disjunta ,
M. flaviceps, M. femorata,
M. lanata, Nomia oxybeloides,
N.divisus, N.pusilla, Pithitis
smaragdula and Xylocopa
fenestrata,
Megachile nana, M. flaviceps
M. femorata , M. cephalotes
Braunsapis spp
M. lanata, M. cephalotes
M. cephalotes, Pithitis smaragdula
M. flaviceps, M. nana
Kapil et al. , 1974,
Abrol,1986a
Kapil et al. , 1975
Kapil and Jain,1980
Abrol,1985
Abrol,1986b
Berseem (Trifolium alexandrium)
M. flaviceps, M. nana
White clover (T. repens)
Bombus asiaticus , B. albopleuralis Abrol ,1987
Red clover (T. repens)
Bombus asiaticus, B. albopleuralis Abrol ,1987
Pigeon pea ( Cajanus cajan)
Megachile lanata, M. bicolor
M. flavipes, M. cephalotes
M. femorata, Megachile lanata,
Xylocopa fenestrata X. pubescens
M. bicolor, M. cephalotes
Chaudhary and
Jain 1978
Abrol,1985
Sunhemp ( Crotolaria juncea )
X. pubescens, X. fenestrate
Kapil and
Dhaliwal,1968
Grewal and
Singh, 1978
Abrol and
Kapil,1986
Abrol,1987a
Megachile lanata, M. fasciculata
X. fenestrate
Megachile lanata
M. bicolor
Pea ( Pisum sativum)
Sweet potato
( Ipomoea batatas)
Compositae
Convolvulaceae
X. fenestrata, X. pubescens
Megachile lanata
Braunsapis spp
X. fenestrata, X. pubescens
M. cephalotes, M. flavipes
B. albopleuralis, Bombus
asiaticu Lasioglossum spp.
X. fenestrata, B. albopleurali
Bombus asiaticus
Abrol,1986b
Kapil et al. , 1975
Kapil and Jain,1980
Abrol,1985
Abrol,1987
Abrol,1987
Egg plant ( Solanum melongena)
B. asiaticus
Abrol,1987
X. fenestrata , Ameigilla delicata
Batra,1967
A. subcosruleam, Nomia caliphora
Pithitis spp
Onion (Allium cepa )
Liliaceae
Nomioides spp
Lasioglossum spp, Nomioides spp
X. fenestrate
Kapil et al 1975
Abrol,1987
Field mustard
( Brassica campestris )
Cruciferae
Nomioides Megachilids
Andrenids Halictids
Andrena ilerda, A. leaena
Kapil et al 1971
78
Abrol,1986c
Rape ( Brassica napus )
Andrena ilerda
Halictids
Mohammad,1938
Rahman,1940
Raya ( Brassica juncea)
Andrena ilerda
A. leaena Andrena ilerda
Kapil et al. 1971
Abrol 1985,1986b
Taramira (Eruca sativa )
A. leaena Andrena ilerda
Colletes Halictus spp
Kapil et al. 1971
Cabbage and cauliflower
( B. oleracea )
Andrena ilerda , Lassioglossum spp Batra,1967
Pithitis smaragdula
Raddish ( Raphanus sativus)
Anthophora spp., Nomia spp.
Lassioglossum spp., Colletes spp.
Pumpkin and squashes
( Cucurbita spp.)
Cucurbitaceae
X. fenestrata, X. pubescens
Halictus spp., Nomioides spp.
Batra,1967
Atwal,1970
Smooth loofah
( Luffa aegyptica)
X. fenestrata, X. pubescens
P. smaragdula
Kapil et al. 1965-70
Cucumbers ( Cucumis melo)
Nomia spp., P. smaragdula
Nomioides variegata Halictids
Lasioglossum spp.
Kapil et al. 1965-70
Abrol & Bhat 1987
Cotton (Gossypium spp.)
Malvaceae
Lithurgens attratus
Batra 1977
Corriander
( Corraindrum sativum)
Umbelliferae
Nomioides spp.
Halictidae X. fenestrate
Abrol 1985
Saunf (Foeniculum vulagre )
Halictis spp., X. fenestrate
Abrol 1985
Carrot (Dacus carota )
Lasioglossum spp., Sphecoides
Hyleaus Nomioides Braunsapis
Pithitis smaragdula
Batra 1967
Ajowain
( Traechyspermum ammi )
Andrena spp. Nomioides
Halictus spp., Lasioglossum spp.
Batra 1967
Orange and lemon Citrus spp. Rutaceae
Lasioglossum spp., X. fenestrata
Batra 1977
Guava (Psidium guajava)
Myrtaceae
X. pubescens, X. fenestrata
Megachile lanata
Batra 1977
Mango ( Mangifera indica)
Anacardiaceae
Xylocopa spp., Megachile spp.,
Nomia spp., Lasioglossum spp.,
Batra, 1967
Pomegranate
( Punica granatum )
Punicaceae
Nomioides Lasioglossum
Halictus spp.
Batra, 1967
Apples (Pyrus malus )
Rosaceae
Colletes nursei Lasioglossum
Anon.1986
spp., Cattulum Osmia cornifrons
Andrena spp., Bombus haemorrhoidalis
Halictus vacchalli, Osmia spp.
Pithitis spp., X. fenestrata, Nomia spp.
Almond (P. amygdalus )
Lasioglossum spp., Xylocopa valga Abrol 1987
Cherry ( P. avium)
Xylocopa valga , Nomia spp.
Abrol 1987
Pear (P. cumminis)
Xylocopa valga , Nomia spp.
Abrol 1987
79
Table 4. Non-Apis pollinators of crops in India (Batra, 1977)
Crop
Pollinators
Brassica toria var. dichotoma and
B. campestris var. Sarson (Toria)
Andrena ilerda, Halictus sp., Andrena leaena ,
Andrena sp., Colletes spp., Anthophora sp.,
Brassica juncea (Raya)
Andrena ilerda, Andrena leaena
Eruca sativa (Taramira)
Anthophora vedetta, Colletes nursei,
Andrena ilerda
Brassica oleracea (cabbage and cauliflower)
Lasioglossum spp., Andrena ilerda,
Pithitis smargdula
Raphanus sativus (Raddish)
Nomioides variegata., N. divia, Colletes nursei,
Andrena leaena, Tetralonia pruinosa
Medicago sativa (Alfalfa)
Pithitis smargdula, Megachile flavipes,
Andrena levilabris
Trifolium alexandrium (Berseem)
Pithitis smargdula, Lasioglossum cattulum
Crotolaria juncea (Sunnhemp)
Xylocopa amethystine, Megachile anthracina,
M. lanata, M. fasciculate
Indigofera spp. (Indigo )
Nomia capitata (capitata)
Gossypium spp.(Cotton)
Anthophora confusa, Andrena ilerda
Luffa spp. (Ghiyatori)
Xylocopa spp., Tetralonia ovata,
Megachile coelioxyoides, Nomia eburneigera ,
N. curvipes, Lasioglossum cattulum,
Lasioglossum albescens
Momordica charantia (Butter gourd)
Nomioides spp., Pithitis smargdula,
Solanum melongena (Egg plant)
Xylocopa fenestrata, Amegilla delicata,
Nomia callichlora, N. oxybeloides,
Lassioglossum cattulum
Psidium guajava (Guava)
Xylocopa fenestrata, Megachile lanata
Citrus sinensis (orange)
Lassioglossum cattulum
Malus sylvestris (Apple)
Colletes nursei, Lassioglossum cattulum
Pollination in alfalfa
Alfalfa ( Medicogo sativa ) is a perennial herbaceous protein rich legume. It is one of
the most important fodder crop throughout the world. It is a cross plant and its flowers
being typically papilionaceous has staminal column held inside keel. Tripping i.e.
release of staminal column is considered to be a prerequisite, of cross pollination (Free.
1993). Most investigators have concluded that long tongued bees are not very important
in alfalfa seed production particularly in dry or arid conditions because of the fact that
the honey bee collect nectar from alfaalfa flowers from the side of the keel, thus avoid
the mechanical shock of the staminal column. Most of the workers has emphasized
importance of certain non- Apis species in the pollination of its flowers. Among a variety
of wild bees associated with alfalfa flowers, the investigations based in U.S.A. and
Alberta (Canada) showed that leaf cutter bee (Megachila rotundata) and a alkali bee
(Nomia mellandari could be exploited and propagated as alfalfa pollinator (Bohart, 1972).
80
A variety of non-Apis bees have been reported to be associated with some other crops in
this region (Kapil and Jain 1980). They reported megachilid species associated with
alfalfa under local conditions. The studies (Sihag, 1990) have suggested the inclusion
of some of these bees M. flavipas, M. femorata, M. lanata and M. cephalates under the
genus Chalcodoma. The major period of their activity for alfalfa pollination in the AprilMay months. Their broods however undergo dormancy as mature larvae first in the months
of June-July and then in winters. Until mid March, there are many overlapping generations in the months of September to November. High day temperature and dry condition
favour their foraging activity, brood formation viz-a-viz alfalfa pollination. 01 important
non- Apis alfalfa pollinators are Mellita leporilla. Atlthoph quadrifasciata and few other
species of Alldrella and Megachile .
The leaf cutter bee earlier called as Megachile pacifica, is a fast nest gregarious bee
and it nest in any such tunnel available in wood above the ground. It has been found to
accept the man made artificial nesting devices including tunneled wooden block, corrugated boards or the plastic tubes of appropriate tunnel size i diameter. Its native region
is South-West Asia and it spread to eastern USA around 1930. Today, i t i s
successfully managed for alfalfa pollination in many states of USA and southern parts of
Canada as well as many of the European countries. It is to, termed as million
dollars bee as it involve the inputs and outputs of millions of dollars in making various
mechanical devices and nesting materials and management techniques for alfalfa seed
production.
The alkali bee is another fast nesting gregarious bee. It however nest in big alkaline
soil. Once established favourable site may produce as many as 2 lakh cells per acre.
The best sites are bare or slightly vegetated tender silty loamy soils. Main adventage in
its management is that its nests can't be easily removed, stored or transported. There
have been many refinements in developing artificial nesting sites. The most important
step has been to keep the site puffy a little moist by providing plastic films several feet
below the surface. Heated calli are sometimes employed to enhance pupation and emergence of adults to coincide with alfalfa blooming. In addition to rains moulded soil, rats,
skunks, birds and variety of other parasites are its natural enemies. A temperature of
30°C is most appropriate for rapid pupation of the diapausing larvae.
Pithitus smaragdula , a green metallic bee is another important alfalfa pollinator. It is
a small carpenter bee and it makes nesting tunnels in cut pithy stems such as common
reeds ( Erianthus munja ).
Other crops
The wild bees are associated with many other crops also. The crops like clovers
(Ladino clover, red clover, egyptian clover, white clover and sweet clover), soybea
pigeon-pea sunhemp, broad bean, mustard, rape, coffee, papaya, cotton, sunflower
safflower and apples are few other important crops which could be benefited for
cross pollination. A variety of humble bees belonging to the genus Bombus utilized for
pollination of clovers. The bumble bees are semisocial bees as these initiate nesting as
81
an individual female, but later establish a large size colony. Osmia coerulescens , a leaf
cutter bee has also be reported to increase seed yields in red clover in USA Osmia
corniifrons has been successfully managed for apple pollination in northern and central
Japan. It nest in bamboo and hollow reed. The stingless bees commonly termed as
'melipona' bees are another important non- Apis group of true social bees which resembles
to Apis species as these form large colonies and yield sufficient honey for human
consumption. The indigenous people of tropical America and Africa have for centuries
managed various species of stingless bees for honey. Continuously changing climatic
conditions and over exploitations of forests and barren lands for agriculture have been
the major hurdles in natural propagation of wild bees. In north India alone there has been
about 73 per cent decline in their natural population during 1976-78 (Jain, 1993).
Looking upon their utility and importance and their implications in preserving flora, there
is a need to protect and conserve these bees for pollination.
Inspite of being represented in large numbers, non- Apis bee pollinators
have-received little attention. The probable reason seems their unpredictable seasonal
availability, lack of knowledge about their biology and host plant relationship. It was only
in the mid sixties that scientific interests were generated to study and understand their
life processes in India (Atwal, 1970). Failure of honeybees in the pollination of alfalfa
which requires tripping (Kapil et al. , 1977., Kapil and Jain 1979, 1980) dwindling of bee
colonies due to acute floral dearth in heavy monsoon during June to September and
similar effects during severe winter in Himalayan ranges from November to February and
prevalent bee diseases has created the necessity for exploration of alternate yet suitable non- Apis bee pollinators to augment crop yields in India. in addition to alfalfa,
clovers and fruits like apple,pear,peach,almond and several other crops such as sunflower, hybrid tomato,cotton,onion,carrot and cucurbits(Kapil and Dhaliwal,1968) can be
future potential crops requiring the services of the non-Apis pollinators.
Non- Apis bees and future prospects
Honey bees ( Genus Apis Linnaeus ) have often been credited with pollination services that are actually performed by other bee species. Hundreds of entomophilous crops
are now known that are very poorly pollinated by honey bees. The act in major is shared
by non-Apis or the so called wild bees (Parker et al. , 1987). There are few
estimates available for the value of non-Apis pollination. Estimations declared the value
of wild bee industry was well over US $ 1 million per year in terms of expenditures and
benefits in USA alone (Bohart, 1970, 1972). The benefits increased up to a range of US
$18-40 million in 1981 and, the total involvement of money over crossed US$ 81 billion
(Levin, 1983).
Recent technological advances in agronomic practices have focused primarily on
improving yield, increasing the number of crops grown and increasing the area of
harvestable crops. These advancements have been applied indiscriminately to the
majority of crops and, in a very short duration, they have transformed farms into
intensive monoculture systems. The positive results of these practices are impressive.
The quality and quantity of food has increased, food costs have decreased, numerous
82
fresh fruits and vegetables of high quality are available for much longer period, the
quality and types of prepared food products have greatly improved and, the large labour
force once required has been reduced, at the same time crop area have increased. On
the other hand, the technical advances and intensive farming practices have evolved
numerous negative impacts on crop pollination and non-Apis populations (Richards, 1993).
A number of conservation studies have concluded that clearing land of trees and
increased cultivation have inadvertently eliminated many of the nesting sites previously
used by non- Apis pollinators (Renner, 1996; Cane, 2001). Frequent applications of
broad-spectrum weedicides and pesticides have been responsible for the rapid decline
of pollinator numbers within agricultural areas (Batra, 1995c). Changing irrigation
practices have had long-term negative effects on soil nesting pollinators. Overgrazing of
rangeland and the use of herbicides have indirectly reduced the presence of pollinators
by decreasing diversity of pollen-nectar resources and, by eliminating required plant
resources that are utilized by various wild-non- Apis bees in nest construction (Batra,
1979b and 1979c). One of the consequences of an increased food supply for the world
has been inadvertently depopulating both numbers and species of native pollinators
within agricultural environment (Roubik, 2001). This situation must be addressed if our
agricultural ecosystem has to be sustained.
Second interesting aspect of pollination with honey bee for several crops lies in the
fact that after one or two morning forages honey bees are least interested in pollen
collection. It prefers collection of nectar only and pollens are attached to the scopal
bristles accidentally (Sharma and Gupta, 1993). In such events, honey bee enters and
after drinking nectar moves out of the corolla tube so swiftly that a flower hardly receives
any help in tripping. In the field, less than one percent of the self-tripped flowers produce
seed and most of the non-tripped flowers fail to do so. Studies available with regard to
many leguminous crops have reported several non-Apis bees as intentional trippers and
they continue to do so for many full days (Zaleski, 1956). They deposit pollens in their
nest chamber adjacent to their egg that hatch later as larva and feeds upon it. The
process usually requires at least 3-15 days as per nest size of the species. Apparently,
several wild-solitary bees are known for their effective pollination values abroad. Otherwise also, majority of non-Apis females are supported with dense brush of pollen
collecting scopa and in larger area of the body so that maximum amount of pollen load
may be collected in each trip to the field (Torchio, 1987).
The benefits we derive from native pollinators are believed to be increasing as the
honey bee industry experiences continued difficulties from mites and diseases. Furthermore the crops that are better pollinated by bees other than honey bees, are being
grown more intensively. To protect the native bee pollinators, two alternatives have been
suggested, one is the preservation and management of habitats and another is artificial
domestication and management of bee species (Stephen and Every, 1970; Williams et
al. , 1991). Bohart (1970, 1972) quoted that honey bees are not entirely satisfactory in
their use for the maximum output, in enclosures. On the contrary, non- Apis
species when invited to artificial nesting devices, have been found much more effective
83
pollinators. Apparently, a newer aspect has evolved which deals with "artificial
domestication and management of wild bees for crop pollination (ADMP)".
In North America 3,500 species of wild-solitary bees have been recorded, commonly
referred as "Pollen Bees" (Batra, 1994a). Alfalfa leafcutter bee ( Megachile rotundata ),
blue orchard bee ( Osmia lignaria propinqua ), fuzzy foot bees (Anthophora pilipes ) and,
mustached bees ( Anthophora abrupta) are some of the wild-bee cross
pollinators which are successfully used in the artificial domestication and management
programme, to enhance the crop pollination (Batra, 1982, 1991, 1993, 1994b). Robinson
et al, (1989b) detailed several parameters applicable for the pollinators. In brief, such
programmes intends to sustain a good population of pollinators close to the crops by
providing them artificial nesting devices and, the normal principle usually understood
was 'higher the number of pollinators higher will be seed yield'. Kapil, Grewal, Kumar
and Atwal (1970) recorded some of the insect pollinators and noted their comparative
abundance. However, after certain threshold limit population increase of the pollinator
does not put any further positive impact upon the seed yield (Strickler, 1997). Instead, a
consistency in increase in floral resource has to be maintained to sustain higher population of pollinator on the crop (Strickler, 1999; Strickler and Freitas, 1999), otherwise
fear concerning escape of bee species would persist.
A few other successful programmes exist that has enhanced the number of
native pollinators for fruit crops such as, using horn faced bees Osmia cornifrons in
Japan and use of Osmia cornuta in Europe (Maeta, 1978; Torchio and Asineo, 1985;
Maccagnani et al., 2003) and its introduction and establishment in USA (Batra, 1978a).
Identically, many species of Megachile, Heriades and Osmia are found in sufficient
numbers and need intensive investigations in this direction because they are quite
efficient visitors of several cultivated crops in northern India (p.o. author).
Certainly, ADMP has emerged as a new entomological industry (Bohart, 1970). In
India, the studies relevant to pollination of some more crops and the efficiency of several
bee species were recently commenced by Kumar et al ., (1994), Sharma and Gupta,
(2001) and, Kapil et al ., (2002). Some of these workers have made significant contribution by using the criteria such as amount of carried pollen loads, number of visits made
on flowers etc. for different bee species. Megachiline bees have the maximum area for
the collection of pollen grains (beneath their abdomens) hence usually top the list with
regard to carried pollen loads.
Author hereby suggest that several correlated aspects should be undertaken in future such as, bee foraging studies coinciding with rotation of crops; population studies
correlating different bee species on different crops; pollinator efficiency studies; effects
of insecticides on various pollinator bee species; study of immatures, their developmental periodicities and, its variation under controlled environment, so that supply of broods
as seeds may be implemented in practice, alongwith blooming of different crops; brood
transfer techniques; studies relating parasites-predators and pests of adults and broods
and, their mortality rate; impact of ecological factors on adults and broods; crop
yield studies; development of nesting devices for different bee species so as to retain
84
maximum population of bees on crops etc. These will ultimately help initiate artificial
domestication and management programme in the country for many useful bee species
to obtain better seed yields.
Suggested Readings
Abak K., Dasgan H.Y., Ikiz O., Uygun N., Sayalan M., Kaftanoglu O. and Yeninar H.
1997. Pollen production and quality of pepper grown in unheated greenhouses
during winter and the effects of bumble bees ( Bombus terrestris ) pollination on
fruit yield and quality Acta Hortic. 437: 303-307.
Abak K., Guler H.Y. 1994. pollen fertility and the vegetative growth of various eggplant
genotypes under low temperature greenhouse conditions. Acta Horticulturae
366 : 1994 85.
Abrol D.P. 1998. Mites associated with bumble bee, Bombus haemorrhoidalis Smith
(Hymenoptera : Apidae: Bombini). Indian Bee Journal 60 (3) :153-154.
Abrol, D. 1986a. Time and energy budgets of alfalfa pollinating bees Megachile nana and
Megachile flavipes Spinola (Hymenoptera, Megachilidae). Proceedings of the
Indian Academy of Sciences, Animal Science 95 (5) : 579-586.
Abrol, D. 1986b. Wing beat frequencies of Andrena ilerda and Andrena leaena
(Hymenoptera, Andrenidae). Annals of Biology (Ludhiana) 2 (1) : 98-99.
Abrol, D. 1988a. Ecology and behaviour of three bee species pollinating loquat (Eriobotrya
japonica Lindley). Proceeding of the Indian National Science Academy Part B.
Biological Science 54 (2/3): 161-164.
Abrol, D. 1988b. Effect of climatic factors on pollination activity of alfalfa-pollinating
subtropical bee Megachile nana Bingham and Megachile flavipes Spinola
(Hymenoptera : Megachilidae). Acta Oecol. Gen. 9 (4) : 371-378.
Abrol, D. 1988c. Foraging range of subtropical bees, Megachile flavipes , Megachile nana
(Hymenoptera : Megachilidae) and Apis florea (Hymenoptera : Apidae). J. Indian
Inst. Sci . 68 (1/2) : 43-48.
Abrol, D. 1989. Studies on ecology and behaviour of insect pollinators frequenting
strawberry blossoms and their impact on yield and fruit quality. Tropical Ecology
30 : 96-100.
Abrol, D. 1990. Energetics of nectar production in some apple cultivars as a predictor of
floral choice by honeybees. Tropical Ecology 31 : 116-122.
Abrol, D. 1992. Energetics of nectar production in some strawberry cultivars as a
predictor of floral choice by honey bees. Journal of Biosciences (Bangalore)
17 (1) : 41-44.
85
POLLINATION BIOLOGY OF SMALL CARDAMOM - A CASE STUDY
V. V. Belavadi
Department of Entomology, College of Agriculture.
University of Agricultural Sciences, Bangalore 560 065
Small Cardamom, Elettaria cardamomum , the Queen of Spices, is used in many
parts of the world, but most frequently in Indian and Scandanavian cuisine. Cardamom is
the world's second most expensive spice, second only to saffron. It is currently priced
between US $14,000 and $16,000 per ton. In recent years, cardamom production has
moved out of its native range in India to other regions of the world suitable for its production, including Sri Lanka, Guatemala, Indo-China and Tanzania. Guatemala is currently
the spice's major producer. Cardamom is, however, still a major crop in the Indian states
of Kerala, Karnataka and Tamil Nadu. It is the production of cardamom in these Indian
states that is focused on in this profile. In 2006-2007, 8545 MT of cardamom was produced from plantations covering 41,362 hectares in Kerala, with Karnataka following
with 1725 MT from 26,611 hectares and 965 MT from 5255 hectares of production in
Tamil Nadu (Spice Board of India estimates). In Kerala, Karnataka and Tamil Nadu, cardamom is grown between 600-1200 m above sea level in areas with annual rainfall levels
of 1500-4000 mm and temperatures ranging from 10-35ºC. Consistent rainfall between
February and April is essential for good flower production. Cardamom grows best on
soils with high organic content and good drainage. The crop is very sensitive to moisture
stress and excessive or insufficient light. Cardamom grows best in partial shade, with
50-60% filtered sunlight.
In recent years there has been increasing variability in rainfall levels during the
summer months, causing many farmers to resort to irrigating their crops, starting in
December. Indian cardamom is commonly grown in semi-cleared forest understory, in
artificially shaded plantations or in the understory of planted tree plantations. Plantations range in size from less than one to over 100 hectares, although most cardamom
plantations are small. Many small growers cultivate cardamom as a mixed crop with
areca nut and coffee. In most parts of the Hills of Karnataka (part of the Western Ghats),
where coffee is the major crop, coffee is grown on the slopes of the hills and cardamom
is cultivated in the cooler valleys. Canopy trees play an important role in maximizing
cardamom production. They provide the shade needed by cardamom plants and the
leaves that fall from them are used as mulch. In November and December, leaves fallen
from shade trees are clustered around the base of plants to prevent the soil from drying
during the summer dry season. Shade trees also provide nesting sites for pollinating
bees and floral resources for pollinators at times of the year when cardamom is not
blooming.
Elettaria cardamomum is a perennial species in the Zingiberaceae or ginger family.
It is native to the rainforests of the Western Ghats of southwest India, which share the
border among Kerala, Karnataka, and Tamil Nadu. Each plant generally grows to two or
three meters tall and is composed of a cluster of sheathed stems (pseudostems). Flow86
ers are borne on panicles emerging from the base of the plant (Fig.1). Each panicle can
produce up to 45 flowers. Three types of cardamom are cultivated in India - the Malabar
type with prostrated panicles, the Mysore type with erect panicles and the Vazukka
type with semi erect panicles. Cardamom plants flower continuously from the third week
of April, until the second week of November, with peak flowering between June and
August (Fig. 2). The bilaterally symmetrical white flowers (Fig. 3) have pink or purple
"nectar guides" on the labellum; these guides are thought to help pollinators find the
nectaries. The labellum, is a modified stamen that forms a landing platform for pollinators. Each flower has a solitary functional anther that releases pollen as the flower
opens. Each cardamom flower lasts a single day. Flowers open in the early morning
hours between 4 and 5 am and the anthers start to release pollen around 7:30 am.
Though all the pollen grains are not released at once, they have all been released (and
can be picked up by pollinators) by 10.30 am.
Insect pollinators are required for any valuable fruit production. Since the anther is
located very close to the labellum, a pollinator that has landed must squeeze through
below the anther to reach the nectar in the corolla tube. In the process, its head and
upper thorax come in contact with the stigma dislodging pollen onto the stigma. The
pollinator while retrieving its tongue and itself from the corolla tube, again rubs its thorax
and the upper part of its head on the anther, taking pollen grains. The ovary of any flower
will have anywhere between 18 to 27 ovules and for each ovule to become fertilized, the
flower requires as many pollen grains. A single flower receives as many as 130 visits
from pollinators on a sunny day to just over 20 visits on a rainy day (Belavadi et al .,
2000). If pollinated, each cardamom flower produces a single capsule containing about
21 seeds. If the flowers are bagged to prevent pollinators from visiting, none of the flowers set capsules. In comparison, there is 69% capsule set in sets of flowers that were
left open for pollinators. Cardamom is not self-incompatible; however, pollinator visits
are critical for effectively and efficiently moving pollen from the anthers to the stigma.
Thus, within the one day that a cardamom flower is open, it is essential that it is visited
by insect pollinators depositing an optimal quantity of pollen grains per flower (Fig. 4).
A recent study of cardamom's pollination ecology in the Western Ghats found a
diversity of bees, flies, butterflies and bird species visiting cardamom flowers. Few
visitors, however, were found to be true pollinators. Of the observed 18 flower visitor
species, only Apis cerana , A. dorsata , Amegilla spp. Trigona iridipennis and Ceratina
sp., actually collected pollen on their bodies (Sinu and Shivanna, 2007). All of these are
bees, and all evidence indicates that bees are the dominant pollinators of cardamom in
southwestern India, although the dominant bee visitors vary by plantation and region.
The bee diversity, bee density and per cent fruit set were found to vary between months
and was a function of the flower density (Figs. 5 & 6).
Several species of fast-flying long-tongued Amegilla bees also visit cardamom
flowers (Belavadi et. al., 2003, Parvathi & Ramachandra, 2005, Parvathi and Ramachandra
2006). Amegilla (Fig. 7) with its long tongue (~15mm) is capable of exhausting all the
nectar available in the corolla of cardamom flowers and may actually be the original
87
pollinators of wild cardamom. Amegilla is very active in the beginning and during the end
of the flowering season, when the flower density is low, and then is replaced by
the native honeybees in midseason when flower density is high. Despite the potential
importance of Amegilla evolutionarily and historically, currently A. cerana and A. dorsata
bees are the most important pollinators in the production of cultivated cardamom.
Despite the diversity of pollinating bee species found visiting cardamom in southwestern India, pollination is a concern for cardamom farmers. As cardamom requires
pollinators for fruit production it is crucial to ensure that large numbers of pollinators are
available during the blooming season. One of the major hurdles to ensuring cardamom
pollination is maintaining pollinator populations in plantations between years. Most
pollinators of cardamom are wild and thus move freely through the landscape. As
cardamom does not bloom year round, pollinators may leave cardamom plantations once
blooming finishes and they do not necessarily return the following season. A. cerana is
the only major cardamom pollinator that is kept in managed hives. Apis dorsata colonies
are highly migratory and move their nests in response to resources. The presence of a
single A. dorsata hive in a small plantation can provide for the majority of the necessary
pollination services. A. dorsata has never been successfully domesticated and is the
target of traditional honey collectors. The expense associated with farmed A. cerana
and the increasing rarity of A. dorsata has increased interest in maintaining a diversity
of wild bees in cardamom plantations for pollination services. An additional factor behind
the developing interest in wild bees is the presence in this region of a second crop that
is similarly reliant on bees for pollination : coffee.
Coffee has an even shorter blooming season, flowering for only a few days at a time
in March/April. Although not as reliant on bees for fruit production as cardamom, it is
known to need bees for maximized fruit production (Ricketts et al., 2004; Belavadi et al.,
2000). Conveniently, many of the same pollinators visit both cardamom and coffee
flowers, and coffee can tolerate the same levels of shade as cardamom requires. Often
farmers have holdings of both on their land. The innovative solution that is gaining
popularity for ensuring quality pollination services to cardamom and coffee in southwest
India is the use of managed forestry to create "sequential blooms" in mixed coffee and
cardamom plantations. Farmers of cardamom and coffee plantations often plant economically valuable timber trees or betel nut trees (a crop of domestic value) to provide
shade while maximizing the economic value of their plantations. As concern about declining pollination services has increased, however, a new approach to shade trees is
emerging. Instead of monocultures of timber trees, many farmers are now planting a
diversity of flowering tree species that in combination provide floral resources in plantations year round. This flower scheduling provides reliable pollen and nectar resources for
native bees at times of the year when neither cardamom nor coffee is blooming.
One well-documented example is the use of two species of Schefflera (S. venulosa
and S. wallachiana). Both of these tree species have flowers attractive to bees. Both
flower almost immediately after coffee finishes blooming in the region and just before
cardamom begins (Belavadi et al. , 2004), thus greatly reducing the number of bees that
88
Fig. 1 A cardamom Plantation
Fig. 3. Cardamom flower
Fig. 2. Flowering in cardamom
Fig. 4. Relation between number of visits/flower and
per cent capsule set
Fig. 5. Relation between number of flowers and number of bees visiting
Fig. 6. Per cent fruit set in cardamom in different months
Fig. 7. Amegilla sp.
leave plantations during the offseason. By providing year round floral resources, farmers
are ensuring that there will be enough bees around to pollinate cardamom and coffee
flowers during the appropriate seasons. Additional benefits in the use of diverse bloom
sequences, is that the trees provide nesting sites for many bee species; can be used to
support a third crop in mixed cropped plantations -most commonly black pepper and
some of the trees can also be selectively logged for timber production (Kuruvilla et al. ,
1995).
Suggested Readings
Belavadi, V. V. and Parvathi, C. 2000. Pollination in small cardamom ( Elettaria
cardamomum Maton). Journal of Palynology 35-36 : 141-153.
Belavadi, V. V., Parvathi, C., Raghunatha, R. and Ramachandra, Y. L. 2003. Bee
diversity in small cardamom plantations and their role in pollination. Paper
presented in "International Workshop on Conservation and Management of Bees
for Sustainable Development ", Bangalore, 13th to 18th October, 2003.
Belavadi, V. V., Chandrappa, Honnabyraiah, M. K. and Raju, B. 2004. Temporal variation
for nectar production in species of Schefflera ( Araliaceae ) - A strategy to avoid
competition for pollinators? Paper presented at the XXII International Congress
of Entomology, Brisbane, Australia 15 -21 August, 2004.
Kuruvilla, K. M., Radhakrishnan, V. V. and Madhusoodanan, K. J. 1995. Small
cardamom plantations - floristic calendar and bee pasturage trees. Journal of
Environmental Resources 3 : 32-33.
Parvathi, C. and Ramachandra, Y. L., 2006. Pollination biology of small cardamom
( Elettaria cardamomum L. Maton). Indian Bee J. 67.
Parvathi, C. and Ramachandra, Y. L. 2005. Relation between flower density in small
cardamom ( Elettaria cardamomum L. Maton) and pollinator species diversity.
Indian Bee J. 67.
Ricketts, T. 2004. Tropical forest fragments enhance pollinator activity in nearby coffee
crops. Conservation Biology 18 : 1262-1272.
S i n u , P. A . a n d S h i v a n n a , K . A . 2 0 0 7 . P o l l i n a t i o n e c o l o g y o f c a r d a m o m
( Eletteria cardamomum ) in the Western Ghats, India. Journal of Tropical
Ecology 23 : 493-496.
89
ROLE OF INSECT POLLINATORS IN PRODUCTION
OF OILSEED CROPS
S. P. Singh
Department of Entomology,
CCS Haryana Agricultural University, Hisar 125 004
Plant species are either self-pollinated or cross-pollinated. The flowers are so
constructed that either wind action or insects are needed to transfer pollen from anthers
to stigma for fertilization and consequently increasing the plant yield. The insect pollination increases not only the quantity but also the quality of the plant yield. The most
important pollinating insects of oilseed crops are solitary bees, bumblebees and honeybees. The insect pollinators play an important role in seed production of oilseed crops
mainly, rapeseed mustard, sunflower, castor, sesame and linseed.
RAPESEED-MUSTARD, Brassica spp.
The oilseed cruciferous crops are the plant species from the Genus Brassica
(Family: Cruciferae) and include different oilseed crops like winter rape ( Brassica napus),
toria ( B. campestris), Ethiopian mustard ( B. carinata ), Indian mustard ( B. juncea ), wild
mustard ( B. nigra ) and taramira ( Eruca sativa ). All these crops are called rapeseedmustard and are traditionally grown as major group of winter oilseed crops. Most of the
Brassica species are self-incompatible to some extent but this varies with the species
and cultivars concerned and even with the age of the plant.
Honeybees visit rape flowers for collection of both pollen and nectar which, in turn,
results into florets get cross pollinated. A plant visited by honeybees possessed 40
seeds per head, when compared to plants without bee pollination which had only 15
seeds per head. Besides honeybees, other pollinators such as flies, butterflies and
wasps are also observed help in open pollination. However, frequency of their visit is very
less. The number of flowers visited by honeybees per minute was more in open pollination compared to other pollinators. Kulkarni and Dhanorkar (1998) reported honeybees
as main pollinating agents, followed by solitary, alkali and carpenter bees. Among honey
bees, Apis dorsata , was prominent and constituted 74.36 per cent, followed by A. cerana
indica (18.73 per cent) and A. florea (6.73 per cent). Among 13 species of pollinators, A.
dorsata was most prominent constituting 45.88 per cent, followed by A. florea (27.35
per cent), A. mellifera (10.81 per cent), A. cerana indica (4.17 per cent) and other
pollinators (2.45 per cent) (Guruprasad, 2001).
A total of 14 species of pollinators were found foraging on rape flower heads. Of
these, four species belonged to Hymenoptera comprising more than 84.27 per cent of
total pollinators, eight species to Lepidoptera and two species to Diptera. Among the
different pollinators, the most common and dominant bee noticed on rape flower was
Apis dorsata (37.23 per cent), followed by A. florea (28.74 per cent) and A. cerana
indica (18.32 per cent) and other pollinators (15.71 per cent). A. dorsata visitation was
noticed from 0800 to 1600 hr with peak activity at 1600 hr (45.56 bees/m2/5 min). Bee
90
activity declined in the afternoon reaching lowest at 1800 hr (18.96 bees/m2/5min). A.
florea visitation was noticed from 0800 to 1800 hr with peak activity at 1400 and 1600 hr
which recorded 34.80 and 36.93 bees/m2/5min, respectively. Bee activity decreased in
the afternoon. A. cerana indica activity increased in the afternoon from 1200 to 1600 hr
which ranged between 20.53 to 23.52 bees/m2/5 min. Activity of other pollinators was
maximum at 1000 and 1600 hr which recorded 18.53 and 17.85 other pollinators/m2/5
min, respectively. Per cent pod setting, seeds per pod and proportion of healthy seeds
of rapeseed were significantly higher in open-pollinated flowers than in net-caged and
muslin-bagged ones. The average weight of 100 seeds and oil content of seeds
were significantly greater from muslin-bagged than from net-caged and open-pollinated
flowers. Oil yield was 9.76 and 1.55 times higher under open pollination and net caging,
respectively, than under muslin bagging. (Mishra et al .,1988).
Tewari and Singh (1983) demonstrated a 11decrease in seed set and yield with increasing distance from three A. cerana colonies. Mishra et al. , (1988) caged sarson
plants in either muslin cages, nylon net cages or left them exposed; 59, 70 and 95% of
their flowers set pods containing 3.5, 0.5 and 12.7 seeds per pod, respectively. Similarly, Rauala (1972) reported that plants in cages with honeybees gave 68% set, 9%
sets per pod and 627 seeds per 100 flowers compared with 9% set, 2.3 seeds per pod
and 28 seeds per 100 flowers in cages without honeybees. Varma and Joshi (1983)
found that the percentage flower set and number of seeds per pod was 19% and 2.3 for
bagged flowers, 45% and 4.0 for plants in wire netting cages that prevented access to
large insects, and 93% and 6.4 for exposed plants.
Recently, studies conducted at Hisar during 2006-07 revealed the highest mustard
yield in open pollination set, followed by hive inside out. In open pollination conditions,
the yield increased by 30.3 per cent, followed by one honeybee hive half inside by 18.2
per cent over to without honeybees' conditions (Table 1).
Table 1.
Role of honeybees in enhancement of yields in mustard at Hisar, 2006-07
Treatments
No. of pods/plant
Yield (kg/ha)
% Increase in
yield over T1
90.5
1650
---
T2-With bees (One bee hive full inside)
120.5
1720
4.2
T3-With bees (One bee-hive half inside out)
152.5
1950
18.2
T4-Open pollination
165.0
2150
30.3
T1-Without bees (Enclosed)
SUNFOWER, Heliantus annus L.
The honeybees are the main pollinating agents of the sunflowers in almost anywhere
they are planted. Other bees such as bumble bees and wild bees also visit the sunflowers. Nevertheless, it was with the honeybees that most growth or increased yield of
sunflower seeds has been attained. Bee pollination is critical for production of sunflower
seeds, while the honeybees are often used effectively to pollinate sunflowers (at 2 to 2.5
hives per acre).
91
In the Indian sub-continent the honeybees Apis dorsata and A. florea are common
visitors to sunflowers and are joined by Apis cerana foragers. Other Hymenoptera
visitors include species of Andrena, Anthophora, Ceratina, Halictus, Megachile, Scolia,
Trigona and Xylocopa . Many species of Diptera ( syrphids, Phytomia argyrocephela and
Eristalinus arvorum) also readily visit the sunflower (Vaish et al. , 1978). Panchabhavi
and Rao (1978) inter-planted a sunflower plot with rows of niger, and found that the
sunflowers attracted seven times as many syrphids and six times as many A. flora and
had twice the seed set as sunflowers in a pure stand at one km distance. The insect
pollinators visiting sunflower crop in Haryana are listed in (Table 2).
Observations and experiments on field scale confirmed the value of bees in
pollinating sunflowers and demonstrated that a shortage of bees may limit sunflower
seed production. The ability to produce hybrid sunflower seed using cytoplasmic male
sterile lines depends upon high populations of pollinators which are needed to transfer
pollen from the pollen-bearing restorer lines to the male sterile female parents.
Satyanarayana and Seetharam (1982) found that in a hybrid seed crop, planted with one
male fertile to blocks of five male sterile rows, the numbers of Apis cerana and A. dorsata
foragers were greatest on the male fertile row, and decreased toward the central rows of
the male sterile blocks. This was reflected in a lower seed set of the central rows, and
they obtained greater seed yields from plots planted with a 1 : 3 and 1 : 4 ratio of male
fertile: male sterile rows than from a 1 : 5 ratio.
The bagged heads usually set about 10-20% seed compared with 70-90% in
exposed heads, so it seemed likely that considerable self-pollination could occur. In
sunflower, filled seeds/head, total seed weight/head, and 1000-seed weight were more
in case of open pollinated crop, followed by hand and self pollinated crops, whereas
empty seeds/head were more in case of self pollinated, followed by hand and open
pollinated crop. About 27 per cent yield was increased, when honeybees were put in the
sunflower plot. Oil content of sunflower seeds under different mode of pollinations varied
between 22.15 to 36.30 per cent. The highest oil content was obtained from the crop
under hand+insect pollination. Higher oil content was obtained (28.13 per cent) when
the crop was caged with A. cerana indica over hand pollinated crop (26.90 per cent). The
lowest oil content (22.15 per cent) was obtained in control (Kumar et al. , 2002).
Honeybees were in adequate numbers in sunflower fields close to bush, but they
were much fewer in fields 3.2 km from bush, and pollination decreased with increasing
distance from the bush. In the USSR, sunflower crops with apiaries within 100 m had 1629% greater yields than when no honeybee colonies were present. In India, a 20-ha field
with 67 Apis cerana colonies had 72% seed set, compared to 57 and 55% for two fields
with no colonies (Panchabhavi et al. , 1976).
It is reported that as the average number of bees per hectare increased from 819 to
1827, the seed yield increased from 710 to 1140 kg/ ha. Langridge and Goodman (1981)
suggested 1.0- 2.4 bees per head are needed for adequate pollination. Further, it has
been confirmed that as the distance between the crop and apiary increases, the
concentration of honeybee foragers and seed yield decreases.
92
Table 2.
Insect flower visitors of sunflower Helianthus annus at Hisar
Order
Family
Scientific name
Hymenoptera
Apidae
Apis dorsata Fab.
Apidae
Apis mellifera
Apidae
Linn. Apis florea
Megachilidae
Fab.
Megachilidae
Megachile sp.
Megachilidae
Megachile sp.
Megachilidae
Megachile sp.
Megachilidae
Megachile sp.
Megachilidae
Megachile sp.
Halictidae
Megachile sp.
Halictidae
Nomia sp.
Halictidae
Nomia sp.
Apidae
Trigona sp.
Anthophoridae
Ceratina sexmaculata Smith.
Xylocopidae
Xylocopa amethystina Fabr.
Xylocopa leucothorax (De Gear)
Polistes hebraeus Fabr.
Vespidae
Odynerus ovalis Sauss
Diptera
Scoliidae
Elis thoracica
Anthophoridae
Anthophora zonota (Linn.)
Sphecidae
Stizus sp.
Mutillidae
Mutilla sexmaculata
Formicidae
Monomorium indicum Forel.
Halictidae
Halictus sp.
Calliphoridae
Chrysomyia bezziana (Villeneuve)
Syrphidae
Episyrphus balteatus (De Geer)
Syrphidae
Eristalis tenax Linn.
Syrphidae
Eristalis sp.
Syrphidae
Eristalis sp.
Syrphidae
Eristalis sp.
Syrphidae
Eristalis sp.
(Arya et al. , 1994; Kamal, 2002).
CASTOR, Ricinus communis L.
The greenish-yellow flower of castor has three to five united sepals and no petals.
The male flower has numerous branched stamens, arid the female flower has a superior
three-celled ovary terminated by three styles. Both sexes occur in the same panicle;
93
the female flowers in the upper part have mostly set before the male flowers in the lower
part have opened. The pollination requirements and the pollinating agents are unknown.
Though castor is mostly wind pollinated, insects may play some part, as extra-floral
glands on leaves below the flowers produce much nectar. The honeybees visit staminate
flowers of castor and obtain large amounts of pollen. However, tests showed that they
are of no value as pollinators.
SESAME, Sesamum indicum L.
In India, many flowers have aborted anthers and do not shed pollen so visits by
insects are necessary for cross-pollination to occur (Phadke et al .,1967). Plants
exposed to insect visits had a 25% greater yield than plants from which insects were
excluded (Deodikar and Suryanarayana, 1977). In Egypt, Rashad et al. , (1979) found
that plots of sesame caged with honeybees ( Apis mellifera ), plots caged without bees,
and plots not caged had means of 60,46, and 71 seeds per pod, 71,25 and 69 pods per
plant and 195, 120 and 196 g of seed per plant, respectively. In India, Panda et al. ,
(1988) reported that plots caged with A. cerana yielded a mean of 2.6 kg seed compared
with 1.6 kg from plots caged without bees and 2.4 kg from plots not caged.
On sesame, honeybees are the most abundant insects comprising 32% of the
foraging population, and that species of Megachile, Polistes and Eristalis were also
important. A. cerana (the most abundant) and A. florea visited all the cultivars (Rao et
al. , 1981) in India, and both species of bee preferred the same cultivar. A. dorsata failed
to visit one of the cultivars and was much less numerous than the other two species. A.
cerana began foraging for nectar and for pollen at about 06.00 h. Pollen collection ceased
by 11.00 h; nectar collection continued, thereafter but by a smaller population. A. dorsata
and A. florea began foraging at about 07.00 hand 08.00 h, respectively. Rao et al. ,
(1981) further recorded that individual A. dorsata , A. cerana and A. florea visited 5.0, 6.3
and 1.9 flowers per minute and visited 4.2, 5.1 and 1.6 plants, respectively, during
observation. Flowers that had been pollinated by A. dorsata, A. cerana and A. florea
gave means of 53, 51 and 45 seeds per pod, and mean weights of 0 .15,0.14 and 0.12 g
per seed, respectively.
LINSEED, Linum usitatissimum L.
Nectar glands located at the base of the filaments are visited by many insects including Bombus spp., various Diptera and butterflies, but honeybees are the most abundant. Opinion differs as to whether insect visits increase seed production or not. The
effects of honeybee pollination have been reported with increase in: the number of seeds
from 18 to 26%; the number of seeds per capsule from 1 to 45%, the weight of seeds
harvested from 0 to 49%; and the weight of 1000 seeds by 11%. Similar yield results
obtained from plots caged without bees, plots caged with bees and plots not caged as
938, 954 and 947 kg/ha, respectively. Williams (1991) found that in a greenhouse, supplementary hand pollination slightly increased the percentage flower set (from 60 to 73%)
and gave more seeds per capsule (from 5.68 to 6.85), but the naturally auto-pollinated
controls set more capsules per plant (207: 187) and the seeds were heavier (7.63: 6.29
94
g per 1000 seeds). In the field plots caged with and without honeybees did not differ
in any aspect of yield which the indicated that movement of the plants by wind was
sufficient to ensure that maximum auto-pollination occurred.
These contradictory results on the value of insect pollination might be explained
by differences in the cultivars concerned in self-compatibility, in the relative heights of
stamens and stigmas and in the ability and ease of auto-pollination.
Suggested Readings
Ahmed, B. and Rehman, A., 2002, Population dynamics of insect foragers and their
effect on seed yield of rapeseed ( Brassica campestris L. var. toria). Indian Bee
J . 64 (3 & 4) : 1-5.
Atwal, A.S. 1970. Insect pollinators of crops (Biology, ecology and utilization of insects
other than honeybees in the pollination of crops- Final Research Report) (196870) Ludhiana. PAU, 116 pp.
Kumar, K. 2002. Studies on insect pollinators of sunflower (Helianthus annuus L.).
M.Sc. Thesis, CCSHAU, Hisar. 62 p.
Priti and Sihag, R. C. 1997. Diversity, visitation frequency, foraging behaviour and pollinating efficiency of insect pollinators visiting cauliflower ( Brassica oleracea L.
var. botrytis cv. Hazipur Local) blossoms. Indian Bee J. 59 (4) : 230-237.
Singh, J., Mishra, R. C. and Agarwal, O. P, 2002. Pollinating efficiency of Apis species
in hybrid seed production of Brassica napus .L. Indian Bee J., 64 (3 & 4) : 62-63.
Turnock, W. J., Kevan, P. G., Laverty, T. M. and Dumouchel, L. 2006. Abundance and
species of bumble bees (Hymenoptera: Apoidea : Bombinae) in fields of canola,
Brassica rapa, in Manitoba: an 8-year record. Journal of the Entomological
Society of Ontario , 137 : 31-40.
Viraktmath, S. A. and Patil, R. K., 2002. Effect of bee pollination and change in crop
environment on seed yield of sunflower: Indian Bee J. , 64 (1 & 2) : 35-42.
Viraktmath, S. A., Patil, B., Murasing, S. and Guruprasad, G. S., 2001. Relative
abundance of pollinator fauna of cross-pollinated oilseed crops at Dharwad in
Karnataka (India). Indian Bee J. , 63 (3 & 4) : 64-67.
95
ROLE OF INSECT POLLINATORS IN PRODUCTION
OF TEMPERATE FRUITS
J. K. Gupta
Department of Entomology and Apiculture,
Dr. YS Parmar University of Horticulture and Forestry, Nauni, Solan (HP), India
Pollinators play an important role in increasing productivity of temperate fruit. For
fruit and seed setting, pollination can be self pollination or cross pollination. In self
pollination, pollen from the same flower can fertilize its stigma. In cross pollination,
pollen has to be transferred from anthers of one flower to the stigma of another flower
and in this process some agent is required for this transfer. In highly cross pollinated
crop like apple, most of the commercial cultivars are cross pollinated and for proper fruit
setting, pollen has to come from flowers of another cultivar which is also known as
pollinizer.
Insect pollinators
In cross pollination, different types of insect pollinators are playing important role.
All the flower visiting insects are not effective pollinator. Some level of pollination is
accomplished by all the flower visitors but efficient pollinators have some qualities which are:
1. They show floral constancy resulting in effective pollen transfer from male to female
parts of different flowers of the target crop.
2. They have hairiness on their bodies which helps them to carry more pollen grains
from the flowers they visit and then deposit these grains on stigma of another flower.
3. They should have large population and long working hours.
4. It should be easy to domesticate them and use for pollination whenever required.
Honey bees have all these qualities and are, therefore, used successfully for
effective pollination. They visit the flowers for collecting nectar and pollen and in this
process accomplish the pollination successfully.
As an example of highly cross pollinated temperate fruit crop, different aspects of
apple pollination are given below :
Different varieties of pollinizer
Examples : Crab apple, Golden delicious, Tydeman, Red gold, Gala, Red fuji etc.
In apple orchards, it is essential to have trees of pollinizer variety planted among the
commercial cultivar. The contribution of pollinators under such condition increases even
more as pollen has to be transferred from flowers on tree of a pollinizer to the stigma of
flowers of commercial cultivar on another tree.
96
Planting of pollinizer trees in an apple orchard
An orchardist has to keep in mind that it is essential to plant pollinizers among the
commercial cultivar while doing plantations in new orchard. On scientific lines, different
planting methods have been suggested which provide 11, 15, 20 or 33 per cent pollinizer
in the orchard. For economic fruit set, it is recommended to have 33 per cent pollinizer
trees among the commercial cultivar. However, it has been often found that in most of
the orchards, pollinizer level is very low since the orchardists get higher income from the
fruit of commercial cultivar.
How to manage orchards having less pollinizer?
Orchards having low level of pollinizer can be compensated by grafting cuttings of
pollinizer on the branches of trees of commercial cultivar (Fig. 1). Another method is to
hang bunches of flowers of pollinizer on the blooming trees of commercial cultivar (Fig.
2). Pollen dispenser can also be used for proper pollination which has been successfully
tested by our university (Fig. 3).
Bloom of pollinizer which is planted among the commercial cultivars should overlap
sufficiently with the commercial cultivar, which sometimes does not happen. It is, therefore, recommended that instead of depending on a single pollinizer cultivar, there should
be a mixture of pollinizer cultivars among the commercial cultivars.
Now it has become essential to use bee colonies for pollination, why so?
In Himachal Pradesh, apple is being commercially grown for so many decades but
for the last 15-20 years, need for using bee colonies for apple pollination has been
realized. Main reason for this necessity is the decline in population of natural pollinators. Pollinator population has declined due to following reasons:
Indiscriminate use of pesticides resulting in loss of pollinating insects
Deforestation and cleaning of land for intensive agriculture due to which nesting
sites of natural pollinators have been destroyed
Monoculture has also resulted in non availability of floral sources to the pollinators
for most parts of the year.
Due to above mentioned reasons there has been decline in the population of naturally occurring pollinators. Today it is not possible to have good apple crop without the
provision of bee colonies for pollination. Now the orchardist of Himachal Pradesh has
also realized that as he needs fertilizers and different types of sprays for raising healthy
crop, so are the bees required for getting good apple crop.
Number of honey bee colonies required for pollination
The number of colonies required for pollination depends on the area of the orchard
and population of natural pollinators. Apple orchards having required level of pollinizer
(33 per cent) need 2-3 bee colonies per hectare for pollination. The bee colonies should
be placed in the centre of orchard so that honey bees pollinate the crop in all directions.
97
Orchards having low level of pollinizer require as many as 8 colonies per hectare. These
colonies should be kept in two groups (4 colonies/group, Fig. 1). Keep a distance of 50
metres among these two groups of bee colonies. In this manner, honey bees get distributed in all directions in the orchard and help in better pollination. In pollinizer deficient
orchards, pollinizer can be grafted on main commercial trees (Fig. 2) or floral bunches of
pollinizer can be hanged on commercial apple trees(Figs. 3-4) even pollen insert (Fig.
5) can be used.
Condition of bee colonies to be used for pollination
The bee colonies to be used for pollination should be strong (at least of 6-8 frame
strength) and should have good queens. These colonies should be brood right and have
brood on 3-4 frames because brood increases food requirements of a colony which results in more foragers going to collect their food which helps in accomplishing the pollination of the flowers they visit. Therefore, before hiring colonies for pollination, remove
the top cover and check on how many frames the bees are? It should be checked that
there are frames covered by the bees and not mere the empty frames among 8-10 frames.
Placement of bee colonies in the orchard
Honey bee colonies should be shifted to orchards only when the flowering has started
(5%) in the apple trees. Do not shift the bee colonies before start of apple bloom otherwise bees will get oriented on other available flora and may visit the apple bloom in less
number when its flowering starts. Proper pollination not only increases the productivity
but also affects quality of the produce such as shape and size of the fruit.
Many times it is seen that the orchardists shift the colonies in their orchard from one
place to the other thinking that it would accomplish proper pollination in all parts of the
orchard. But this is incorrect method and by such short distance shifting, many foraging
bees are lost resulting in decline of their number which adversely affects the pollination.
Therefore, it is important to select proper site before placing the bee colonies for pollination.
Protecting bee colonies from harmful effects of insecticides
Many times the orchardists spray insecticides on the blooming apple crop which
is harmful to all types of pollinating insects. Under such conditions the benefits of
pesticide application are less and losses are more. Therefore, it is better not to spray
insecticides on the blooming crop. But if it is required urgently to control the pests,
these should be applied only in the evening or early morning when pollinators are not
visiting the bloom. The colonies kept in the orchards should be covered with burlap cloth
before the spraying.
Getting bee colonies for pollination
In India, it is only in Himachal Pradesh that the orchardists hire bee colonies for
pollination of apple crop on rental charges of Rs 450-600 per colony. The bee colonies
are returned after pollination of the crop. But generally the required number of colonies
is not available for pollination.
98
Fig. 1. G r o u p o f f o u r h o n e y b e e c o l o n i e s k e p t f o r
pollination of apple crop
Fig. 2. Grafted pollinizer on
commercial cultivar of
apple
Fig. 4. Bunch of floral twigs of pollinizer hanging on the
commercial apple cultivar to facilitate pollination
Fig. 3. An orchardist transporting blooming twigs of
pollinizer for pollinating
his pollinizer deficient
commercial crop of
apple.
Fig. 5. Pollen insert fixed at the hive entrance
Fig. 6. F o r a g i n g
rate
(number of flowers
visited/minute) of
hive bees on flowers of different
temperate fruits
Fig. 7. Number of loose
pollen grains on
bodies of hive
bees from on flowers of different
temperate fruits
Fig. 8. P o l l i n a t i o n i n d i ces of the hive
bees on different
temperate fruits
Rating of pollinator efficiency
Several workers considered abundance alone. But in addition to abundance, other
characteristics are also important which include :
o
body size
o
foraging behaviour
o
loose pollen grain carrying capacity
o
preference for alternate plant species
On the basis of foraging rate, loose pollen grains and abundance of pollinators,
pollination indices of different pollinators can be determined to know pollination
efficiency. Pollination indices would differ even for same pollinator on different crops. As
an example, pollination indices calculated for the hive bees on different stone and pome
fruit will depict the same (Figs. 6-8).
Increases in crop yields due to cross pollination
Increases in yield over self pollination (per cent): some examples
o
Apple
180-6950
o
Pear
240-6014
o
Plum
6.7-2739
o
Cherry
56.1-1000
o
Strawberry
17.4-91.9
Strawberry flower needs 16-25 bee visits to bear perfect fruit. With 16-20 visits/
flower, berry weight has been found to be 5.36 g whereas with 21-25 visits, berry weight
increased to 8.13 g.
Strawberry flowers visited by both wild bees and honey bees have been reported to
be completely developed in contrast to those visited by only honey bees or only wild
bees which shows the importance of diversity of pollinators. Such effects have been
rarely studied but may be widespread.
In addition to honey bees, there are more than 2 0000 other bee species which are
acting as effective pollinator of large number of plant species. These bees have now
been grouped under "pollen bees". The pollen bees include solitary bees like Megachile,
Nomia, Osmia, Halictus, Andrena, Ceratina , etc. which arealso important pollinators of
fruit crops. These bees have also been reared by providing artificial nesting sites and
managed for pollination of different crops in different parts of the world. But the usefulness of these bees is limited because their population fluctuates greatly from year to
year. Dipteran flies also constitute another important group of pollinators. But the flies
are not as busy pollinator as the bees because they take food for their own consumption
only in contrast to the bees which nurse their brood and have more food requirements.
However, flies play an important role under certain climatic conditions when the bees do
not visit the flowers. The flies require suitable breeding grounds which are wet, having
99
decaying vegetable material near the crop to be pollinated as they do not travel far.
Drone flies ( Eristalis sp.) and other syrphids are well known pollinators temperate fruit
crops.
Strategies for conservation of natural pollinators :
For conservation of natural pollinators and to increase their population some
possible management practices are :
o
Development of habitat management programmes to increase number of native pollinators
o
Adopting proper pest management strategy based on sound ecological principles
o
Need based application of right pesticide at right time and at recommended dose
o
Selection of pesticide that is least inimical to bioenvironment, e.g. summer spray oil to
check population build up of phytophagous mites
o
Encouraging agro and social forestry plantations
o
Taking up plantation on waste land
o
Educating farmers by arranging farmer field school after assessing their basic knowledge
o
Preparing requisite literature pertaining to different activities
o
Training in handling of honey bees and using honey bees for managed pollination in an
economic way
o
Diversification on bee forage front essential due to excessive monoculture through
plantation of multipurpose flora
o
Provision of artificial nesting sites for the potential pollinators after identifying the sites
o
Identify good agricultural practices which promote pollination services
o
Capacity building of different stake holders spanning from researcher to farmers
o
Compensating farmers who apply management strategies to conserve biodiversity through
funding from different agro-environmental schemes as is being practised in Europe and
United States.
Selected Readings
Klein, A. M., Vaissiere, B. E., Cane, J. H.,Steffan-Dewenter, I., Cunningham, S. A.,
Kremen, C. and Tscharntke, T. 2007. Importance of pollinators in changing
landscapes for world crops. Proc. R. Soc . B . 274 : 303-313.
Torchio, P. F. 1990. Diversification of pollination strategies for U.S. crops. Environmental Entomology . 19 : 1649-1656.
Gupta, J. K. and Gupta, P. R. 1997. Diversification of pollinators. In : Fruit Crops
Pollination (eds. L. R. Verma and K. K. Jindal), Kalayani Publishers, Ludhiana,
pp 29-47.
100
IMPACT OF INSECT POLLINATORS ON
TEMPERATE VEGETABLE SEED CROPS
Harish Kumar Sharma
Department of Entomology and Apiculture,
Dr Y S Parmar University of Horticulture and Forestry,
Nauni, Solan 173 230, Himachal Pradesh
Insect pollination is crucial in the production of many commercially important crops.
Enhancing the amount or quality of insect pollination can lead to increase in crop value
by decreasing the time to crop maturity and also by increasing its uniformity, quantity
and quality. The insects comprise diverse group and play a role in crop pollination range
from those that are incidental flower visitors to those that are adapted for pollinating
flowers.
Honey bees are the main pollinators in cross- pollinated vegetable crops such as
Cruciferous, Umbelliferous, Liliaceous, Amaryllidaceous and Cucurbitaceous vegetables
etc. In both developed and developing countries, the pollination services of honey bees
are used to increase the productivity of various agricultural and horticultural crops.
The information on the role of honey bees in pollination, which leads to increase in
the quality and yield of crops has been widely documented. Studies have shown that bee
pollination increases fruit and seed production. High increases in yield are expected in
those crops which are self- sterile and produce fruits and seeds only, if cross- pollinated.
Insect pollinators
Insect visitors on the bloom of different crops depend upon the geographical distribution, climatic condition, availability of natural sites for nesting and hibernation and the
relationship between plants and insect species. Pollination diversity recorded on the
bloom of different important vegetable crops is discussed below:
Brassica oleracea L. (Cabbage, Cauliflower, Brussels Sprout)
Cultivated species of Brassica are very attractive to insects especially honeybees.
Flies (Syrphidae, Calliphorinae, Muscidae) and small beetles are occasional visitors.
Free and Williams (1973) recorded Osmina rufa , bumblebees and many dipteran species visiting Brussels Sprout flowers. They found all the wild bees and many syrphidae
carrying pollen almost equal to honeybees. However, honeybees are the most important
pollinators of B. oleracea comprising 98 per cent of visitors in Egypt (Hussein and
Abden-Aal, 1982) and 99 per cent in New Zealand (Forster et al., 1973). There are many
reports on the visits of insect pollinators on Brassica oleracea (Rauala, 1972; Dhaliwal
and Sharma, 1973; Muhammad et al. , 1973; Adlakha and Dhaliwal, 1979; Kakkar, 1981;
1983, Tewari and Singh 1983; Varma and Joshi, 1983; Kumar et al. , 1988; Mishra et al. ,
1988). From Indian sub-continent, Apis cerana , A. dorsata and A. florea are all
important although to various extents in different localities. Solitary bees and Eristalis
101
spp. are also locally available. Thirty-four species of insects, including honeybees,
visited the cauliflower bloom at Solan (Himachal Pradesh), India (Sharma et al. , 1974).
Eighteen insect species belonging to fourteen families under five orders were found
visiting blossom of cauliflower at Hisar, Haryana, India by Priti and Sihag (1997).
Abelmoschus esculentus L. (Okra)
Mishra et al. (1987) studied pollination requirement of 9 cultivars of okra at Solan.
Ants were reported as frequent visitors (44.35%) followed by A. cerana (21.25%). Other
v i s i t o r s i n c l u d e d d i p t e r a n f l i e s , h y m e n o p t e r a n s a n d b e e t l e s . H o w e v e r, o n l y
Ceratina sexmaculatus , Megachile sp., Xylocopa sp. and Bombus spp. were important
pollinators.
Allium spp. (Onion)
Honeybees have been reported as the most frequent visitors of onion bloom (Treherne,
1923; Trofimec, 1940; Agati, 1952; Bohart et al. , 1970; Caron et al., 1975). Other visitors
to the bloom of this crop were dipteran and Solitary bees. Wild bees and dipterans
(Lederhouse et al. , 1968) and Halictus farinosus (Parker, 1982) were reported as most
abundant foragers of onion bloom in New York state and Utah, respectively. In India,
bees Apis cerana, A. dorsata , A. florea and Trigona iridipennis were reported as primary
insect pollinators of onion (Singh and Dharamwal, 1970; Jadhav, 1981 and Rao and
Suryanarayana, 1989). Kumar et al. (1985) found that three onion species, A. cepa , A.
fistulosum and A. cepa fistulosum were greatly benefited by insect pollination and A.
cerana and dipteran flies were predominant insect visitors.
Daucus carota L. (Carrot)
Carrot flowers are visited by different types of insects. Bohart and Nye (1960) collected 334 species belonging to 71 families on carrot flowers at Logan, Utah, USA. The
pollen gathering honeybees were most valuable than nectar gatherers. In Moscow,
Pankratova (1958) found that dipteran comprised 90 per cent and honeybees 9 per cent
of the insect visitors to carrot bloom. But dipteran were found to collect nectar only.
Galuszka and Tegrek (1987) observed that honeybees did not visit carrot crops when
more attractive flower species are blooming in the vicinity. Kumar et al. (1989) recorded
20 species of bees belonging to 8 genera of 6 sub-families and 4 families on carrot
flowers. Most frequent visitors were H. splendidulus , Allodape sp., Nomioides sp., H.
vachallii and H. himalayensis . On the basis of pollination indices, Halictus splendidulus
was found to be the most efficient pollinator (Kumar and Rao, 1991).
Pollination Efficiency
Pollination efficiency of different insect pollinators has been evaluated on the basis
of number of characteristics. However, it is recognized that there are inherent differences in the ability of various species to effect pollination in spite of their abundance.
Therefore, efficiency of an insect species as pollinator has also been attributed to its
foraging behaviour and the amount of loose pollen grains adhered to its body (Bohart
and Nye, 1960; Free 1993). Pollination indices calculation on the basis of relative
abundance, foraging behaviour (foraging speed, rate, amount of loose pollen carried on
102
the body has been found as an alternate parameter to evaluate the pollination efficiency
(Sharma, 1990). Sihag and Rathi (1994) have also suggested formula for calculating
performance scores of insect visitors on different pollination attributes.
Foraging behaviour
Nectar robbing in cauliflower bloom by many honeybee foragers has been found in
Solan India by Kumar et al. (1994). Side foraging of cauliflower nectar by A. cerana and
A. mellifera and of Okra nectar by A. cerana has been reported by Kapoor and Dhaliwal
(1989) and Mishra et al. (1987), respectively.
Foraging speed and foraging rate
Foraging speed (time spent per flower) and foraging rate (number of flowers visited
per minute) depends upon the foraging behaviour of insects and floral structure of the
crop concerned, particularly the corolla depth (Gilbert, 1980). Free and Williams (1973)
reported that honeybees spend 131 s per kale flower when collecting pollen loads, and
94 s when collecting nectar only. Halictus spp., Andrena ilerda and Apis florea visited
3.5, 7.5 and 6.0 flowers per minute (Rahman, 1940). Higher number of flowers of
cauliflower were visited per minute by A. dorsata followed by A. mellifera, A. cerana,
Eristalis spp., Ceratina spp., Halictus sp. and Lasioglossum sp. (Kakkar, 1983).
Amount of pollen on the bodies
The number of loose pollen grains on the body of insect visitors depends upon the
size of insect and the condition in which the pollen load is carried. According to Erickson
and Peterson (1979 a, b) 14666 and 9582 carrot pollen grains were found on the body of
pollen gatherers and nectar gatherers, respectively. Priti and Sihag (1997) found that on
cauliflower bloom A. dorsata carried the maximum and Musca domestica the minimum
number of loose pollen grains. Hymenopteran carried more number of pollen grains than
dipterans. Pollen grain carrying capacity varied in different foraging group of honeybees.
Kumar et al. (1993) found that nectar gatherers of honeybees carried pollen grains either
equal to or greater than pollen gatherers on toria and cauliflower. Other workers have
found more pollen grains over the body of pollen gatherers of honeybees than the nectar
gatherers on cauliflower (Dhaliwal, 1980; Kapoor, 1983) and onion (Kumar et al. , 1985).
However, Eristalis tenax carried significantly higher number of pollen grains than Apis
spp. and other insect visitors on onion (Kumar et al. , 1985).
Role of insect pollinators in seed set
Estimates of increased seed set due to pollinators have been made in different parts
of the world. An increase of 22-100 per cent; 100-300 per cent, 100-125 per cent, 91
to 135.4 per cent and 353.5 to 9878 per cent in the seed yield has been reported due
to assured pollination by bees in radish, cabbage, turnip, carrot and onion crops,
respectively (Singh, 1997). The results of such studies on important vegetable crops is
given below :
B. oleracea
An increase of 300 per cent in seed crop of cabbage was reported due to insect
103
pollination by Radchenko (1966). Effects of insect pollination are much greater from
India, Pakistan and Bangladesh. Rauala (1972) reported 68 per cent and 9 per cent set
in cages with and without bees, respectively. Increased seed set (129%) was found due
to presence of honeybees by Muhammad et al. (1973). Sihag (1986) found that plants
caged to exclude insects and plants not caged produced 13 and 978 pods per plant.
Similarly, 9.0 and 11.5 seeds per pod in caged (without insects) and open plots were
found by Alam et al. (1987). Tewari and Singh (1983) demonstrated a decrease in seed
set and yield with increasing distance from three A. cerana colonies. Kumar et al. 1989
found significantly higher seed set and seed weight in open pollinated than in bagged
flowers in 5 cultivars of cauliflower.
Abelmoschus esculentus
A positive correlation between the number of seeds in a pod and its weight, and
insect pollination increased the number of seeds present in a pod (Free, 1976).
Nineteen per cent increase in yield in Punjab, India was reported by Tanda (1984, 1985)
due to intensive bee pollination. Mishra et al. (1987) found that the weight and length of
capsules and seed number per capsule were significantly higher in open pollinated than
in bagged flowers.
Allium spp.
In Poland, Woyke (1981), found that plots in an open field were caged without bees,
caged with bees and not caged produced 2, 210 and 669 seeds per head, respectively.
In India, Kumar et al. (1989) found greater set and yield and better seed germination
from plots caged with bees, than from plots caged without bees and open plots (61, 90,
72 % and estimated seed yield of 73, 275, 97 kg/ha respectively on plots caged without
bees, caged with bees and not caged). Rao and Suryanarayana (1989) have reported
higher seed yield in onion due to placement of bee colonies.
Pollination for Hybrid Seed Production
Honeybees are going to play increasing role, not only in the pollination of the crops,
but also in specialized field like hybrid seed production. Honeybees have been used for
this purpose in onion (Woyke and Dudek, 1983; Woyke, 1981), cabbage (Kubisova et
al. , 1987), cauliflower (Woyke, 1989; Gupta et al. 1984) carrot (Erickson and Peterson,
1979 a,b; Galuszka and Tegrek, 1987; Rodet et al. , 1991), cucumber (Ruszkowski and
Bilinski, 1984).
Pollination in Green Houses/cages
Honeybees, bumble bees, solitary bees, syrphids and blowflies have been used to
pollinate flowers in the green houses, glass houses or cages. Bumble bees are valuable
for use in small enclosures and can be readily obtained from flowers or by collecting
their nests. They forage at low temperatures at which honeybee activity is limited. These
bees have been used in many vegetable crops. Use of honeybees in green houses has
increased. They have been used to pollinate Brussels sprout, muskmelon, onion, runner
bean, tomatoes etc. in green houses or in large pollination cages (Mishra et al. , 1997).
104
1
Maintaining Insect pollinators population
Insect pollinators population including honey bees can be maintained and enhanced
on agricultural crops following ways :
Increasing Pollination visitation: Insect pollinator visitation can be increased by either enhancing local populations of native pollinators or by supplementing pollinator
populations with commercially managed species.
Enhancing populations of native pollinators : Pollinators visitation to flowering crops
in particular area can be enhanced through habitat management. These strategies should
be directed towards the member of pollinator guild that are most efficient with low annual
variation in population. Pollinators can also be provided with appropriate nesting materials and site for overwriting and mating. Cropping practices can also be altered which
suit the characteristics of pollinators. Timing of planting dates so that flowering periods
coincide with peak population of pollinators is also helpful.
In commercial crop pollination under Indian scenario honeybees are being
managed effectively and economically. The honeybees large population, transportability,
year round availability and broad dietary preferences at the colony level along with floral
constancy of individual foragers make it the pollination of choice for a wide range of
crops. Else where in the world, several solitary species of bees have also been exploited
successfully for crop pollination, including alkali bee ( Nomia melanderi), leaf cutter bee
( Megachile rotundata) and orchard bee ( Osmia sp.).
Maintaining pollinators population on target crops
Pollination of the target crop can be reduced if crops weeds blooming in
proximity provide greater rewards in terms of nectar and pollen to the bees. This can be
managed or reduced by following methods :
Timing of pollinator Introduction: Managed pollination can be conditioned to a
particular crop in a particular area by moving bee colonies to crops after the
initiation (5-10%) of flowering. Shifting honeybees too late can be detrimental
because flowers produced early in the season are not pollinated, which can reduce
yields. Shifting bees too early to the target crop may condition foragers on
some other crop blooming prior to target crop. This can also have direct impact of
pollination of the target crop.
Plant Breeding and Agronomic practices: Honeybees and other insect pollinators
forage on the most attractive source available under long term selective breeding
programmes. Characters of crop responsible for making it more attractive to bees
should be taken into consideration. Most insect pollinators forage on flowers to
collect nectar, pollen or both. Thus, selection of plants with enhanced quality and
quality or accessibility of nectar or pollen rewards will improve the attractiveness of
plant to pollinators. Pollinators visits also depend on other characters like floral
colour, the number of flowers per inflorescence and odours. Thus enhancing visual
105
1
and olfactory cues are also effective. Nectar production is influenced by external
factors affecting plotosynthesis and plant growth. Thus, proper fertilization can increase the attractiveness of crops. Watering increases nectar production in crops
such as radish, cauliflower which will have direct impact on the insect visitation.
Suggested Readings
Adlakha, R. L. and Dhaliwal, H. S. 1979. Insect pollination of seed cauliflower (Brassica
oleracea var. botrytis) with special reference to the role of honeybees. Indian
Bee J. 41 : 13-16.
Bohart, G. E. and Nye, W. P. 1960. Insect pollinators of carrots in Utah. Bull. Utah agric.
Exp. Stn. 419.
Dhaliwal, H. S. and Sharma, P. L. 1973. The foraging range of the Indian honey bee on
two crops. J. Apic. Res. 12 : 131-143.
Free, J. B. 1976. Insect pollination of tropical crops. Report of the Central Association
of Beekeepers .
Free, J. B. 1993. Insect Pollination of Crops . 3rd Edn. Academic Press, London.
Kumar J., Gupta, J. K., Mishra, R. C. and Dogra, G. S. 1988. Pollination studies in
some cultivars of cauliflower ( Brassica oleracea var. botrytis L.). Indian Bee J .
50 : 93-95.
Kumar, J., Rao, K. V. K., Gupta, P. R. and Dogra, G. S. 1989. Indian Bee J . 51 (2)
: 55-58.
Kumar, J., Rao, K. V. K. and Gupta, J. K. 1993. Amount of loose pollen on the body of
bees visiting spring blooming crops. J. Insect Sci . 6 (2) : 259-263.
106
SCOPE AND LIMITATION OF INSECT POLLINATIONS
IN PROTECTED CULTIVATION
Ombir
Department of Entomology,
CCS Haryana Agricultural University, Hisar
Insects play a vital role in the pollination of many plants including some of our most
important cultivated horticultural crops. The most common pollinators being used in the
greenhouses are the bumblebees ( Bombus sp.) and honeybees ( Apis sp.) In general,
insects other than bees usually visit only specific crops, only at specific times, and play
a minor role in pollination. However, bees are dependent upon nectar and pollen for the
survival of the colonies and therefore visit numerous flowers as long as they have pollen
and/or nectar. The value of honeybees is also limited in the greenhouses especially
during the cold seasons or winter months. They do not forage at air temperatures below
13 oC, and at low light intensities. Moreover, greenhouses are frequently treated with
insecticides and there is practically no insect activity especially during the winter and
early spring seasons. Therefore, there are serious problems in pollination of crops grown
under protected/greenhouses conditions. The growers either use hand pollination or introduce honeybees/bumblebees for pollination of crops.
Pollination is the pre-requisite of sexual mode of reproduction in the angiosperms. It
may be either self or cross. The act of transfer of pollen from stamen to the receptive
stigma of the same flower or from different flower of the same plant species is known as
pollination. The transfer of pollen grains from anther, to stigma of the same flower is
known as autogamy (self pollination) and transfer of pollen gains from anthers to different flower is known as allogamy (cross pollination). Monoaecy, dioecy, dichogamy, selfincompatability, self-sterility or a combination of this mechanism promotes the crosspollination. In cross-pollination wind (anemophily), water (hydrophily) and animals
(zoophily) may transfer the pollen.
Now a days, the growing of off-season vegetable and highly priced crops are increasing. These crops are grown under polyhouse/greenhouse conditions which are also known
as protected cultivation. To grow a successful commercial crop, complete fruit set with
suitable size is quite essential for better economic returns under polyhouse/protective
cultivation. In cross-pollinated crops pollinators are absolutely necessary for fruit set
and seed formation. But the protected cultivation does not allow the insect pollinators to
pollinate the crop as in open fields. So, to pollinate the crop in polyhouse/cages/greenhouse honeybees, bumblebees are to be introduced in polyhouses for pollination :
i)
To produce the crop under artificial conditions.
ii) To produce pure seed.
iii) For plant breeding studies.
Honey bees ( Apis spp.) are usually preferred to other pollinators to pollinate the
entomophilous crops which are visited by honeybees in polyhouse/greenhouse/cages.
107
The honeybees are easily available in large populations, active round the year and can
be managed efficiently with little inputs. The individuals of honeybees exhibit considerable fidelity and consistency to flowers. In Japan, about three-quarters of the honeybee
colonies used for pollination are concentrated on strawberry production in green houses.
In Israel, the only pollinator used for melon pollination in green houses is the Apis
mellifera . Bumble bees are also very usefully employed for pollinator of crops in
protected cultivation particularly for tomato in Isreal and European countries as Bombus
spp. thrive well in temperate regions. They are also known for buzz pollination. Other
pollinators which can be useful for pollination of crops in enclosures are stingless bees
( Trigona spp.) in our country. Stingless bees are better pollinators of some crops than
honeybees. They thrive much better in tropical areas. Stingless bees are polylectic (pollinate many types of crops).
While using the bees as pollinators in polyhouse/greenhouse/cages, following points
should be taken care of for effective pollination in enclosures :
a ) Polyhouse/Caging effect :
A cage may affect the plant growth by influencing its micro and macro environments.
Different types of cages may have a variable effect on the light intensity, temperature,
humidity and wind speed depending upon the weather and climatic conditions. This influences the activity of honeybees in cages and polyhouse. Probably large and well
ventilated cages/polyhouse has little effect on the environment than small cages and
honeybees do their foraging activity and pollinate the crop properly.
b) Construction material for enclosures :
Honeybees forage well in air inflated polyethylene 'bubble' greenhouses, nylon screen
cages erected within fibre glass greenhouses and inside large polyethylene tunnels but
unable to forage in greenhouses made of ultraviolet opaque polymethyl methacylate
sheet and fibre glass.
c) Type of bees for caging
When the colonies are first caged or put in greenhouses, it should be of 3-4 frames
strength and the most of honeybees should be <20 days of age and should not be from
foragers in the fields. Those bees, which are already foragers they try to escape from
the enclosure hence remain flying/darting against the walls of enclosures, fail to return
to hive and die but on the contrary the young bees, which learn foraging inside the
enclosure after introduction effectively, forage and pollinate the crop and do not try to
escape, so do not dart against walls of enclosures.
d) Colony strength
Colonies with three or four frames having reward, brood and bees are sufficient for
pollination in cages/polyhouse/greenhouse. Using too large colonies (= 10000 bees) in
cages may badly damage the anthers, stigmas. So use of ideal low strength colonies (=
2000 bees) is advocated. If needed additional frames of emerging bees may be added.
108
e ) Sustaining the caged colonies
In the cages/polyhouse/greenhouse sufficient reward is not available for the proper
development of honeybee colony because there is less area and numbers of flowers are
not sufficient to provide sufficient amount of pollen and nectar for the bees. So colonies
confined in cages may dwindle in strength owing to scarce forage. Hence, provide artificial food to confined bees off and on, or locate the colony one gate inside and outside of
the cage so that bees can forage freely both inside and outside. However, this method
fails where contamination inside the cages with foreign pollen is to be avoided. Feeding
sugar syrup to the colonies inside cages of greenhouses stimulates pollen collection
and hence probably results in more pollination.
f)
Production of pure seed
To produce pure seed in cages/polyhouse/greenhouse the contamination of pollen of
other varieties should be avoided. To avoid contamination, confine the bee in colonies
for 12 to 48 h by which we get viable pollen free bees for introduction into enclosure for
pollination of crops. The period of confinement of bees depends on the duration of viability of pollen sticking to the bees' body. In Brassica oleracea, the viability of body pollen
decreased to 0.5-1.5 per cent after foragers had spent 22h in their colony. Foragers that
were caged for 24h away from the colonies retained more body pollen, 9-20 per cent of
which was still viable.
g)
Location of colony
To get an even distribution of honeybee foragers on a greenhouse crop, it is better to
have a single colony at the centre of a greenhouse than at one end. This will improve the
foraging activity as the bees can forage in all the directions at short distances, which
will ultimately improve the pollination.
Suggested Readings
Dag, A. and Eisikowitch, D. 1999. Ventilation of greenhouses increases honey bee foraging activity on melon (Cucumis melo). J. agric. Res . 38 (3-4) : 169-175.
Faegri, K. and Pijl, L. Vander, 1979. The principles of pollination ecology . Pergamon
Press Ltd.
Free, J. B. 1993. Insect Pollination of Crops . Academic Press, London.
109
ROLE OF INSECT POLLINATORS IN SEED PRODUCTION
OF SEED SPICES
S. S. Sharma and Hasansab A. Nadaf
Department of Entomology,
CCS Haryana Agricultural University, Hisar 125 004
There are about twenty seed spices; among them important are coriander, cumin,
fennel, fenugreek, ajwain, dill, celery, anise, nigella and caraway. The other seed spices
are poppy seeds, rai, yellow mustard, white mustard, parsley, sesame and shyah zeera .
Most of the seed spices are grown in the entire country. However, Rajasthan and
Gujarat have emerged as a hub for the seed spices production by growing 80% of
the crop cultivated in India. India had earned Rs. 5440 millions during 2008-09 by exporting 52,550 tonnes seed spices to various countries. This is all time high both in terms of
value and quantity. The world demand is poised to increase ten times in the next five
years and this presents an excellent commercial opportunity for the country (Vision,
2030).
Seed spice crops heavily dependent on insect pollinator for pollination and seed
settings. Honey bee play very significant role in pollination of seed spice crops,
for qualitative and quantitative improvement of seeds. In multiple agro-ecosystems and
ecologies, pollinator-friendly management practices have been identified that serve to
enhance yields, quality, diversity and resilience of cropping systems :
Preserving wild habitat.
Managing cropping systems, flower-rich field margins, buffer zones and permanent
hedgerows to ensure habitat and forage.
Cultivating shade trees.
Managing for bee nest sites, e.g. by leaving standing dead trees and fallen branches
undisturbed.
Reducing application of pesticides and associated risks.
Establishing landscape configurations that favour pollination services.
The role of insect pollinators in various spice crops seed production is as follows :
Cardamom (Small), Elettaria cardamomum
It is an important commercial crop depending on bees for pollination. Here yield
increases up to 21 to 37 per cent. Apis cerana is the most abundant visitor to cardamom
flowers in India, followed by A. dorsata , A. florea and Trigona spp. For effective
pollination in cardamom, four bee colonies per hectare are required.
Onion, Allium cepa
Honey bees are effective pollinators of open pollinated onion because both pollen
and nectar are available on all umbels. The two colonies of honey bees delivered when
flowering is well started, then an additional two per acre at 3 to 4 day interval to take
110
advantage of naïve bee behaviour and maintain some level of nectar foraging activity
throughout the blooming period.
Clove, Syzigium aromaticum
Tidbury (1949) stated that the flowers are visited by bees but no known attempts
have been made to use pollinating insects in clove production.
Coriander, Coriandrum sativum
Bogoyavlenskii and Akimenko (1966) associated seed yield with greater insect
visitation. Honey bees are apparently ideal pollinators of Coriander. In coriander yield
increases up to 187 per cent due to pollination.
Fennel, Foeniculum vulgare
Narayana et al. , (1960) found that the Apis florea constituted 81 per cent of the
visitors to fennel in India and they recommended that cultivars more attractive to bees
be developed. They also recommended keeping of colonies of honeybees around or in
fennel field.
Vanilla, Vanilla spp.
In its native Mexico the flowers of vanilla are pollinated by small bees of the genus
Melipona and also by humming birds. There are no recommendations for the use of bees
or other agencies but the saturation pollination by certain bees offer possibilities
because vanilla in Mexico is probably pollinated by bees at one time to some extent.
Cumin, Cuminum cyminum
The honey bees in cumin not only increase the production of cumin but also gives
honey which is viscous, contain higher quantity of iron and unsaturated sugar with
attractive aroma.
Anise, Pimpinella anisu
Wahab et al. , (2011) concluded that open pollination produced the highest
significant weight of seeds/feddan (1024.12 kg) followed by honeybee pollination (781.55
kg), but insect exclusion plots were of the lowest value (300.24 kg).
Caraway, Carum carvi
Because of the protandry, pollen must be transferred from pollen- producing flowers
to receptive stigmas. The pollen is not windblown but must be transferred by insects.
Bees are the primary pollinators of caraway flowers. Although there are no recommendations on the pollination of caraway, the flower type and the need for pollinating insects
would indicate that where maximum commercial production of seed is desired the grower
should provide an ample supply of bees to the field.
Black seed, Nigella sativa
According to Munawar et al., (2009), visits of honeybees ( Apis mellifera ) in black
seed increased the number of seeds set and yield produced but had no effect on the
weight of seed produced. Thus strategies to promote pollination by honeybee may be
helpful in enhancing seed yield in N. sativa and possibly in other related species.
111
Dill, Anethm graveolens
Both flies and bees have been mentioned as pollinators of dill. If seed is grown
commercially, there are probably not enough flies in the vicinity to pollinate all the
flowers. Honey bees can be moved to the field and doubtless this should be done if the
highest seed production is desired.
Celery, Apium graveolens
Because of the attractiveness of the flowers to honey bees, these insects are probable the most satisfactory as pollinating agents, provided they are present in abundance. No information is available on the desired population density of pollinators on
celery, but eight bees per square yard suggested fro carrots (Hawthorn et al. , 1996)
should be satisfactory.
Sesame, Sesaum indicum
Honey bees are the primary visitors to sesame flowers. Langham (1944) stated that
the bees alight on the protruding lip of the flower and squeeze inside. Later, it emerges
coated with pollen and flies to another flower. However, no benefit from such crossing,
although established in many other crops that have been considered self pollinating,
has been established for sesame.
Suggested Readings
Hawthorn, L. R., Bohart, G. E. and Toole, E. H. 1960. Carrot seed production. Utah
Agriculture Experiment station Bulletin . pp. 18.
Langham, D. G. 1944. Natural and controlled pollination in sesame. Journal of Heridity.
35 (8) : 254-256
Munawar, M. S., G. Sarwar, S. Raja, E. S. Waghchoure, F. Iftikhar and R. Mahmood.
2009. Pollination by honeybee ( Apis mellifera) increases seed setting and yield
in black seed ( Nigella sativa ). International journal of Agriculture Biology . 11 :
611-615.
Narayana, E. S., Sharma, P. L. and Phadke, K. G. 1960. Studies on requirements of
various crops of insect pollinators. Insect pollinators of saunf ( Foeniculum Vulgare)
with particular reference to the honeybees at Pusa (Bihar). Indian Bee Journal .
22 (1/3) : 7-13.
112
ROLE OF INSECT POLLINATORS IN TROPICAL/
SUB-TROPICAL/ARID FRUIT CROPS
H. D. Kaushik, Sunita Yadav and Hasansab A. Nadaf
Project Coordinating Unit, AICRP on Honey Bees & Pollinators
CCS Haryana Agril. University, Hisar 125 004
The subtropics are the geographical and climatical zone of the earth immediately
north and south of the tropical zone, which is bounded by the Tropic of Cancer and the
Tropic of Capricorn, at latitudes 23.5°N and 23.5°S. The term "subtropical" describes
the climatic region found adjacent to the tropics, usually between 23.5 and 40 degrees
of latitude in both hemispheres. The important fruit crops of subtropics include
Avocado, Citrus, Grape, Litchi, Loquat, Mango, Olive, Passion fruit, Persimmon and
Pomegranate. A tropical climate is a climate of the tropics. In the Köppen climate classification it is a non-arid climate in which all twelve months have mean temperatures
above 18°C (64°F). Unlike the extra-tropics, where there are strong variations in day
length and temperature, with season, tropical temperature remains relatively constant
throughout the year and seasonal variations are dominated by precipitation. The fruit
crop of tropical climate includes Banana, Guava, Papaya, Pineapple and Sapota. Arid
and semi-arid or subhumid zones are characterized by low erratic rainfall of up to 700mm
per annum, periodic droughts and different associations of vegetative cover and soils.
The fruit crops of this region are Aonla, Ber, Custard apple, Date Palm, Fig, Jack fruit,
Jamun and Phalsa. The role of various insect pollinators in important subtropial, tropical
and arid/semi arid fruit crops is mentioned below.
Tropical fruits
Banana, Musa paradisiaca
Among the insects visiting banana inflorescence, the honeybees ( Apis cerana, A.
mellifera and A. dorsata ) were the dominant visitors (77.50%) followed by the wasps
(Polistes haebraceous & Vespa orientalis) with 15.53% visitation. The remaining insect
visitors comprised of other hymenoptran insects including the sting less bees. Comparing with other insects the honeybees had higher visits (76.8-87.3%) in afternoon hours
(1.15-7.15 pm) than in forenoon hours (73.2-77.4%). The honeybees and the wasps started
foraging banana flowers for nectar early in the morning (5.15 am). At this hour maximum
number of visitors were the honeybees A. cerana with an abundance of 5.10 bees/min
followed by A. dorsata (1.80 bees/min), P. haebraceous (1.30 wasps/min), V. orientalis
(0.80 wasp/min) and A. mellifera (0.30 bee/min).The honeybees were recorded to forage
banana inflorescence at all the observational hours indicating availability of ample
nectar throughout the day. Among the honeybees, A. cerana and A. dorsata were
more active in forenoon with mean abundance of 3.10-6.20 and 0.30-1.80 bees/min,
respectively, whereas A. mellifera was more active in afternoon hours with mean
abundance of 2.60-3.70 bees/min. Throughout the blooming period, maximum mean
abundance was for A. cerana (2.88 bees/min) followed by A. mellifera (2.21 bees/min),
P. habraceous (0.78 wasps/min) and A. dorsata (0.50 bees/min).
113
Guava, Psidium guajava
The fragrant white flowers are bisexual and self-fertile. Anthers are numerous and
produce a large number of pollen grains. Honey bees were the best pollinators and
increase in fruit set was achieved, the quality of fruit was also improved (Lakshmi and
Mohan Rao, 1998). They reported 26 to 43 per cent of pollination was due to honeybees.
Bees visit flowers for nectar and pollen and although flowers are self-compatible, crosspollination gives higher fruit yields. Honey bees collect nectar and pollen from 6 am to
11 am. The peak activity is about 9 am.
Apis cerana (53.20%), A. mellifera (70.7 %), Xylocopa leucothorax (9.00%), Polistis
haebrius (7.30%), Vespa magnifica (5.40%), Papilio demoleus (5.40%), Musca domestica
(7.00%), Oecophilla smagdina (4.00%) were recorded foraging the flowers of Guava at
Johrat, Assam. Average Apis cerana forager is 4.78±0.69 with maximum of 8.70±1.05
during 09.00-10.00 hrs. and lowest (1.90±0.35) at 13.00-14.00 hrs. Frequency of flower
visit per minute by A. cerana was found to be 9.81±0.98. The highest frequency of visit
per minute was found to be 18.70±1.16 at 0900-1000 hrs. of the day and the lowest was
observed to be at 13.00-14.00hrs.having 1.80±0.25 visit per minute. The average time
required for foraging per flower was found to be 10.51±1.02 seconds. The maximum time
spent per flower was recorded to be 17.50±1.61 seconds during 0800-0900 hours and
minimum time spent was recorded to be 4.90±0.55 second during 1300-1400 hours of
the day. There was significant increase in fruit set and yield of guava in bee pollination
treatment (88.74%, 86q/ha) over without bee pollination (39.74%, 41.30q/ha) and fruit
characteristics were also significantly improved in length and girth in bee pollination
treatment over without bee pollination (Anonymous, 2011).
Sehgal (1961) observed a high percentage of fruit set under natural conditions in
diploid varieties of guava (80-86 %) as compared to triploid varieties (54 %).
Papaya, Carica papaya
For papaya fruit to develop, pollen must be transferred from the staminate (male)
flowers to the pistillate (female) flowers. The fruit may produce 1,000 or more seeds and
so well over 1,000 pollen grains must be deposited on the stigma while it is receptive.
Fruit with less than 300 seeds is usually not marketable, and the more seeds the larger
the fruit (McGregor 1976).
There is a significant observation of earlier research which describes the pollination
of papaya by insects, however, results vary as to which insects (if any) are the most
important. Some have considered wind to be the primary agent for pollination while others argue a combination of wind and insect pollination is needed for optimal pollination
and still others give credit to a number of other insect including the hummingbird moth
( Macroglossum stellatarum ) and various species of Trigona and Xylocopa (McGregor
1976). More recently (Garrett 1995) reported that the hawk moth was the primary
pollinator in Queensland orchards.
Conflicting evidence persists with reference to the pollinating capabilities of honey
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bees in papaya orchards with more recent research by Westerkamp and Gottsberger
(2000) found that attractive nectar produced by male flowers around the rudimentary
pistal is out of reach of the bees because of the long tube. Research by Walsh et al.
(2006), however, highlighted the importance of insects in general in the pollination of the
papaya. In the study, three types of netting (coarse, medium and fine mesh) were evaluated for exclusion of insects to control phytoplasma diseases of papaya. Results showed
that pollination was poor under netting, with the individual fruit weight and total
harvested fruit weight reduced to around 50% compared to the control.
Subtropical fruits
Mango, Mangifera indica
Young (1942) made pollination studies on the 'Haden' mango in Florida and found no
significant difference between percentages of fruit set in self- and cross-pollinated
flowers. Sturrock (1944) also considered the flowers self-fertile and this self-fertility was
supported by the earlier work of Popenoe (1917), who stated that the mango is selffertile but cross-pollination increases fruit set. In contrast, Singh et al . (1962) reported
that crossed flowers set fruit whereas self-pollinated ones did not, indicating a degree of
self-sterility. The actual degree of self-fertility and sterility in individual cultivars has not
been determined, but there is apparently some variation. Self-sterility has not, however,
been identified as a major problem for percentage fruit set. Whatever the degree of selfsterility within a cultivar, there is a definite need for pollen to be transferred to the stigma
by an outside agent. Popenoe (1917) stated that some embryos are capable of development without fertilisation, however Naik and Rao (1943) obtained no fruit set of more
than 100,000 flowers studied. Fraser (1927) stated that fruit bud formation and pollination were the two big problems in growing mangoes and Wolfe (1962) concluded that
getting fruit to set was more difficult than getting trees to produce flowers. The evidence
indicates that the need for cross-pollination between mango cultivars is not critical, at
least for most cultivars, but there is need for pollinating insects to transfer the pollen
from anthers to stigma within the cultivar to obtain satisfactory crops of fruit.
Several more recent studies give indications to the effectiveness of honey bees in
pollinating mango crops. Du Toit (1994) found that fruit set was poor in both openpollinated and bagged inflorescences when honey bees were introduced into a South
African mango orchard. Singh (1989) had contrasting findings, showing that several
foraging insects including the European honey bee significantly increased fruit set. Farjado
et al. (2008) found that after the introduction of bee colonies, fruit set in uncaged
inflorescences (41%) was significantly higher than that in caged inflorescences (0.7%).
Litchi, Litchi chinensis
Many studies have shown significant increases in yield of lychee crops as a result of
honey bee pollination. Badiyala and Garg (1990) introduced four honey bee colonies into
a lychee orchard in India at the start of flowering and recorded fruit set two to three
times higher in inflorescences open to honey bees compared to those that were bagged
to exclude them. Similar results were recorded in South Africa by DuToit (1994) with a
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fruit set three times greater when inflorescences were open to honey bees.
In a study conducted at Johrat, Assam revealed that Apis cerana @ 5 colonies/ha
produced significant yield of 66.7 q/ha against 55.4 q/ha in open pollination and 29.88
q/ha in without bee pollination. There was 123.27% increase in yield in bee pollination
over without bee pollination and 31.82 per cent over open pollination (Anonymous 2009b).
Litchi is considered to be the major bee flora during honey flow season in the Kangra
area of Himachal Pradesh. Pollination studies were carried out in litchi in Dhaulakuan in
District Sirmour and Kangra. The important pollinators included Apis mellifera, A.cerana,
A. florea, A. dorsata, Episyrphus balteatus, Melipona sp. Under these studies, there
was no impact of placing additional colonies since under Dhaulakuan conditions the
population of natural pollinators on litchi was sufficient.
In the studies on pollination of litchi in Jorhat, Assam, we observed on average of
20.67 forager bees of Apis cerana visiting litchi blooms in a square metre area per minute.
The bees visited 19.24 flowers in a minute and took 3.44 seconds to forage on a flower.
Bee pollination resulted in an average yield of 64.45 fruits per branch that weighed 20.55
g. while the flowers that had no bee visits yielded 26.49 fruits weighing 13.98 g per
branch. Fruit yield per hectare was 70 tons in bee pollinated plots, compared to 36.8
tons in self pollinated plots (Mahanta & Rahman, 1997).
Population dynamics of different insect foragers was studied on litchi. Litchi chinesis
(Gertn.) Sonn., blooms at Pusa (Samastipur), Bihar. India Apis cerana F. was the most
dominant forager while the lowest foraging activity was shown by Apis mellifera L.
Maximum foraging rate of the former was observed on March 15, 1993 when the
temperature ranged from 16.0 to 34.4 oC and a relative humidity from 29 to 58 per cent.
Their foraging rate was positively correlated with temperature while a non-significant
native correlation was observed with relative humidity (Mishra & Yazdani, 1997).
The attractiveness of bees to flowers of four varieties of litchi in Udheywalla, Jammu,
India was found to be significantly related to progression of bloom density. Abundance
of pollinating bees followed the same general pattern as the floral density of litchi trees.
Floral rewards were also found to influence the foraging population of insects visiting
litchi flowers. Cultivars with higher caloric rewards were highly attractive to bees and the
attractability pattern was Calcutta } Dehradun } China Shahi } Seedless. The studies
suggest that abundance of resources and energy pattern decisively shape the behavior
of pollinating insects (Kitroo & Abrol, 1996).
Citrus, Citrus spp.
The pollination requirements for citrus are quite diverse (Sanford 2003; McGregor
1976), ranging from self-fertile (Valencia oranges) to almost complete self-sterile (mandarin and mandarin-hybrid complex). Pollen must be transferred to these self-sterile or
partially self-sterile flowers from those of another compatible type for maximum fruit
production (Sanford, 2003). In others (Washington navel oranges), the plant is benefited
if pollen is moved from flower to flower within the cultivar or within the species (Sanford
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2003), and finally others such as lemons, have no known benefit from transfer of foreign
pollen to the stigma (Sanford, 2003; McGregor, 1976).
The literature contains conflicting reports on the need for bees in some citrus varieties and therefore it is difficult to make generalisations regarding the responsiveness of
citrus crops to honey bee pollination. Factors such as the variety, conditions at the site
and honey bee pollination may all contribute or alternatively, have no effect in increasing
yields, fruit size and seed number.
Some have suggested as citrus flowers have both male and female parts on the
same flower (complete or perfect flowers) that they will generally pollinate themselves
and produce fruit (i.e. they are self-compatible and self-fruitful). There are, however, a
few special cases with tangelo and tangerines where a pollinator is required for good
fruit set. Citrus trees produce an abundance of flowers. Citrus has a natural tendency to
drop its fruit, and most of the fruit set at bloom will not hold on until maturity. A good
crop may be borne if only 3-7% of the flowers that are set yield mature fruit.
India has a diverse insect pollinator's fauna. In addition to Apis species, other non
Apis bees like Halictid, Colletid, Andrenid, are present in many parts of India. The country is a leader in Asia in field of pollination research using native bees (Rao, 1997).Bee
pollination increased yield and fruit quality in Citrus (Gupta et al., 2000). Bee pollination
did not only increase the fruit set but also reduced fruit drop in citrus (Dulta and Verma,
1987 and Partap et al. , 2000). Reports have also indicated an increase in fruit juice and
sugar content in citrus fruits (Partap, 2000).
The bee pollination treatment i.e. Apis cerana @ 4 colonies / ha gave the significant
yield of 50.8 q/ha against 44.12 q/ha in open pollination and 32.9 q/ha in without bee
pollination. There was yield increase of 57.14% yield in bee pollination over without bee
pollination and 15.14% over open pollination (Anonymous 2011). The overall fruit set was
significantly higher (31.44 %) under open pollination as compared to self pollination
(22.86%). However, fruit set in Kinnow was higher (52.22%) than other Citrus spp. There
was no fruit set in sweet lime (Dhankar et al., 1999). At Jachh, Himachal Pradesh
pollination studies on Malta, Sangtra and Kinnow revealed that the placement of bee
colonies had impact on fruit yield. The fruit set to the tune of 86.4 per cent was recorded
in an orchard where additional bee colonies were placed in comparison to 66.39 % in an
orchard where no additional bee colonies were kept. Therefore, keeping honeybees
resulted in better fruit set and thus higher yield. In these pockets of the state citrus is
considered to be the major nectar yielding source for honeybees (Anonymous 2009).
Studies were made at Lyallpur, Pakistan to determine the effect of insect pollinators,
mostly Apis dorsata and A. florea , on the fruit set and matured, and on the physical and
chemical properties of Kinnow mandarin ( Citrus reticulata). Significantly more fruit set
and matured on branches accessible to insect pollinators than were insects were
repelled or excluded. Effects of fruit size, juice content and the number of seeds were
also significant, but not acidity, or sugar and total soluble solids (Haq et al. 1978).
117
Pomegranate, Punica granatum
The presence of both male (unfertile) and bisexual (fertile) flowers on the pomegranate allow it to be self-pollinated as well as cross-pollinated. Several studies have shown
that cross-pollination results in around about 20% increase in fruit set as well as an
increase in overall fruit quality (Derin and Eti, 2001). Because of its pollen heaviness,
there is very little wind dispersal of the pollen and thus insects are mostly responsible
for the transport of pollen between flowers. There is little quantitative data available with
regard to the efficiency of honey bees in the pollination of pomegranate; however, McGregor
(1976) states that growers in California arrange for honey bee colonies to be placed in or
near their fields, believing that their presence benefits pomegranate fruit production.
Derin and Eti (2001) describe the honey bee as the principal pollinator of pomegranate.
In addition, the Department of Agriculture and Food in Western Australia (2005) also
suggest that 10% of pollination in pomegranate can be attributed to honey bees.
Whilst the evidence suggests that insect pollinators including honey bees are of
significant benefit in increasing the fruit set and quality of pomegranate yields, studies
have shown that sizeable yields can still be obtained from self-pollination. For example
when flowers are bagged to exclude insects and cross-pollination, fruit sets of up to
45% can still be obtained (McGregor 1976). With subsequent cross-pollination, however, fruit set can increase to around 68% and additionally there is an increase in fruit
quality (i.e. number of seeds per fruit, fruit size).
Arid/semi arid fruit crops
Aonla, Emblica officinalis syn. Phyllanthus emblica
Aonla is basically a cross pollinated plant. Wind, honeybees and gravity play an
important role in effective pollination. In a systematic study, at the Central Institute of
Subtropical Horticulture (CISH), Lucknow, Melipona trigona spp. (PRA 47.5%) Apis florea
(PRA 21.0%) and Coccinelid beetles (PRA 11.0 %) were observed. A. cerana indica
(PRA 5%) and others (PRA 14.50 %) were, respectively, at CISH, Lucknow (Anonymous,
2002).
In the survey of aonla orchards at Narendra Dev University of Agriculture and
Technology (NDUAT), Faizabad, PRA of different pollinators, viz., Melipona spp., A. florea,
A. cerana indica were 60.32, 17.41, 3.81 per cent, respectively, and two species of
calliphorid flies and one species of beetles was 18.46 per cent. The pollinators visitation
order was Melipona trigona spp. > A. florea > Coccinelid beetles > A. cerana indica .
Earlier workers reported that there was no self incompatibility in aonla and cause of
poor fruit set may be due to high percentage of male flowers (Bajpai 1968; Ram 1971).
However, pollination studies showed considerable variation with respect to fruit set and
retention (Pathak and Srivastava 1994). Open pollination showed the maximum fruit set
(42.5%) followed by geitonogamy (29.4%) and bagging (4.6%). Similarly, fruit retention
to the tune of 8.9, 3.0 and 0.5 per cent was observed in open pollination, geitonogamy
and bagging, respectively. Fruit retention in cross-pollination of Chakaiya x Francis,
118
Chakaiya x NA-7; Banarasi x Kanchan; Banarasi x NA-7 and Kanchan x NA-6 were
16.8, 15.6, 18.6, 18.5 and 14.9 per cent, respectively. Two seasons' pooled data indicated that self-pollination under bagging resulted in the lowest fruit set (2.35%) with no
fruit retention at maturity.
Mohammad and Ram (1990) and Singh et al . (1998) observed absolutely no fruit set
under bagging. Significantly, the highest fruit set (61.43%) and retention (18.54%) were
recorded under open pollination. In accordance of this Balasubramaniam and Arulmozhiyan
(2003) reported that 4 cultivars of aonla expressed poor fruit set and retention in bagging
and improvement was observed with geitonogamy and sibbing. All cultivars resulted
favourably for open pollination with respect to fruit set and retentivity (46.74 and 29.16%).
The study confirmed the selfincompatibility in aonla. The pollination stimulus from pollen of other cultivars was higher in open pollination. Among different cross combinations, the highest fruit set (58.42%) and retention (10.41%) were recorded in NA-7 x NA6 combination closely followed by NA-6 x Krishna (46.86 and 9.83%, respectively). The
poorest fruit set under bagging confirmed the problem of self-incompatibility in NA-7.
Singh et al. (1998) also reported that most of the aonla cultivars were self-incompatible and need provision of pollinizer in order to improve fruit set and retention. Higher fruit
set and retention under open and cross-pollination may be because of compatible mating and higher pollination stimulus provided by the pollen taking part in pollination and
fertilization (Singh et al. 2001). In order to obtain higher fruit set and retention, NA-6 and
Krishna were found to be suitable pollinizer for the leading aonla NA-7. Krishna as pollinizer
was also found to improve the fruit quality of NA-7 with respect to fruit size, total soluble
solids (TSS) and vitamin-C content.
Ber, Ziziphus jujube
The flowers are protandrous. Hence, fruit set depends on cross-pollination by
insects attracted by the fragrance and nectar. Pollen of the Indian jujube is thick
and heavy. It is not airborne but is transferred from flower to flower by honeybees. The
flowers are pollinated by ants and other insects, and in the wild state the trees do not
set fruits by self-pollination. Ber propagates by seeds, seedlings, direct sowing, root
suckers as well as by cuttings.
Singh (1984) recorded that honeybees and other hymenopteran insects on jujube
( Zizyphus mauritiana L.amk.) were more active on upper branches while housefly and
other dipteran insects were abundant on middle and lower branches.
Kumar (1990) reported in 'ber' that among different insect visitors, Apis spp. were
observed foraging on both nectar and pollen while dipteran and lepidopteran insects
foraged for nectar only. Among Apis spp., A.dorsata and A.mellifera took long distance
flights while A. florea made short distance flights usually on the same branch for floral
rewards. All the insect visitors were top workers except Camponotus sp. and lepidopteran
insects which were side workers (nectar robbers).
Apis florea , Ceratina spp., Trigona spp., Sarcophaga spp. were recorded as the
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major pollinators of Z. mauritiana (Rama Dev et al ., 1989 and Barker et al ., 1971).
Kumar (1990) also reported that A. florea was the most efficient pollinator of 'ber' flowers
followed by A. mellifera and A. dorsata under Hisar conditions.
Similarly in ber, per cent fruit set under natural conditions was highest in Banarsi
Pewandi (17.15%) followed by Thornless (7.41%) and Banarsi Karaka (5.54%) as
reported by Teaotia and Chauhan (1964). Similar observations of self-incompatibility in
var. Banarsi Karaka was reported by Gill (1970). Kumar (1990) also reported that the
average per cent fruit set in 'ber' in self and open pollinated flowers, irrespective of
cultivars were 4.67 and 15.36, respectively. The per cent fruit set under open pollination
was higher in all the cultivars than the self pollination. Cultivars Umran and Mudia Murhara
were self-compatible while Banarsi Karaka was highly self-compatible.
Phalsa, Grewia subinaequalis syn. G. asiatica
Flowering in phalsa started in March and continued upto middle of May (Randhawa
and Dass, 1962; Nehra et al. , 1986; Pareek and Panwar, 1981). While Nehra et al .
(1985) reported that the flowering period of Tall was short as compared to Dwarf type of
phalsa, but flowering started early in latter.
Megachile spp., Anthophora spp. Sphecodes spp., Eristalis spp. and Muscoid fly
were the insect visitors on phalsa flowers. Maximum activity of these insects was seen
in between 8.00 AM to 12.00 Noon during April-May. Studies pertaining to fruit set under
self and open pollination are an important aspect to ascertain yield potential of a crop.
Fruit set percentage varies from variety to variety and place to place. Per cent fruit set
in phalsa under self and open pollination was 26.5 and 64.9, respectively, (Randhawa
and Dass, 1962).
Parmar (1976) reported that insects visiting phalsa flowers belong to various groups
including honeybees, hoverflies, Polistes spp., Lycaenids and Camponotus spp. (Parmar,
1976). Of all the insect visitors, the honey bees played the major role, insects have been
visitings the flowers all day round but their maximum activity was observed between
9.00 AM to 12.00 Noon which coincided the time of anthesis and dehiscence of anthers.
He further reported 71.6 per cent fruit set in open pollination and 51.1 per cent in self
pollination in phalsa.
Among different insect pollinators, Apis florea, A. mellifera, A. dorsata, Megachile
bicolor and Chalicodoma cephalotes were observed foraging both nectar and pollen,
while other foraged for nectar only. Irrespective of modes of pollination, there were nonsignificant differences in fruit set in tall (45.00%) and dwarf (38.01%) types of phalsa.
(Gill et al. , 2001a).
On the basis of pollination index, A. florea was found to be the most efficient
pollinator (22989.2) of this crop followed by A. dorsata and A. mellifera with a pollination
index of 18634.0 and 2286.0, respectively (Gill et al. , 2001b).
120
Suggested Readings
Anonymous, 2011a. Annual report of AICRP on honey bees and pollinators. PC Unit,
CCS HAU Hisar.
Balasubramaniam, S. and Arulmozhiyan, R. 2003. Open pollination - A method for higher
production in aonla ( Emblica officinalis Gaertn) under rainfed vertisol. Paper
presented in Nat. Seminar on Production and Utilization of Aonla, organized by
All India Aonla Grower.s Association, Salem, Tamil Nadu, India.
Dhankar, N. K., Kaushk H. D., Sharma S. K. and Arora R. K. 1999. Hi-tech citrus
management : Proceedings of International Symposium on Citriculture ,
(Eds.Singh, S. and Ghosh S.P.) November 23-27, 1999, held at NRC for Citrus,
Nagpur, Maharashtra. pp. 945-949.
Gill, S. S., Kaushik, H. D. and Sharma, S. K. 2001b. Pollination efficiency of three Apis
spp. foraging on Phalsa (Grewia subinaequalis D.C.). Annals of Entomology.
19 (1) : 19-21.
Kumar, S.1990. Studies on insect pollination in 'ber', Zizyphus mauritiana Lamk. M.Sc.
Thesis. Haryana Agricultural University, Hisar.
Mishra, P. K. and Yazdani. 1997.Population dynamics of forager honey bees on litchi.
Litchi chinesis (Gaertn)Sonn., blooms in north Bihar. Indian Bee J. , 59 (3) :
154-157.
Mohammad, A and S. Ram. 1999. Cause of low fruit set and heavy fruit drop in Indian
gooseberry (Emblica officinalis Gaertn). Indian J. Hort. 47 (3) : 210-77.
Rama Devi, K. Atluri, J. B. and Reddi, Subba, C. 1989. Pollination ecology of ecology of
Ziziphus mauritiana Lamk. (Rhamnaceae). Proc. Indian Acad.Sci. (Plan Sci.)
99 (3) : 233-239.
Sehgal, O. P. 1961. Studies on morphology and blossom biology in guava (Psidium
guajava L.) M.Sc. Thesis. IARI, New Delhi.
Singh, M. P. 1984. Studies on the activity of some insect pollinators on jujube ( Zizyphus
mauritiana Lamk). Entomon 9 (3) : 177-180.
Walsh, K. B., Guthrie, J. N. and White, D. T. 2006. Control of phytoplasma diseases of
papaya in Australia using netting. Australasian Plant Pathology , 35 : 49-54.
Teaotia, S. S. and Chauhan, R. S. 1964. Flowering, pollination, fruit set and fruit drop
studies in ber ( Zizyphus mauritiana Lamk). Indian J. Hort . 21 : 40-50.
121
EFFECTS OF CLIMATE CHANGE ON POLLINATOR POPULATIONS
V. V. Belavadi
Department of Entomology,
University of Agricultural Sciences, Bangalore 560 065
In India, nearly 700 million rural populations directly depend on agriculture, forests
and fisheries (all climate-sensitive sectors) and natural resources (water and biodiversity)
for their subsistence and livelihoods. Unfortunately, India is also among the countries
most threatened by climate change with experts warning that rising temperatures will
lead to more floods, heat waves, storms, rising sea levels and unpredictable farm yields.
Studies show that surface air temperatures in India are going up at the rate of 0.4 o C
every 100 years, particularly during the post-monsoon and winter seasons (Ravindranath
and Sathaye, 2002).
Kumar and Parikh (2001a and 2001b) examined the impact of climate change on
agricultural crop yields, GDP and welfare. They have estimated a range of equalibrium
climate change scenarios and project a temperature rise of 2.5oC to 4.9 oC for India, and
have shown that even with farm-level adaptations, the impacts of climate change on
Indian agriculture would remain significant. They estimated that with a temperature change
of +2 oC and an accompanying precipitation change of +7%, farm level total net-revenue
would fall by 9%, whereas with a temperature increase of +3.5 oC and precipitation change
of +15%, the fall in farm level total net-revenue would be nearly 25 per cent.
Studies conducted at IARI indicate greater losses in the Rabi crops and that with
every 1 oC rise in temperature there will be a reduction in wheat production by 4-5 million
tonnes. (NIDO, 2009). Based on future climate projections of Regional Climate Model of
the Hadley Centre (HadRM3) using A2 and B2 scenarios and the BIOME4 vegetation
response model, Ravindranath et al. , (2006) have shown that 77% and 68% of the forest
areas in the country are likely to experience shift in forest types, respectively, under the
two scenarios, by the end of the century, with consequent changes in forests produce
and, in turn, livelihoods based on those products. Correspondingly, the associated
biodiversity is likely to be adversely impacted.
Hansen and Lebedeff (1988) predicted that global mean temperature in 2005 will be
14.45oC while the observed value was 14.50 oC (Srinivasan, 2006), which means the models about the increase in global temperature are close to reality. One of the effects of
global warming on the plant community that was recognized was on the flowering phenology. Global climate change could significantly alter plant phenology because temperature influences the timing of development, both alone and through interactions with
other cues, such as photoperiod (Partanen et al., 1998).
Pollination is an important ecosystem service considered as a regulating service by
the Millennium Ecosystem Assessment. It is fundamental to the reproduction of flowering plants and is essential for the production of about one-third of the food consumed by
humans (Klein et al., 2007). Pollination is often taken for granted and is commonly
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thought of as a free service. Of the 352,000 species of flowering plants in the world
(Paton et al., 2008) about 87.5 per cent (i.e. 306,000 species) depend on animals,
mostly insects, for pollination. Nearly 75 per cent of the world's food plants show
increased fruit or seed set with insect visitation (Klein et al., 2007). The economic value
of this benefit is estimated to be about $ 153 Billion per year (Gallai et al., 2009).
Pollinators are considered key-stone species in many situations not only because they
support humanity but also maintain diversity in an ecosystem. There is mounting evidence of a global decline in pollinators that threatens the reproductive cycle of many
plants and may reduce the quality and quantity of fruit and seeds, many of which are of
nutritional and medicinal importance to humans. Such evidence includes the finding that
those plant species that depend on pollinators which are declining have, themselves,
declined relative to other plant species indicating a causal connection between local
extinctions of functionally linked plant and pollinator species (Biesmeijer et al., 2006).
A growing number of studies suggest that climate change may be one of the biggest
disturbance factors imposed on ecosystems today (Walther et al., 2002; Parmesan
2006). Observational evidence from many continents has indicated that many ecosystems are affected by regional and global climate changes, particularly temperature
increases. Because of the cumulative evidence of a close relationship between greenhouse gas emissions, through human use of fossil carbon, and global change (IPCC,
2007), there has been a surge of scientific interest in the ecological and evolutionary
effects of climate warming. Studies have shown that both the distribution and phenology
of many plants and animals are biased in the directions predicted from global warming in
the last few decades (Parmesan, 2006).
For species involved in pollination interactions, this is evident through recent changes
in flowering phenology (Fitter and Fitter, 2002; Miller-Rushing et al., 2007) and the firstappearance dates of butterflies and migrating birds (Roy and Sparks, 2000; Gordo and
Sanz, 2005, 2006). Whether climate warming will affect ecosystem functioning depends
on how interactions among species are influenced. Several studies have shown alterations in trophic relationships and energy-flows in both predator-prey and plant-herbivore interactions as a consequence of rising temperatures (Visser and Both, 2005).
We should be concerned about climate change in India, since this phenomenon
might have substantial adverse impacts on flowering phenology of cultivated crops, their
pollinators and in short on the productivity of such crops. The impact on agriculture
would be unimaginably high through the effects of climate change on pollinator populations. However, the information available on pollinator decline due to climate change
and the consequent effect on agricultural production in India is very scanty.
Phenological networks rely on volunteers to collect observations of various
phenophases of wild plants, fruit trees and agricultural crops at numerous stations. The
longest and best known phenological records come from the Far East and Europe,
including a 5000-year record of phenological events, weather and farming activities in
China (Chen, 2003), the 1300+-year Kyoto cherry blossom time series (Menzel and
Dose, 2005), 670+ years of grape harvest dates in Central Europe (Chuine et al., 2004),
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and the 200+ lyear Marsham record of plant and avian phenology in the UK (Sparks and
Carey, 1995). More recently, shifting phenology from the mid-20th century onwards is
evident from numerous phenological observation networks in the Far East (Matsumoto
et al., 2003), North America (Schwartz and Reiter, 2000) and Europe (Menzel et al.,
2006). A meta-database (http://www.pik-potsdam.de/rachimow/epn/html/ frameok.html)
of existing networks shows that most observation networks are located in temperate
ecosystems and that long-term phenological observations in the tropics are lacking.
The timing of pollination is determined by climatic cues such as temperature and
water availability (Cleland et al., 2007). Many pollinators also synchronise their life cycles
with climatic cues, and this phenological response of plants and pollinators needs to
remain broadly synchronised for many plant-pollinator relationships to remain viable.
Climate change is altering the phenological response of plants and some pollinators
may be unable to alter their life cycles in synchronisation with altered pollination timing.
Kudo et al. , (2004) show that, since 1998, plants have been flowering much earlier in
alpine environments whilst the time of emergence of pollinators has not necessarily
changed, thereby disrupting pollination. Climate change also shifts the latitudinal and
altitudinal climate 'envelope' of species. Some species are more mobile or adaptable to
change and so the composition of plant and pollinator assemblages is likely to change
in many locations. For example, species in the tropics appear to be living at or near
their thermal optimum and further warming may cause some species to migrate to cooler
areas or die out (Deutsch et al., 2008).
Any decline in pollination services could lead to cascading effects on ecosystems
and an overall loss of biodiversity and ecosystem services (such as agricultural production). Mutualistic relationships are most directly affected since the loss of individual
pollinator species will lead to the extinction of any co-dependent plant species (and
vice-versa). A study conducted under the European project Assessing Large-scale environmental Risks for biodiversity with tested Method (ALARM), has shown that specialist
pollinators and the obligate out crossed plants that they pollinate decline in tandem
(Biesmeijer et al., 2006).
Ecosystems possess some robustness to the loss of individual species since multiple pollinators can pollinate most plants, each with somewhat different effectiveness or
responses to environmental change. However, the loss of particular pollinator species
and the impoverishment of pollinator diversity diminish the resilience of ecosystems to
change, which are subsequently less able to provide services to humans (FAO, 2008a).
Many pollinators are also important food sources for higher animals, so their loss may
threaten birds, bats and other small mammals. As individual species are lost from an
ecosystem, the functional redundancy that diverse ecosystems generally display is reduced and resilience to change also tends to decline.
Though there have been extensive studies on effects of climate change on agricultural crops, none, whatsoever, have concentrated on the effects on pollinator populations and the consequent reduction in agricultural productivity in India except for a few
anecdotal references on the shifts in apple cultivation to higher altitudes in the Himachal
124
Pradesh. Historical data on flowering phenology is available for many countries for
various crops but in India we may get this kind of information only for coffee and a few
spice crops, to help us compare with the past weather parameters.
Suggested Readings
Biesmeijer, Roberts S. P. M., Reemer M., Ohlemüller R., Edwards M., Peeters T.,
Schaffers A. P., Potts S. G., Kleukers R., Thomas C. D., Settele J., Kunin W. E.,
2006. Parallel Declines in Pollinators and Insect-Pollinated Plants in Britain and
the Netherlands. Science 313 : 351-354.
FAO, 2008a. Rapid Assessment of Pollinators' Status. FAO, Rome, Italy.
Gordo, O. and Sanz, J. J. 2006. Temporal trends in phenology of the honey bee Apis
mellifera (L.) and the small white Pieris rapae (L.) in the Iberian peninsula (19522004). Ecol. Entomol 31 : 261-268.
Klein A. M., Vaissière B., Cane J. H., Steffan-Dewenter I., Cunningham S. A., Kremen
C., Tscharntke T., 2007. Importance of pollinators in changing landscapes for
world crops, Proceedings of the Royal Society B , 274 : 303-313.
Parmesan, C. 2006. Ecological and evolutionary responses to recent climate change.
Annu. Rev. Ecol. Evol. Syst . 37 : 637-669.
Ravindranath, N. H., Joshi, N. V., Sukumar, R. and Saxena, A., 2006. Impact of climate
change on forests in India. Current Science 90 : 354-361.
Ravindranath, N. H. and Sathaye, J. A., 2002. Climate Change and Developing Countries
(Advances in Global Change Research), Kluwer Academic Publishers, Dordrecht.
Roy, D. B. and Sparks, T. H. 2000. Phenology of British butterflies and climate change.
Global Change Biol. 6 : 407-416.
Schwartz, M. D. and Reiter, B. E. 2000. Changes in North American spring. Int. J.
Climatol. 20 : 929-932.
Sparks, T. H. and Carey, P. D. 1995. The responses of species to climate over two
centuries: an analysis of the Marsham phenological record, 1736-1947. J. Ecol.
83 : 321-329.
Srinivasan, J., 2006. Hottest decade: Early warning or false alarm? Current Science
90 : 273-274.
Visser, M. E. and Both, C. 2005. Shifts in phenology due to global climate change : the
need for a yardstick. Proc. R. Soc. B-Biol. Sci. 272 : 2561-2569.
Walther, G. R., Post, E., Convey, P., Menzel, A., Parmesan, C., Beebee, T. J. C. 2002.
Ecological responses to recent climate change. Nature 416 : 389-395.
125
ABIOTIC ENVIRONMENTAL FACTORS AFFECTING BEES ACTIVITY
V. S. Malik
Department of Entomology
CCS Haryana Agricultural University, Hisar 125 004
Honey bee activities are being carried out by farmers in rural areas as an integrated
farming programme which provides income to the rural people. Pollinators are essential
for orchard and forage production as well as for the production of seeds of many roots
and fibre crops. Pollinator's decline is likely to impact the production and costs of
vitamin rich crops like fruits and vegetables leading to increasing unbalanced diet and
health problems. The optimum population of pollinators for effective pollination is also
influenced by abiotic environmental factors such as temperature, relative humidity, wind
velocity and sunshine etc. Among the various pollinators, honey bees are considered to
be the most efficient and major pollinators. Hence, efforts have been made to study the
impact of various abiotic factors on bees activities.
i)
Temperature
The honey bee colony has a remarkable feature which enables it to survive in the
adverse climate is its ability to regulate temperature. It survives regardless of outside
temperature, provided food (honey) is available. In the brood area, the temperature is
maintained between 33 oC and 35oC. For this reason, the larval development proceeds at
a predictable rate. In summer, the area is cooled by fanning and water evaporation.
When the surrounding air temperature drops to 14oC, the bees form a cluster. The tightness of the cluster regulates the temperature with bees acting as generators and insulators. While the colony can survive adverse conditions, whereas individual bees are quite
helpless in dealing with climate. They can not fly when their body temperature drops
below 10 oC, lose the power to move at 5 oC and freeze at -1.9 oC. In order to survive, the
honey bee cluster temperature can not drop below 7oC. The winter broodless cluster
temperature ranges between 20oC and 36 oC with the normal about 29oC. In summer, both
the species ( Apis cerana indica and A. mellifera ) significantly lowered their hive
temperature when the outside air temperature exceeded 40oC, A. cerana colonies
absconded frequently whereas no such tendency was observed in A. mellifera . At
temperature above 40 oC, the fanning was more regular and frequent in A. mellifera than
A. cerana which was evident from the rate of evaporation (Verma, 1970). Both in fall and
spring, A. cerana started foraging activities at 0700 hrs., but A. mellifera began at 0900
hrs. when the outside temperature was much higher.
The cluster temperature of A. cerana hive was significantly higher than that of A.
mellifera possibly due to difference in compactness of cluster and the colony strength
(Verma, 1970). Results on high and low lethal temperature suggest that A. mellifera
survived high lethal temperature (50 oC) than A. cerana. The survival time at 5 oC showed
no difference between the species (Verma and Edward, 1972).
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During winter, worker bees raise brood nest temperature by their thoracic muscular
movements. The temperature is conserved by making a cluster of many layers. The
bees in different layers keep on changing their positions to avoid chilling of bees in the
outer most of the cluster.
ii) Relative humidity
Humidity also plays an important role both during summer and winter months when
it helps in the regulation of bee colony temperature. Jessup (1924) calculated indirectly
that in the brood chamber, humidity varied 20-80% at 35 o C, while Dertel (1949)
determined that in summer the relative humidity ranged between 40-62% in brood
chamber and upto 78% in the supers. Anderson (1948) reported that humidity in a colony
during winter was usually above 55 % and also higher than in the atmospheric air. Contrary to the widely fluctuating humidity values in the hive, the relative humidity in the
brood-nest is reported to be fairly constant within the narrow range of 35-45%
(Budel and Harold, 1960). These limited data suggest that, unlike temperature, the hive
humidity, in general, is not subjected to careful adjustment since the adult bees are
capable of surviving in a wide range of humidity (Woodrow, 1935).
Scanty informations are available about the effect of humidity on the flight/foraging
range of honey bees except that in spring high relative humidity decreased pollen collection (Rashad, 1957). However, it has been revealed that A. cerana workers bring in abundant maize pollen during the monsoon months when the air is almost saturated with
moisture in the hills. This clearly indicates that further research on relationship of humidity with honey bees is needed.
Water is required for diluting honey as larval food, for cooling and humidifying the
hive interior and adult bees also need water to maintain their body temperature while in
flight (Woodrow, 1941). Water requirement of a colony also depends upon strength and
stage of the brood in the hive. This need is especially acute when foragers can not fly
because of cold and rainy weather. For average colony during spring season daily
requirement is approximately 150 g while for strong colony under hot and dry conditions
daily requirement is about 1 kg.
Relative humidity, on its own, is not an important factor in bee activity. However, the
combination of temperature and humidity is most important in the ripening of the anthers
of the flowers and the availability of pollen to visiting insects. Optimum conditions
for pollen release are temperature of 20°C and above relative humidity of 70% or less.
Therefore, low temperatures and high humidity have the double effect of reducing bee
activity and slowing the release of pollen.
iii) Sunshine/Solar radiation
Atmospheric temperature as well as the intensity of light has greatly been
influenced by sunshine. Both these factors play an important role in the flying/foraging
activities of the honey bees. Brittain et al. , (1933) have stated that within the temperature range of bee activity, light apparently had more important influence on bee flight
127
than slight changes in temperature as they observed a. general upward trend in bee
activity with increasing light values. Similar results have been reported by Butler and
Finney (1942), who found that within any single day there was an average increase of
10-20% in the number of bees leaving the hive when the radiation rate increased by 0.1
cal./cm/min. According to Karmo (1961) the temperature threshold for foraging activity
is less at the beginning than at the end of the day but foraging ceases when conditions
are better than those in which it was initiated. Since temperatures are usually higher at
dusk than at dawn, it may be inferred that cessation of foraging is influenced by
light intensity rather than by temperatures. However, there is paucity of data on the
relationship of bee activity and sunshine and more concerted efforts are needed to draw
definitive or acceptable conclusions.
Flight activity is reduced during periods of heavy cloud cover. When the cloud cover
is seven-tenths or more, bees begin to lose interest in foraging. These weather factors
are important as most fruit trees in Victoria, especially in the south, flower during early
spring when conditions for bee flights may be poor. Cool, dull, showery conditions will
limit bee kflights up to about 150 metres from the hive. Colonies of bees should therefore
be located within the orchard to obtain best pollination. They should be evenly distributed over the whole area so that all trees are within 100-150 metres of a colony.
iv) Wind Velocity
High winds tend to slow the flight speed of bees, hence reduce the number of flight
per day. Wind essentially influences the outdoor activities of the bees but there are not
enough data correlating its effects on honey bee flights. However, their own flight speed
of about 22.5 km/hr gives an indication that flying activities of bees is likely to be greatly
inconvenienced by winds. Brittain (1933) studied bee counts on apple blossoms at
varying wind velocities and observed a maximum number at a wind velocity of 1 mile (1.6
km) and a steady fall to one-seventh of this number as the speed increased to 7 miles
(11 km)/hr. He concluded that even very low winds had a decided influence on foraging
activity. Rashad (1957) found that at wind velocities above 17.7 km/hr the pollen gathering activity slackens while it ceases altogether at 33.8 km/hr. According to Gary (1976)
bees do not work long during wind blowing much above 24 km/hr. It is generally stated
that a wind velocity of 40 Km/hr will stop bee flights altogether though on occasions they
may fly during 64 km/hr wind speed.
Apart from workers, the flights of queen and drones are also influenced directly by
wind. Gary (1976) stated that low wind velocities are essential for drone flights though
queen can undertake mating flights at relatively higher wind speeds. He further reported
that the number of matings is greatly reduced at wind velocities of 19.3 to 27.4 km/hr
and no matings were observed at 27.4 to 37.0 km/hr.
v) Rain
Flight activity of honey bees ceases during rain. In periods of inclement weather
bees may fly between showers for short distances of up to 150 metres. Moderate to
heavy rains inhibit bee flights and foraging not only because they cause reduction in
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atmospheric temperature and light intensity, besides increasing humidity but also
because the bees themselves are subjected to the risk of wetting, drenching or even
actual drowning. In addition, wet blossoms, after rains are difficult for bees to work
upon. Nonetheless, they have been reported to fly short distances in light rain to some
nectariferous plants like rhododendrons.
vi) Snow
Snow and snow icicles have indirect effect on honey bees by lowering down the hive
temperature and sometime bees metabolic rate is totally reduced. Snow should not
cover the hives completely so that their ventilation is blocked. The hive entrance should
be cleared and icicles if any should be removed at the entrance.
vii) Thunder storms
Thunder storms elected cessation of foragers at feeders site 6 km away from the
hive but at 100m distance continuous until rain began (Boch, 1956).
viii) Environmental influence on plants as related to honey bees
Plant food (nectar/pollen) is a limiting factor in the survival, abundance and distribution of honey bees. Since the physical environment has a decided influence on plants,
and thus on the availability of nectar/pollen to honey bees.
Long term honey records indicate a direct association between honey plants and
weather (Kenoyer, 1916; Jorgensen and Markham, 1953). A close association has been
found between the amount of sunshine in a period of about 24 hours prior to collection of
nectar and nectar yields in Trifolium spp. and sainfoin, Onobrychis viciaefolia (Shuel,
1952 and 1959). In temperate regions, photosynthesis affecting nectar secretion is more
likely to be restricted by low light intensity than by low temperature (Thomas & Hill,
1949) but the combination of low night and high day temperatures has been considered
to promote good nectar flows.
Excessively high temperature in combination with meagre rainfall can lower nectar
secretion by causing moisture stress in the plant (Shuel and Shivas, 1953). This happens when the rate of water loss from the shoots exceeds the water uptake from the
roots. This suggests that a judicious level of soil moisture provided by adequate rainfall
is not only required for abundant nectar flows but also for balanced plant growth since
both nectar secretion and number of flowers may be reduced in dry soil (Czarnowski,
1953). However, excessive rains during flowering may wash much of the nectar or dilute
it in flowers to make it unprofitable for bees.
Atmospheric humidity affects the sugar contents of the nectar in many flowers, hence,
greatly affects the number of bees visiting them. Mainly on account of humid conditions,
some sources are worked early in the day and others later but sunshine and temperature also are important factors. A source of over concentrated nectar (e.g. lime) may
become attractive to bees with the increase in humidity as concentrated sugar solutions
are decidedly hygroscopic.
129
While analyzing the impact of the physical factors of the environment, it has been
observed that these factors greatly affect both the life as well as the routine activities of
honey bees derectly. They also indirectly influencing through pollen production and nectar secretion. The thorough knowledge of the behavioural responses in relations to environmental stimuli, is pre-requisite for the economic exploitation e.g. both for honey production and pollination of honey bees in the prevailing scenario. The scanty information
on this aspect further reveals that a comprehensive and systematic research work needs
to be carried out on this aspect.
Suggested Readings
Gary, N. E. 1976. Activities and behaviour of honey bees. In : The Hive and the Honey
Bee. Dadant and Sons (eds.) : 185-264. Dadant and Sons, Hamilton.
Seeley, T. D. 1984. Honey Bee Ecology , Princeton University Press, Princeton, New
Jersey, USA.
Verma, L. R. 1970. A comparative study of temperature regulation in Apis mellifera L.
and Apis cerana F. Amer. Bee J. 110 (10) : 390-391.
130
QUEEN BEE REARING TECHNIQUES FOR
COMMERCIAL BEEKEEPING
Jaspal Singh
Department of Entomology,
Punjab Agricultural University, Ludhiana 141 004
Performance of the honey bee colonies depends on the traits like longevity, industriousness, disease resistance, temperament, swarming, absconding and other behavioural
attributes inherited from its queen. Thus, for obtaining success in beekeeping and thereby
earning higher profit from this enterprise, young freshly mated and quality queen bees are
required because a young vigorous queen generally is more prolific.
Perquisites For Queen Rearing Methods
Some of important pre-requisite operations required for all the methods of mass
queen rearing such as management of breeder colony, starter colony and cell builder or
finisher colony are discussed below.
a ) Breeder colony : Specific comb arrangement in the breeder colony is required to
get larvae required for grafting from selected colony. The breeder colony is divided
into two compartments by inserting a vertical queen excluder in such a way that one
part contained six combs and another contains three combs. The mother queen bee
is confined to the three-frame compartment of breeder colony. After 3 days of deposition of eggs in the empty dark comb it is full of newly hatched larvae for grafting in
the queen cell cups. Each time while removing the larvae, another empty comb is
replaced for egg laying. After emergence of adult bees, that comb is replaced with
another sealed brood comb to ensure the proper strength of nurse bees in the colony.
b) Queen cell Starter colony : This usually is a strong queenless colony with enough
honey, pollen and large number of nurse bees. This can also be prepared by uniting
two queenless colonies with the provision of emerging brood comb.
c) Cell builder or Finisher colony : Cell builder colony is established 4 days prior to
larval grafting by dequeening a 10 or more frame strong colony. The dequeened colony
will raise a few queen cells from which the royal jelly to prime the artificial queen cell
cups is extracted by discarding the royal larvae. Extra young bees or sealed brood
frames are given to the colony to maintain a sufficient number of nurse bees. The
comb arrangement in the cell builder colony is kept as given below :
HSSEYCPESH
Where H = Honey comb
S
= Sealed comb
E
= Emerging brood comb
Y
= Young larval brood comb
C = Frame with queen cell cups/ grafted larvae,
P
= Pollen comb.
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Cell finisher colony can also be a strong double chamber queen right colony in which
the queen is confined to the lower chamber by using a horizontal queen excluder and
queen rearing frame is placed in the queenless super having the arrangement of bee
frames as described for queenless cell builder colony.
Methods For Commercial Queen Rearing
There are several methods of mass queen rearing, which are briefly described below:
1.
Miller method : In this method comb foundation cut into deep v-shaped sections
and reaching about two third way down the frame is used/ fixed. From such frames
the wires except the upper one, should be removed before hand. The frame is then
inserted into the middle of brood nest of the selected strong queen-right colony. By
feeding the colony with sugar syrup the colony is induced to raise comb cells on
V-shaped comb foundation sheet and reposition big the queen in the raised comb
cells. When this has been achieved this frame with egg comb is removed from the
mother colony and is inserted in the centre of the cell builder colony between larvae
brood and pollen comb. Cell builder colony should be very strong and be dequeened
at least 24 hours before inserting the prepared comb frame containing eggs in worker
cells. All the other containing eggs combs and young larvae should also be removed
from the cell builder colony. The bees will build queen cells along the border of the
given V-cut comb and after about 10 days sealed queen cells would be ready for
transplanting in the desirous dequeened colonies. With this method even upto thirty
queen cells are frequently produced on each comb under favourable conditions.
2. Alley method : The breeder queen is induced to lay eggs in the newly drawn comb.
After 3 days of laying, the eggs will hatch, the comb is then taken to room with
controlled temperature (34-35°C) and the comb is cut into strips of one cell wide row.
The cell walls of the comb containing the larvae are shaved down to about 6 mm from
the cell base. The next step is to destroy two out of every three adjacent larvae (by
rotating a match stick in the cells) in the row so as to provide sufficient space
between the two royal cells. The prepared one cell hide strip of comb, containing
young larvae, is then glued to the lower edge of a comb already trimmed in a semicircle. This frame is then given to the cell builder colony prepared as mention in
Miller methods. The workers will remodel the cell containing newly hatched larvae
and rear them into queen cells.
3. Smith method : This method is a modification of the Alley method in which the
stripes of cells containing eggs or very young larvae (1 to 2 days old) are glued by
bees wax to the horizontal wooden bars of the queen rearing frame and then the bars
are fitted into frames parallel to the top bars. Such frames are then placed in the cell
builder colonies.
4. Hopkin method : A fresh comb is placed in the brood nest of mother colony until it
is filled up with eggs. Then it is removed and brought into a warm room (34-35°C) and
placed flat on a table. Three out of every four rows of cells across the comb are
destroyed up to the mid rib, leaving every fourth row intact. Two out of three eggs are
132
destroyed in each row. This frame is then laid over the top bars of the frames in the
brood chamber of cell builder colony with the prepared side facing downward. In
order to provide space for bees to raise the queen cell properly, one empty wooden
frame, without wires, is placed just beneath the laid over comb. The bees will start
raising the queen cells. When the raised queen cells are sealed they are cut out
with the sharp warm knife and grafted into the dequeened colonies.
5. Doolittle or Grafting method : In this method the artificial queen cell cups are
used. These cups are first primed with royal jelly and then selected larvae of the
desired age (<24 h) are grafted into them. This method involves the following steps :
i)
Making the queen cell cups : For making queen cell cups, light coloured pure
bees wax and cell cup forming stick (made of wood with the tip moulded to the
shape/ size (9-10 mm diameter) of the average queen cell) are required. The
bees wax should be melted in a water bath and held at temperature just above
the melting point. Dip the forming stick into a weak solution of honey in water.
Shake off the excess liquid and then dip the stick into the molten wax to a
depth of 8-9 mm for a while. Then withdraw it and hold in air until the wax
solidifies. Repeat the process five to six times. Every successive dip in the
molten wax should be made 1 mm lesser then the previous one so as to obtain
a cup with a good base and tapering thin walls.
ii)
Affixing cell cups : The next step in the process is to attach the cell cups to
a wooden cell bar, resembling the bottom bar of the frame but is suspended
horizontally from about middle of the frame. This bar should be easily removable
or rotatable to facilitate grafting of the larvae into attached cell cups. The cell
cups can be directly attached to the wooden bar having a thick layer of beeswax. It is, however, more convenient to attach the cell cups to flat pieces of soft
wood and these pieces are then / attached glued to the cell bar ,at a spacing
of 2.5 cm ( i.e.1 inch ) apart each, by dipping them in molten wax and then
more molten wax is reinforced at their basis with the help of a spoon . Small
wax blocks or cork pieces can also be used for affixing queen cell cups for the
easy removal of mature queen cells upon sealing.
iii) Larval grafting : The next step in the process is the transference of frame
grafted with the young larvae to the cell cups which must be done in the room
with controlled temperature (34-35°) and humidity. Younger larvae (less than 24
hours) are more easily accepted by nurse bees for queen rearing. Before larval
grafting, the cell cups may be offered to a colony for an overnight for the bees to
work on the cells and polishing in order to make them more acceptable. The
larval grafting can be dry grafting ( grafting the worker larvae of appropriate
age in the queen cell cup without priming the cell cups with royal jelly) ; wet
grafting (grafting the worker larvae after priming the queen cell cup with royal
jelly) or double grafting (to ensure sufficient amount of royal jelly for nursing
the queen, first grafted larvae are removed after 24 hours and then new young
larvae of 12-24 h age are regrafted into those cell cups). Remove the selected
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larvae of about 24 hours age, one at a time with a grafting needle and float them
off on the royal jelly in the cell cups. Less than one day old larvae are very
delicate, therefore, a great care must be taken so that no physical damage is
done to them during their transfer to the cell cups. While grafting the larvae, its
original position should not be changed. The frame with the grafted larvae is
then given to the queenless cell builder colony.
iv)
Queen cell construction : In each method discussed in the preceeding text
the main objective is to raise a large number of queen cells in the cell builder
colony. The queen cells are sealed in about 10 days. Hence, it becomes
imperative that before the emergence of the queens the sealed cells are transplanted one by one to the queen mating nuclei or to the dequeened colonies
demanding queen replacement.
6. Karl-Jenter and Cup-kit system : These queen rearing systems help the beekeeper
to rear queen bees without grafting. The basic idea behind developing these systems
is to make queen rearing an easy task for beekeepers.
The cell-plug queen rearing method is similar in most ways to other queen rearing
methods, but overcomes difficulties. The method involves confining the breeder queen in
a plastic comb box, where she lays eggs in cell plugs made of PVC. These cell plugs
or cups are removable by opening the basal cover of the comb box. The complete kit
comprises: plastic comb box, brown cell cups, cell bar blocks and cell cup caps. Small
brown cell cups are first loaded into back of the comb box. On front side of comb box are
hexagonal tubes that simulate normal cells. Take a relatively old comb and cut out a
piece, of the size of the Jenter/Cup kit apparatus, in the top center.
A few days later when eggs hatch, move the plugs, now each containing young larva,
into queenless cell-raising colonies by fixing on the queen rearing frame. The cell-raising colonies feed and care for the queen cells. When the queens are ready to hatch,
each cell is moved to a mating nucleus.
TRANSPLANTING SEALED QUEEN CELLS
This is an important operation in queen rearing and the success lies in the accuracy
and precision of this operation. Since a large number of queen cells are raised at a time,
one should prepare in advance an equal number of nucleus colonies or nucs to which
these sealed queen cells are to be transplanted. Nucleus hives/nucs should have sufficient number of worker bees of all ages, mature drones and sufficient quantity of food
reserves so that the emerging young queen is attended well in the colony. Before actual
transplantation of a queen cell, it must be ensured that the workers in the nucleus hives
already have felt the absence of the queen at least 24 hrs. prior to the transplantation
otherwise, the chances of tearing off immature queen cells by the recipient colony workers can not be ruled out. Removing the queen cell from the cell builder colony and
transplantation into the nucleus hive is an operation, which needs a good amount of
experience. Individual queen cells are scrapped off at the base with a sharp edged knife.
The cells removed in this way should be transplanted just near the brood area and it
must be ensured that it is properly fixed on the raised comb in the recipient colony. The
134
transplanted cells should be fixed in such a way and at a location (i.e. just adjacent to
the brood area) on the frame that it is properly covered by the bees and is not injured in
any way when the comb is placed in the colony.
After the successful transplantation the young queen emerges out from the cells
within a couple of days. Alternatively, sealed queen cells are covered with queen emergence cages with the provision of candy. After the queens emerge they are introduced
into queen less mating nuclei. The queen may mate within a week's time. The mating
nuclei should be placed in staggered position/direction in mating yard before the emergence of queens from the cells. The emergence of the young queens should coincide
with the peak period of drone population of required age in the mating yard so that the
successful mating of the virgin queen is ensured. The direction of the mating nuclei
should not be changed/disturbed till the mated queen starts oviposition.
Suggested Readings
Laidlaw, H. H. 1985. Contemporary Queen Rearing . Dadant and Sons, Hamilton, Illinor,
USA.
Ruttner, H. 1983. Maintaining queen during the mating period. In Ruttener, F. (Ed.) Queen
Rearing, Biological basis and Technical Instinction . Apimondia Publishing House.
235-277.
Woyke, J. 1967. Rearing conditions and the number of sperms reaching the queen's
spermatheca. XXI. Int. Apin. Cong. Romania : 232-234.
135
HONEY BEES : MANAGEMENT AS POLLINATORS
Yogesh Kumar
Department of Entomology,
CCS Haryana Agricultural University, Hisar
A number of agents performs the function of transfer of pollen from plant to plant,
because some pollens are dry and light and others are moist and heavy. The common
agents of pollen transfer are gravity, wind and insects.
Role of bees
Bees are the most important insects for pollination of crops. The wild bees including
bumble bees, leaf-cutting bees, alkali bees and carpenter bees are specially adapted for
gathering pollen and nectar from flowers. Many other insects such as beetles, flies,
moths and thrips that visit flowers purposely or accidentally can be agents for carrying
pollen grain from the anther to the stigma. But of all these the most important are the
honey bees (Apis cerana, A. florea, A. dorsata and A. mellifera ) whose existence
depends on flowering plants. Under certain circumstances, even honey bee collected
pollen can also be utilized for pollination of the crops. Because of being active foragers,
the hive bees can also be utilized as pollen dispensers for increased crop pollination.
Two species of honey bees are effectively managed and utilized for pollination purpose.
These are Apis mellifera L. and A. cerana F. Honey bee species can effectively be
utilized for pollination of crops because :
Honey bees are dependent on flowers for pollen and nectar as their food.
The bees possess some morphological adaptations favourable for pollen carry over
and transfer.
The honey bees can be kept in the hives and are very easy to be managed.
Due to their polylectic nature, honey bees visit large number of plants, therefore,
they can pollinate a wide variety of crops.
There abundance on the crop can easily be manipulated.
Honey bees have better communication system for food searching and gathering.
When a honey bee forager begin foraging on a plant species, it continues to do so
until the resource gets exhausted. This behaviour of individual foragers has been
termed as floral fidelity or constancy. This is very important for the plant species
they visit for the effectivity of pollination.
Behaviour of honey bees can be manipulated by modifying the reward system of the
plant/or nectar and pollen storage in the hive or colony's unsealed brood.
Colonies of honey bees can be moved to a place of short pollinators supply.
Management of honey bee colonies for crop pollination
Honey bees can increase the quality and quantity of most crops. Weak colonies are
of little use in pollination, so one must manage the honey bee colonies to produce large
136
populations of foraging bees just as for honey production. For effective pollination of
crops, following points are taken into consideration.
Time of placement of honey bee colonies
When 5-10 per cent of the flowering has initiated, honey bee colonies are placed on
the crop.
Colony strength
Strong colony should be placed after flowering of the crop starts to attract more
foragers. Brood area and number of combs occupied by bees is a good index of the
strength of bee colony.
The colonies should meet the following requirements.
(i) Bee strength
=
8-10 frames
(ii) Unsealed brood
=
3 frames
(iii) Sealed brood
=
2 frame
(iv) Honey
=
2 frames
The colonies should have a new mated queen and these should be free from any
diseases and pests. Other general and specific management practices required for
honey bee colonies are also to be observed.
Concentration of colonies/ha
It depends upon the following factors:
a) No. of honey bees
b) Other pollinators
c) Size of crop
d) Competitive plants of the same and different species.
Site of placement of honey bee colonies
The colonies are placed near the target crops so that they can actively move and
bring about cross pollination and less energy is utilized in traveling.
Honey bees can visit upto 11.3 km but 0.4 km is the excellent distance. Nearer the
source of forage greater the economy. Less time is taken to collect pollen load than
nectar load and thus shift to pollen collection if the crop is near the hive.
Method of placement of honey bee colonies
The colonies are placed either in groups or are scattered, and further, either around
the target crop or scattered in between as per the convenience of the beekeeper.
137
Conditioning colonies to a particular crop
Shift colonies to crop only after flowering. If insect pests appear, crop should be
sprayed before the initiation of flowers. Use only insecticides safe to honey bees and
close the entry of boxes on the proceeding night of spraying. However, the colonies
should not suffer of want of sufficient ventilation.
Feeding the scent of target crop to honey bee colonies :
Immerse flowers of the crop in sugar syrup for some hours. Remove the flower and
feed the syrup to the colonies kept for pollination service.
Feeder containing scented sugar syrup & moving it to the site of crop directs the
bees to the crops.
Number of colonies needed
On an average, five colonies per hectare are needed for fruit orchards, but the need
vary with place-to-place and crop-to-crop. Factors affecting bee visits are :
i)
Use of fertilizers
ii) Number of irrigations
iii) Spacing of plants
iv) Wind breaks
v)
Competitive crops
vi) Variety of the crop
vii) Infestation by insect - pests
Increasing the attractiveness of crops
Breeding of varieties of crops that produce more nectar and pollen of good quality.
Optimum doses of fertilizers should be applied so that physiology of the crop is not
disturbed.
Wide spacing encourages bee visits.
Excessive irrigation dilutes the nectar and make it unattractive to honey bees.
Foraging areas of colonies depends upon quantity of pollen and nectar weather conditions, physical features etc.
Increasing the proportion of pollen gatherers on crops
More brood needs more pollen, which engages more pollen collectors. Colonies which
contain brood should be preferred over new ones.
Use of pollen traps increases, more pollen collections but it can result in loss in
honey collection and loss in brood rearing.
138
Pollination aids :
Pollenizers
A pollenizer is a plant variety that provides a source of compatible pollen for use in
cross-pollination. If the main variety selected by the grower is self-sterile, the interplanting of pollenizers with compatible pollen is essential for fruit production. Apples provide
a good example of pollenizer plantings.
Pollen dispensers or inserts
Pollen dispensers are devices which are fitted at the entrance of bee hives and hold
pollen of desirable pollenizer varieties in such a way that the bees dust themselves with
the pollen as they leave the hive. Inserts may be an attractive option with orchards with
no pollenizers planted nearby (Mayer and Johansen, 1988).
Pollen traps
Pollen traps are used at the hive entrances to harvest pollen loads of foraging bees.
Use of pollen traps increases the proportion of bees foraging for pollen because these
induce a pollen deficit in the colony.
Honey bee attractants
Honey bee attractants are products designed to increase bee visitation to treated
crops with the aim of increasing pollination. These products are mixed with water and
applied to crops with conventional spray equipment. The research support for these
products is generally not strong but more work is certainly warranted (Winston and
Slesser, 1993).
Disposable pollination units
Disposable pollination units are small colonies housed in inexpensive containers
and whose sole purpose is pollination. They are destroyed or left to die after flowering is
over. Disposable pollination units may be attractive for growers in remote areas or for
bee keepers with surplus bees. However, these units have not been widely adopted.
Suggested Readings
Ahmad, R. 1987. Honey bee pollination of important entomophilous crops. Honey Bee
Research Programme. Pakistan Agricultural Research Council, Islamabad. pp.103.
139
A SIMPLE TECHNIQUE TO HIVE LITTLE BEE COLONIES
M. Muthuraman, S. Kaliamoorthy, N. Ganapathy, G. K. Thangavel,
P. Priyadharshini and K.Bharathidasan
Department of Agricultural Entomology,
Tamil Nadu Agricultural University, Coimbatore 641 003
Dwarf honey bees are the most common honey bees found in India. There are two
species of dwarf honey bees viz. , Red dwarf honey bee, Apis florea and Black dwarf
honey bees, Apis andreniformis. The workers of A. florea are generally reddish brown
and are widely distributed in India. A. andreniformis is generally black and its distribution in India is restricted to Assam.
Unique characters
A. florea thrives very well in hot, dry climate. It builds single comb in open air.A.
florea builds single comb and it is not very defensive. A band of sticky resin is deposited
around the branch that supports their nests to ward off ants. The bees cannot tolerate
even minor interference. They adopt a defense strategy of flight instead of fight and
desert their nest when the colony is disturbed. This absconding habit mainly deters the
attempts to domesticate these bees. Little bee colonies never stay in the same place
for a long time Most of the colonies undergo at least one migration per year in search of
flora. When it migrates, the flight range of the swarm is restricted. The swarming process always leads to the dissolution of colony.
Habitat
Densities of A. florea can be very high in places where floral resources are rich.
Recent bee faunal and floral survey conducted in Tamil Nadu has clearly revealed the
scope for keeping florea colonies in places where banana is cultivated extensively and
also in tank beds where Acacia nilotica and A. planifrons trees are grown. The nest
densities of A. florea are also found to be high in energy plantations established with
Prosopis juliflora . This tree is usually well preferred by the bees for their nesting. In
addition, it is also a major source of nectar and pollen for the bees.
Importance
The annual honey yield from a colony varies from one to three kilograms. It is
believed that little bee honey has more therapeutic properties. This honey has higher
dextrin content and has less tendency to granulate than the honey of other Apis
species. A. florea colonies are abundant in the forest and as well as agricultural belts of
Kutch region in Gujarat during March-April and in October-November. From this region
alone Gujarat State Forest Department gets 100 tonnes of florea honey annually. There
is an urgent need to upgrade the skill of honey collectors about hygienic method of
honey collection without hunting the bees and their brood nest and proper utilization of
bees wax, a precious nest product A. florea is an excellent pollinator of field and
orchard crops. A simple technique of shifting little bee colonies to chosen shady places
140
would facilitate planned pollination in orchards and other agroecosystems for pollination
and honey production. The hive design and the technique of capturing feral colonies of
little bees recently developed are described below.
Card board box hive
The hive is simple in design and made of card board (Fig. 1). The hive is very well
suited for the purpose of transportation and maintenance of feral colonies. The
dimensions of the card board box hive are fixed according to the size of the feral colony.
Two 'U' shaped cuts are made on each side along the side walls of the card board box
that serve as rabbets. The width of the cuts depends on the thickness of the twig to
which the comb is attached. Similarly, the depth of the cuts is also varies with the
height of the honey crest so as to accommodate the honey crest conveniently within the
hive even after closing the card board box using the top lid. Small holes of 2 mm diameter are made on the sides and the front wall of card board box for ventilation. The
perforations permit only air movement and not the bees. A rectangular opening is cut on
the front wall of the hive along the perforations to facilitate the landing and take off by
foraging bees from their nest after shifting the colonies to the chosen location.
Hiving of feral colonies
Arboreal nesting colonies are mainly hived. The twig with comb is gently cut using
either a secateur or a small hack-saw blade with least disturbance to the comb and
bees. Most of the bees that fly out while cutting the twig hover in air or settle near their
nesting sites. The twig with the comb thus removed is kept inside the card board box
hive in the 'U'shaped rabbets. Later the card board box hive with the comb is kept closer
to the original nesting site with top lid open. All the bees settle on the comb within 15-30
minutes. Then top lid of the hive is closed. All the edges of the hive are sealed by using
gum tape prior to transport and the hive is made bee proof.
The card board hive serves the twin purposes of colony transport and providing comfortable lodging for the bees. The large opening provided in the front wall of the hive
almost creates an open nest situation. In addition, the hive also provides additional
protection to the colony against heat and rain. The new hive makes colony inspection
easy and possible at all times. Dead bees, discarded eggs and hive debris found at the
bottom floor of the hive will be helpful to monitor the changes in bee behaviour inside the
hive.
Transport of hived colonies
The feral colonies of A. florea thus hived in card board box hives are transported to
selected location using either a two wheeler or a four wheeler after dusk. Colony
removal, hiving and shifting are mainly done during the evening time to avoid the loss of
field bees. Care should be taken to minimize jerks during transport to avoid breakage
of combs. The front lid on the front wall of the hive is removed after reaching the
destination.
141
The following are the precautions to be followed during hiving process and subsequent transport of hived colonies :
Do’s
Hive the colonies that build nests on tree branches encircling twigs.
Hive the colonies especially during nectar flow season.
Hive the nest either during early morning or late evening.
Choose the appropriate cutting tool according to the size of the twig. A thin twig is
easily cut with secateur while a hack- saw blade is suited for cutting a thick twig.
Cut the twig with extreme care so as to avoid detachment of comb from twig.
Use minimum quantity of smoke with a small bunch of coconut husk and calm the
bees before cutting the twig.
Delay the shifting of nest until all the bees settled back on the comb.
Transport the hived colonies with minimum jerk.
Don'ts
Do not hive the colonies with either white or yellow coloured comb
Do not hive the colonies that are queenless.
Do not hive the colonies that are ready to swarm.
Do not hive the colonies that are about to abscond.
Do not hive the colonies that where the combs are not totally covered by bees.
Do not hive the colonies with patchy brood.
Avoid using excess smoke while removing the nest along with the twig.
Do not catch the queen with fingers as handling queen may inflict injury to her.
Do not expose the naked comb to direct sunlight to avoid melting of combs and
comb detachment from the twig after settling of bees.
Never alter the angle of the twig with respect to ground while replacing the nest
inside the hive (Fig. 1 and 2).
Conclusion
The new method to hive the little bee colonies with card board boxes will be helpful
to partially domesticate these wild bees. The hived colonies can remain inside the hives
at least for a few months. During the period of confinement the colonies can be used for
sustainable honey harvest and planned pollination of crops in the farm. In addition, it will
be a boon for the researchers to make in-situ observations about the bees.
142
Fig. 1. Colony kept inside the hive
Fig. 2. Hive with colony
REQUIREMENT OF FLORA IN RELATION TO
BEE POLLINATOR SPECIES
SunitaYadav and H. D. Kaushik
Project Coordinator Cell, AICRP on Honey Bees and Pollinators,
CCS Haryana Agricultural University, Hisar 125 004, Haryana
There are thousands of insect species which contribute to pollination, such as, bees,
wasps, occasionally ants (Hymenoptera), beetles (Coleoptera), moths and butterflies
(Lepidoptera), and flies (Diptera). India is endowed with the greatest biodiversity as far
as honey bee species are concerned. All the four Apis species i.e. Apis mellifera, A.
cerana, A. dorsataand, A. florea are present in India. In addition to these several other
bee species including Stingless bees ( Teregene ), Bumble bees ( Bombus spp.), Orchard
bees ( Osmia spp.), Leafcutting bees ( Megachile spp.), Alkali bees ( Nomia spp.),
Carpenter bees (Xylocopa spp.), Digger bees ( Andrena spp.) etc. are also known to
occur in the country. A. mellifera and A. cerana are the only members of the pollinating
insects that offer opportunities for management and manipulation by man and thus dominate Indian beekeeping and commercial pollination. But in addition to these wild and
domesticated non-Apis bees also effectively complement pollination in many crops e.g.
bumble bees used primarily for the pollination of greenhouse tomatoes, the solitary bees
Nomia and Osmia for the pollination of orchard crops, Megachile for alfalfa pollination,
and social stingless bees to pollinate coffee and other crops.
For insect pollinators, their forage or food supply consists of nectar and pollen from
blooming plants within their flight range. Nectar is the chief source of carbohydrates and
pollen is source of all other dietary requirements. Insect pollinators need nectar to meet
their day-to-day energy requirements whereas social honey bee salso use it for maintaining brood temperature. In order to preserve nectar for future needs, social bees store
it as honey in comb by partially digesting the complex sugar molecules and removing
about 3/4th of the water from it. Nectar is produced by floral and extra floral nectaries of
the plant. Both quality and quantity of nectar influence the floral preference of the insect
pollinators.
Pollen contains 16-30% protein, 1-7% starch 0-15% sugars, 3-10% fats, and 1-9%
ashes (Stanley and Linskens, 1974). Most insects eat the pollen while they are visiting
the flower, but honeybees ( Apis mellifera ) and bumblebees ( Bombus spp.) take it back
to the hive for rearing brood. The collection of large pollen loads is one of the reasons
that bees and bumblebees are such effective pollinators.
Bee flora
Not all plant species are good source of nectar and pollen. Plants producing nectar
but little or no pollen are considered as honey plants. Other plants, yielding pollen but
little or no nectar are called as pollen plants and are important at the time of colony
build-up, when the bees need large amounts of the protein contained in pollen for their
brood-rearing. The plants that providenectar or pollenor both are collectively called as
143
bee forage plants or bee pasturage or bee flora. The period during which plenty of flowering plants, providing nectar or pollen or both are availablein succession is called a honey
flow period. There can be major or minor honey flow period. If the flowering plants are
available in abundance to be foraged by honey bees and bees attain good colony strength
and collect surplus honey in combs, it is called a major honey flow period. When the
amount of nectar collected is small, it is called a minor flow period and the days when
there is no honey flow is called a dearth period.
Floral Calendar
A floral calendar for beekeeping is a time table that indicates the approximate date
and duration of the blossoming period of the important honey and pollen plants in the
area. Preparation of a floral calendar for any specific area requires the complete observations of the seasonal changes in the vegetation patters and /or agro ecosystems of
the area. The preparation of an accurate detailed calendar will therefore often require
several years of the repeated recording and refinement of information obtained. The steps
normally taken in building up a floral calendar are as follows :
1. Make a general survey of the area; draw up a list of flowering plants found specialy
plants with a high floral population density per unit area or per tree.
2. Place several strong honeybee colonies in the area and inspect the hives regularly
for any change in the amount of food stored within the hive to determine whether it is
depleted, stable or increasing. Any food gains or losses can be monitored accurately by weighing the hives.
3. Survey the areas in the vicinity of the apiary and within the flight range of the bees,
to record the species of plants that the bees visit.
4. Determines whether the plants are visited for nectar or pollen or both.
5. Study the frequency with which the bees visit each flower species, in relation to
changes in the level of the colonies' food stores. If there is a continuous increase in
food stores, in direct response to the availability of the plants visited, the plants are
good forage sources. When the food stores remain stable, the plants can be depended upon to meet the colonies' daily food requirements, but they cannot be classified as major honey sources.
6. Carefully records all the changes in the blossoming of the plants visited. When the
colonies begin to lose weight, the flowering season is finished for all practical purposes.
Once all the data on forage species have been assembled and repeatedly verified,
they should be judged as they relate to the actual performance of the honeybee colonies. The calendar can then be drawn up in the form of circular or linear charts, showing
the weekly or monthly availability of each plant and their flowering sequence. Floral
Calendar of respective areas of the state/ district/localities has been prepared by the
concerned institution or agencies.
144
How to ascertain nectar or pollen source for the pollinators
Sources of nectar : The floral nectaries are deep seated and cannot be seen with
nacked eyes. The pollinators visiting the flowers are held from sideways by the anterior
region of abdomen between the thumb and fore finger and the anterior abdominal part is
slightly pressed. A drop of glistening liquid material is observed at the tip of its tongue
(proboscis). This liquid drop is transferred on the prismatic surface of a hand held refractometer (0-32). If it shows some reading above zero, the pollinator is collecting nectar.
But if it showed zero reading, it is not a nectar collector. Alternatively, we can taste the
liquid drop. If it is sweet the pollinator is collecting nectar otherwise not. A pollinator
inserting its proboscis in to the floral nectaries during foraging can also be taken as a
nectar forager.
Pollen source : Pollens also essential part of bee food for stimulating brood rearing
and colony growth. All plant species yield pollen in varying amounts. Various species of
bees have specialized pollen-carrying structures; known as the scopa, which is on the
hind legs of most bees, and/or the lower abdomen (megachilid bees), made up of thick,
plumose setae. Honey bees, bumblebees, and their relatives do not have a scopa, but
the hind leg is modified into a structure called the corbicula (pollen basket). Most bees
gather pollen to nurture their young, and inadvertently transfer some among the flowers
as they are working.
Assessment of potential bee floral areas
For the selection of the potential bee floral area, it is essential to know the plants,
which provide nectar or pollen to bees. This requires collection of data on different aspects for couple of years to establish the potentials of an area for beekeeping. Scale
colony can provide useful information. Weight of the scale colony can be regularly recorded and the changes in weight can be correlated with the flowering plants, which are
being visited, by bees and also the weather conditions. Flowers present nectar and
pollen during specific time of the day, therefore, bee activity on the flora should be
carefully recorded. Recording the bee activity at different day hours should give useful
information. Melissopalynological studies can also help to ensure which plants are availed
by bees. Pollen analysis of honey samples taken at different time of the year and comparing with reference slides give the exact information about the floral sources for bees
in vicinity. Bee flora should be studied from different angles to find out the value of bee
forage. Some flowers secrete nectar only for one day and few others for short time and
still there are flowers like Scheffiera wallichiana , which continue nectar secretion for
about a fortnight. The blooming period is another important point to determe the value of
flora. In some forages the duration between the start and end of flowering is very short,
whereas in others like Brassica spp. there is a succession of flowering and it lasts for
about a month. Trees present larger number of flowers as compared to bushes, shrubs
and crop plants unless the latter are growing in large continuous areas. Concentration of
nectar sugar gives an objective measure. Total sugars per flower per day are the sugar
value which is normally estimated for such studies. Sugar value is the number of mg of
sugar secreted by one flower over a period of 24 hr. However, total quantity of nectar
145
produced and the amount available to or harvested by bees give valuable information
(Abrol, 2010).
The following guidelines for the exploration and evaluation of potential beekeeping
areas may be found useful :
1. Refer to lists of known major bee floral plants in other countries or regions with
similar vegetation patterns, agro-ecosystems, climate and edaphic conditions;
determine whether similar plants are to be found in the area under study.
2. The seasonal occurrence, in unusually high numbers, of wild (feral nests) of
nativehoneybees can often indicate that there is ample forage in the area, at least
during the period in question.
3. The mere presence of flowering trees and shrubs in limited numbers, or of a few
hectares of land covered with good honey plants preferred by insect pollinators,
does not necessarily indicate that the area has potential for commercial beekeeping.
4. Good honey plants are characterized by relatively long blossoming periods, high
density of nectar-secreting flowers per plant or unit area, good nectar quality with
high sugar concentrations; and good accessibility of the nectaries to the bees.
5. The supporting capacity of an area for honey production is best determined by
monitoring weight changes in the bee colonies.
6. The large scale planting of honeybee forages has never been proved to be a
profitable approach in terms of net economic return, except in integration with other
agricultural activities, such as reafforestation, roadside plantings, animal pasture,
etc.
Beeflora of India
Large number of plants such as coconut, areca nut, red oil palm, date palm, cacao,
mango, custard apple, jujube, cinnamon, clove, cashew, fodder legumes, coriander, cumin,
dill seed, fennel, fenugreek, garlic, turmeric, ginger and other spice and condiment crops,
road side plantations that contribute to honey production like eucalyptus, karanj, tamarind, gulmohr, peltaphorum and soap nut. Hedges and fence plants like mehndi, duranta,
mulberry, justicia and jatropha, do also add to the bee forage value of farms and orchards.
Cereals in general are not very useful as sources of bee forage. However, jowar, bajra
and maize are valued for their pollen, particularly during the Kharif and Rabi crop seasons, when natural sources are scarce. In the case of jowar, some varieties produce
sugary exudation on the nodes. Leaves also secrete a thick sweet liquid when infected
by rust fungi. In both cases bees collect the sweet substances.
Many pulse and oilseed crops are good sources of bee forage. Among the plantation
commercial crops, coffee, orange and other citrus fruit, apple and other pomaceous fruit
species, cardamom and rubber tree are important from the beekeeping point of view.
146
Rubber plantations are found in southwestern and northeastern parts of India, where
tropical humid climate prevails. Next importance plant is litchi tree. The entire.North
India from West Bengal to Jammu has large areas under litchi orchards that constitute
an excellent source of nectar during March to May. Some garden species like railway
creeper, ocimums, salvias, coleus, poinsettia, petunia, zinnia, phlox, and daisy contribute to the bee forage in the otherwise useless areas under gardens and parks. Many
workers have evaluated the bee floral plants of different locations useful for bees (Atwal
et al ., 1974; Deodikar and Suryanarayana, 1977; Pratap, 1997). The detailed list of bee
flora with scientific name, common name, period of flowering and availability of nectar
and pollen are given in Table 1.
Table 1.
S.
No.
Bee flora of India
Scientific Name
20.
Field crops
Eleusine coracana
Oryza sativa
Pennisetum tyhhoides
Sorghum bicolor
Zea mays
Fagopyrum esculentum
Legume Crops
Cajanus cajan
Cicer arietinum
Dolichos biflorus
Medicago sativa
Phaseolus mungo
Phaseolus radiatus
Pisum sativum
Sesbania aegyptica
Sesbania graniflora
Trifolium alexandrium
Vigna unguiculata
Oilseed Crops
Arachis hypogea
Brassica campestris var.
sarson
Brassica campestris var. toria
21.
Brassica juncea
22.
23.
Brassica napus
Brassica nigra
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
Common
name
Family
Flowering
period
Source
type
Ragi
Rice
Bajra
Jowar
Maize
Buckwheat
Poaceae
Poaceae
Poaceae
Poaceae
Poaceae
Polygonaceae
3-4
9-10
11-10
9-10
1-12
7-9
P2
P1
P2
P2
P3
N1
Red gram
Bengal gram
Horse gram
Lucerne
Black gram
Green gram
Peas
Sesbania
Dhiancha
Berseme
Cowpea
Fabaceae
Fabaceae
Fabaceae
Fabaceae
Fabaceae
Fabaceae
Fabaceae
Fabaceae
Fabaceae
Fabaceae
Fabaceae
8-11
12
10
3-4
8 - 10
8
8-9
10-11
6- 7
3-4
8
N3P2
N2P2
N1P1
N2P2
N1
N1P1
N1
P1
P1
N3P2
N1P1
Groundnut
Sarson
Fabaceae
Brassicaceae
8-9
10-11/10-1
N2P2
N1P1
Toria, Indian
rapeseed
Raya, Indian
mustard
Rapeseed
Black mustard
Brassicaceae
10-11
N1P1
Brassicaceae
12-2
NP
Brassicaceae
Brassicaceae
12-3
8-9
N1P1
N3P3
147
24.
25.
26.
Brassica rapa
Carthamus tinctorius
Eruca sativa
27.
28.
Guizotia abyssinica
Helianthus annuus
29.
30.
Linum ustitassium
Ricinus communis
Fiber Crops
Corchrus olitorius
Gossypium arborium
Hibiscus cannabinus
Crotolaria juncea
Vegetable crops
Abelmoschus esculentus
Allium cepa
Amaranthus viridis
Brassica oleracea capitata
Brassica oleracea botrytis
Capsicum annum
Capsicum chinense
Coccinia indica
Coriandrum sativum
Cucumis melo
Cucumis sativus
Cucurbita maxima
Daucus carota
Dolichos lablab
Glycine max
Ipomea batatus
Lagenaria vulgaris
Laginaria siceraria
Luffa acutangula
Lycopersicon esculentum
Momordica charantia
Moringa oleifera
Phaseolus vulgaris
Raphanus sativus
Solanum melongena
Solanum tuberosum
Trigonella foenumgracum
Plantation Crops
Cocos nucifera
Coffea arabica
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
43.
44.
45.
46.
47.
48.
49.
50.
51.
52.
53.
54.
55.
56.
57.
58.
59.
60.
61.
62.
63.
Turnip, Canola
Safflower
Taramira,
Rocket
Niger
Sunflower,
Surajmukhi
Linseed, Flax
Castor
Brassicaceae
Asteraceae
Brassicaceae
2-4
12-1
12-8
N2P2
N3P2
N2P2
Asteraceae
Asteraceae
4-5
1-12
N1 P3
N1P3
Linaceae
2-3
Euphorbiaceae 8-9
N2P2
N1P1
Jute
Cotton
Kenaf
Sun hemp
Malvaceae
Malvaceae
Malvaceae
Malvaceae
3-4
4-1
4- 6
8-11
N2P2
N1P1
N1P1
N3
Lady's finger
Onion
Amaranthus
Cabbage
Cauliflower
Chilli
Capsicum
Little gourd
Coriander
Muskmelon
Cucumber
Squash gourd
Carrot
Field bean
Soybean
Sweet potato
Pumpkin
Bottle gourd
Ridge gourd
Tomato
Bitter gourd
Drumstick
French bean
Radish
Brinjal
Potato
Methi
Malvaceae
Liliaceae
Amaranthaceae
Brassicaceae
Brassicaceae
Solanaceae
Solanaceae
Cucurbitaceae
Apiaceae
Cucurbitaceae
Cucurbitaceae
Cucurbitaceae
Apiaceae
Fabaceae
Fabaceae
Convolvulaceae
Cucurbitaceae
Cucurbitaceae
Cucurbitaceae
Solanaceae
Cucurbitaceae
Moringaceae
Fabaceae
Brassicaceae
Solanaceae
Solanaceae
Fabaceae
1-12
5-7
1-12
2-4
2-4
1-12
11-2
1-8
2-3
3-4
10-11
2-3
3-4
9
8-9
10-12
3-9
1-12
11-2
1-12
4-7
12-4
1-12
2-4
1-12
12-2
1 -12
N3P2
N3P3
N1
N3P2
N3P2
N3P1
N3P1
N3P2
N1P1
N3P2
N3P2
N3P1
N2P2
N2P1
N1P2
N1P1
P1
N3P2
N3P1
P1
N2P2
N1P1
N1P1
N3P1
P1
P1
N1
Coconut
Coffee
Arecaceae
Rubiaceae
1 -12
4-5
P3
N3P1
148
64.
65.
66.
67.
68.
69.
70.
71.
72.
73.
74.
75.
76.
77.
78.
79.
80.
81.
82.
83.
84.
85.
86.
87.
88.
89.
90.
91.
92.
93.
94.
95.
96.
97.
98.
99.
100.
101.
102.
103.
104.
105.
Hevea brasiliensis
Nicotiana tabaccum
Fruit Crops
Anacardium occidentale
Annona squamosa
Areca catechu
Artocarpus integrifolia
Averrhoea carambola
Carica papaya
Cinnamomum verum
Citrus spp.
Citrus medica var acida
Fragaria spp.
Litchi chinensis
Malus domestica
Mangifera indica
Manilkera achras
Muntingia calabura
Musa paradisiaca
Phoenix dactylifera
Prunus armeniaca
Prunus domestica
Prunus dulcis
Prunu spersica
Psidium guajava
Punica granatum
Pyrus communis
Rubus spp.
Sechium edule
Sesamum indicum
Syzigium cumini
Syzigium jambos
Vitis vinifera
Ornamental Plants
Ageratum conyzoides
Antigonon leptopus
Aster thomsoni
Barleria cristata
Calendula officinalis
Callistemon lanceolus
Cassia spp.
Celosia argentea L. var cristata
Celosia argentea L. var
plumosa
Chrysanthemum coronarium
Rubber
Tobacco
Euphorbiaceae 3
Solanaceae
12-1
N1
P1
Cashewnut
Custard apple
Arecanut
Jack fruit
Carambola
Papaya
Cinnamon
Citrus
Acid lime
Strawberry
Lychee
Apple
Mango
Sapota
Singapore cherry
Banana
Date palm
Apricot
Plum
Almond
Peach
Guava
Pomegranate
Pear
Rasberry
Chow chow
Sesamum
Nerala
Rose apple
Grape
Anacardiaceae
Annonoceae
Arecaceae
Moraceae
Averrhoaceae
Caricaceae
Lauraceae
Rutaceae
Rutaceae
Rosaceae
Sapindaceae
Rosaceae
Anacardiaceae
Sapotaceae
Eleocarpaceae
Musaceae
Palmae
Rosaceae
Rosaceae
Rosaceae
Rosaceae
Myrtaceae
Punicaceae
Rosaceae
Rosaceae
Cucurbitaceae
Pedaliaceae
Myrtaceae
Myrtaceae
Vitaceae
12-2 9-10
4- 6
1 -12
12-3
5-7
7-9
12-2
2-3
1 -12
5-9
3-4
3-4
12-3
10-3
1-12
1 -12
6-7
3-4
2-3
5-8
2-3
2-4
4-7
2-8
2-6
8
4-9
2-5
12- 4
9-12
N2P1
N1P2
P3
P1
N3P1
N3P2
N2
N1P1
N1P1
N2 P2
N1
NP
N1P1
N1
N2P1
N1P1
N2P3
N1P1
N1P1
N1P1
N2P2
N3P3
N1P2
N2P2
N3P2
N1P1
N3P3
N2P
N3P2
N2P1
Ageratum
Mexican creeper
Aster
Barleria
Calendula
Bottle brush
Cassia
Cockscomb
Celosia
Fabaceae
Polygonaceae
Asteraceae
Acnthaceae
Asteraceae
Myrtaceae
Caesalpinaceae
Amaranthaceae
Amaranthaceae
12-3
4-5
8 - 10
1-12
6-10
5-7
4-7
1-8
1-8
N1P1
N3P3
N1P1
N1P2
N3P1
N3
N2P2
N1
N1
7-10
N1P1
Chrysanthemum Asteraceae
149
106.
107.
108.
109.
110.
111.
112.
113.
114.
115.
116.
117.
118.
119.
120.
121.
122.
123.
124.
125.
126.
127.
128.
129.
130.
131.
132.
133.
134.
135.
136.
137.
138.
139.
140.
141.
142.
143.
144.
145.
146.
147.
148.
149.
150.
Cosmos bipinnatus
Cosmos sulphureas
Delonix regia
Euphorbia mili
Euphorbia pulcherrima
Evolvulus glomeratus
Gerbera launiosa
Hamelia patents
Helichrysum arenarium
Hibiscus rosasinensis
Impatiens balsamina
Ipomea carica
Jacquemontia violacea
Jasminium angustifolium
Lagerstromia indica
Melampodium paludosum
Petrea volubilis
Poinsettia pulcherrima
Polyanthus tuberose
Rosa indica
Tagetes minuta
Thevetia peruviana
Zinnia elegans
Zoysia sp.
Medicinal & Aromatic plants
Ammi mages
Anethum graveolens
Apium graveolens
Bacopa monnieri
Bidens pilosa
Carvia callosa
Centratherum sp.
Foeniculum vulgare
Lavandula stoechas
Lathyrus sativus
Lawsonia inermis
Matricaria chamomilla
Mentha spicata
Nepeta cataria
Ocimum basilicum
Ocimum canum
Ocimum gratissimum
Ocimum kilimandscharium
Ocimum sanctum
Porana volubilis
Ruta graveolens
Cosmos
Asteraceae
Cosmos
Asteraceae
Gulmohar
Fabaceae
Euphorbia
Euphorbiaceae
Poinsettia
Euphorbiaceae
Blue daze
Convoulaceae
Gerbera
Agavaceae
Hamelia
Asteraceae
Everlasting flower Asteraceae
Shoeflower
Malvaceae
Garden Balsam Balsaminaceae
Railway creeper Convolvulaceae
Jacquemontia
Convolvulaceae
Wild jasmine
Oleaceae
Pride of India
Lythraceae
Melampodium
Asteraceae
Purple wrath
Verbenaceae
Poinsettia
Euphorbiaceae
Polyanths
Agavaceae
Rose
Rosaceae
marigold
Asteraceae
Kanagila
Apocynaceae
Zinnia
Asteraceae
Mexican grass
Poaceae
3-5
6-11
3-5
11-2
11-2
1-12
1-12
5
1-3
1-12
6-10
1-12
1-12
12-6
2-4
6-10
2-4
11-2
1-12
6-7
1-12
1-12
6-10
4-7
Honey plant
Apiaceae
3-4
Dill
Apiaceae
12-3
Celery
Apiaceae
6-8
Brahmi
Scrophulariaceae 5-7
Bidens
Asteraceae
6-2
Karvi
Acanthaceae
8-10/7-9
Wild cumin
Asteraceae
5-9
Fennel
Apiaceae
4-5
Lavender
Lamiaceae
6-11
Khesari
Euphorbiaceae 3-4
Mehandi
Lythraceae
2-5
Chamomile
Asteraceae
5-9
Spear mint
Lamiaceae
1-12
Cat mint
Lamiaceae
1-12
Sweet basil
Lamiaceae
2-8
Hairy basil
Lamiaceae
1-12
Clocimum
Lamiaceae
1-12
Camphor Basil
Lamiaceae
1-12
Sacred basil
Lamiaceae
1-12
Snow creeper
Convolvulaceae 3-5
Garden rue
Rutaceae
1-12
150
N3P2
N1P1
N1P1
N1P1
N1P1
N1P1
N1P2
N2P1
N3P3
N2P2
N1P1
N2P2
N2
N3P2
P1
N2P2
N2P2
N1P1
N2
N3P3
N2P2
NP
P2
N1P1
N3P3
N3P3
N2P2
N1P1
N2P2
N1P1
N2P1
N3P3
P2
N1P2
N1P1
N3P3
N3
N3P3
N2P3
N1P1
N2P1
N2P3
N2P2
N2P2
N1P1
151.
152.
153.
154.
155.
156.
157.
158.
159.
160.
161.
162.
163.
164.
165.
166.
167.
168.
169.
170.
171.
172.
173.
174.
175.
176.
177.
178.
179.
180.
181.
182.
183.
184.
185.
186.
187.
188.
189.
190.
Salvia spp.
Trachyspermum ammi
Weeds
Abelmoschus ficulneus
Argemone mexicana
Artimesia vulgaris
Crotan sparciflora
Dhatura fistula
Jatropha curcus
Lantana camera
Leucas aspera
Mimosa pudica
Nerium indicum
Plectranthus rugosus
Prosopis juliflora
Stachytarpheta indica
Tridax procumbens
Trees
Acacia arabica
Acacia catechu
Acacia modesta
Actinodaphn ancustifolia
Actinodaphn hookeril
Adhatoda vasica
Aegel marmelos
Aeqiceras corniculatum
Albizia lebbeck
Albizia amara
Azadirachta indica
Bauhinia purpurea
Bombax ceiba
Boreria stricta
Butea monosperma
Callistemon lanceolatus
Canthium parviflorum
Cassia javanica
Ceiba pentandra
Chenopodium album
Crotolaria striata
Dalbergia sissoo
Datura stramonium
Ehretia acuminate
Sage
Ajwain
Lamiaceae
Apiaceae
7-10
3-7
N2P2
N2P2
Van Bhindi
Yellow mexican
poppy
Mugwort
Mirchaiya
Dhatura
Boghandi
Lantana
Leucas
Touch me not
Sormari
Shain/ chhihhri
Mesquite
Stachytarpheta
Tridax
Malvaceae
Papavaraceae
8-9
11-3
N3 P2
N1P1
Asteraceae
Euphorbiaceae
Salanaceae
Euphorbiaceae
Verbenaceae
Lamiaceae
Mimosaceae
Apocynaceae
Lamiaceae
Mimosaceae
Verbenaceae
Asteraceae
2-7
7-8
1-12
9-10
1-12
11-6
1-12
9-10
8-10
7-11
1-12
1-12
N1P2
N3 P2
N3 P2
N2 P2
N1
N2P1
N2P2
N2 P2
N1P3
N3P1
N1
N1P2
Mimosaceae
Mimosaceae
Mimosaceae
Lauraceae
Lauraceae
Acanthaceae
Rutaceae
Myrsinaceae
Mimosaceae
Mimosaceae
Meliaceae
Fabaceae
Malvaceae
Rubiaceae
Fabaceae
Myrtaceae
Rubiaceae
Caesalpinaceae
Bombaceae
7-11
7-9
5-7
10-3
10-1
8-10
5-6
1-2, 7
2-4
1-3
3-4
2-8
1-3
1-12
2-3
1-12
3- 6
3-5
2-4
N1P1
P1
N
N1
N3P1
N3P4
N2P2
N3P2
N1P1
P1
N2
N1P1
N1P2
P1
N1P1
N3P1
N2P2
N1P1
N1
6- 9
1-5
3-4
11-6
4
N1P1
P1
N1
P1
N1
Babul
Khair
Acacia
Pisa
Pida
Maker
Bad
Mangrove
Siris tree
Chigere
Neem
Khairwal
Simal
Boreria
Dhak
Bottle brush
Canthium
Cassia
White silk
cotton tree
White goose foot
Crotolaria
Sissoo
Thorn apple
Puna
151
Chenopodiaceae
Fabaceae
Fabaceae
Solanaceae
Boraginaceae
191.
192.
193.
194.
195.
196.
197.
198.
199.
200.
201.
202.
203.
204.
205.
206.
207.
208.
209.
210.
211.
212.
213.
214.
215.
216.
217.
218.
219.
220.
221.
222.
223.
224.
225.
226.
227.
228.
Elaeagnus umbelata
Wild olive
Eucalyptus spp.
Safeda
Eugenia spp.
Bhedas, Gudda
Gliricidia septium
Gliricidia
Grewia spp.
Phalsa
Jacaranda acutifolia
Jacaranda
Kaya sinegensis
Kaya
Lagascea mollis
Lagascea
Leucaena leucocephala
Subabul
Madhuca longifolia
Madhua
Mallotus philippensis
Kumkum
Manihot glagiovii
Rubber Tree
Michalia champaka
Michalia
Morus alba
Mulberry
Parthenium hysterophorus
Congress weed
Peltophorum ferrugineum
Copper pod
Phyllanthus emblica
Amla
Pithecollovium dulce
Manila
Polygonum glabrum
Polygonum
Pongamia pinnata
Karanj, Sukhchain
Pterospermum personatum
Pterospermum
Rubinia pseudoacacia
Rubinia
Samanea saman
Rain tree
Santalum album
Sandal wood
Sapindus laurifolius
Soap nut
Saraca indica
Saraca
Simaruba glauca
Simaruba
Spathodea campanulata
Scarlet bell
Sterculia foetida
Foetid tree
Tabubia argentia
Tabubia
Tamarindus indica
Tamarind
Tecoma stans
Tecoma
Terminalia arjuna
Arjune
Thelepaepale spp.
Whayati
Toona ciliata
Tun
Wendlandia spp..
Tiliya
Zizyphus jujuba
Wild Ber
Ziziphus mauritiana
Ber
N = Source of nectar; P = Source of pollen
Flowering Period (Month) = January to December (1-12)
Source : 1- Major , 2- Medium, 3- Minor
152
Elaeagnaceae 4-5
Myrtaceae
11-4
Myrtaceae
2-4
Caesalpinaceae 2-4
Teliaceae
7-11
Bignoniaceae
2- 4
Meliaceae
1-3
Asteraceae
7-12
Mimosaceae
1-12
Sapotaceae
2-3
Euphorbiaceae 11-2
Euphorbiaceae 7-8
Magnoliaceae 4- 6
Moraceae
2-6
Asteraceae
1-12
Caesalpinaceae 5-7
Euphorbiaceae 2-4
Caesalpinaceae 2-4
Polygonaceae 12-3
Caesalpinaceae 3-4
Bignoniaceae
4i-5
Fabaceae
9-4
Mimosaceae
3-6
Santalaceae
12-7
Sapindaceae
3-5, 10-12
Caesalpiniaceae2- 4
Simaroubaceae 2-3
Bignoniaceae
1-12
Sterculiaceae
11-2
Bignoniaceae
2-3
Caesalpinaceae 5-6
Bignoniaceae
1-12
Combretaceae 3-5
Acanthaceae
4-1
Meliaceae
3-4
Rubiaceae
2
Rhamnaceae
5-6
Rhamnaceae
3-5
N2P3
N1P1
N1
N1P1
N2P1
N1P1
N2
N3P1
P1
N1
P1
N3
N1
P1
P1
N2P3
N1P1
N1
N1P1
N1P2
N1P1
N1P
N1P1
N1
N1P1
N1
N3P3
N3
P3
N1P1
N1P1
N1P1
N1
NP
N1P3
N1P1
N3P2
N1P1
The main nectar and pollen source and honey flowand dearth periods differ widely
with the latitude, region, season and type of vegetation. The flowering period of even the
same plant species vary in different geographic regions and agroclimatic zones. Some
examples of suitable states/localities, based on the availability of bee pasturages
in India are described below, as bee keeping is only profitable if bee pasturage is
abundantly available in a particular locality.
Himachal Pradesh : The stone fruits including pear, almond, plum, cherry, apple,
apricot, etc. are available in the spring. In the beginning of May,barberry flowers provide
minor honey flow periods followed by soapnut in the end of the June. Early in August,
maize inflorescences provide pollen for brood rearing to bees. The colony strength increases. At the end of August, Plectranthus blossoms appear which continue up to the
end of October (Abrol, 2010).
Jammu & Kashmir : Plectranthus(Shain/Chhichhri), Robinia , fruit trees, Fagopyrum
(buckwheat) are major beeflora in Kashmir region. Dalbergia sissoo (Shisham ), Accacia
modesta ( Phalahi ), Sapindus (Soapnut ), Syzygium ( Jamun),Toon, Robinia, Eucalyptus
(Safeda), fruit trees and Brassicaare major beefloral sources in Jammu region. The
region has long winter dearth period and colonies need to be migrated to plains during
winter.
Punjab : Surplus honey is stored from Eucalyptus, shisham, citrus, stone fruits,
litchi and barseem flowers in March, April and May. Then follows the dearth period up to
September and during this period the bees visit a number of Wild flowers and the blossoms of maize in the end of July. In the oilseed and cotton growing areas bees also
store surplus honey from toria, cotton, arhar etc. in September and October. Punjab has
now attained prime position in beekeeping and honey export. In the recent years area
under bee floral plants is reducing. There is, hence, a strong need to increase cultivated
crop flora and exploit forest flora.
Haryana : The important flora of these States include Brassica, Eucalyptus,
Trifolium alexandrinum (Egyptian clover/ Berseem ), Cajanus cajan L. (pigeon pea),
Shisham, Gossypium hirusutum (American cotton), Ziziphus spp.(Ber) and Helianthus
annuus (Sunflower) etc. Commercial beekeepers from Punjab and J&K migrate their
apiaries to exploit Brassica crops in Hisar and Rewari.
Rajasthan : Brassica spp. are major bee flora. This is a potential area for migratory
beekeeping from Punjab, Haryana, and Himachal Pradesh etc. during Brassica season.
Madhya Pradesh and Chhatisgarh : The region is not good for beekeeping. Some
oil seed (Brassica) growing area adjoining U.P. has some good potential. Some beekeeping with A. cerana is practised. Upcoming area for beekeeping with A. mellifera.
Bihar : The important bee flora in erstwhile Bihar comprises of Lathyrus (Khasari),
Litchi, Madhuca, Egyptian clover, sunflower, maize, Sesamum, Syzygium and Pongamia
(karanj).There is an established pattern of migratory beekeeping between Bihar and
Jharkhand. Beekeeping is successful with migration.
153
Jharkhand : Jharkahand state is known for niger and karanj honey.In forest, trees
like karanj, neem, jamun, mahua, shisham, ber, tamarind,jack fruit etc. are good source
of pollen and nectar and provide continuous food availability almost throughout the year.
In addition to the forest flora, crops viz. , oilseeds (mustard, niger) cruciferous,
cucurbitaceous and unbliferous vegetables are available in abundance. Orchards of
pear, aonla, citrus etc. are also available in the state, for beekeeping.Presently the
state is a hub for migratory beekeeping. Most of the beekeepers from Bihar migrate
their colony on karanj, niger, mustard, jamun& forest flora and harvest rich honey yields.
Karnataka : Carvia, coffee, coconut, Eucalyptus, niger, soapnut, Tamarindus, arjuna,
Syzygium and Bhedas (Eugenia) are major bee flora available in the state. The state has
a good potential for beekeeping.
Orissa : The important bee floras are Coconut and forests trees. Other floras are
niger, Sesamum, sunflower, karanj, Terminalia, Shisham, drum stick, Madhuca, citrus,
cashew, imli , jamun , maize and banana. Orissa is a potential state where good prospects for beekeeping exist.
Andhra Pradesh : The major bee floras are coconut, citrus, mango, cashew, drum
stick, imli, jamun , palmrah, sesamum, sunflower, soapnut,banana, rubber and cotton.
Beekeeping is successful with migration. Good beeflora do exist in Cotton growing districts. Indiscriminate use of insecticides is the main constraint.
Maharashtra : The important beeflora are Jamun, Carvia, Pisa, imli and other fruit
trees. There is moderate potential of beekeeping.
Uttaranchal and Uttar Pradesh : Important bee flora areniger, shisham, Drum stick,
Eucalyptus, jamun, Brassica, Madhuca and some fruit plants. In Dehradun and
Saharanpur, Litchi is the main bee flora. In Muzzaffarnagar, Meerut, Faizabad, Mathura
and Agra, Brasssica spp. are grown extensively. Uttaranchal has high potential areas for
beekeeping. Depletion of bee flora has, however, reduced prospects for beekeeping.
Beekeepers of Punjab have started exploiting Brassica growing belt of Agra and Mathura.
Tamil Nadu : Major bee flora includes Coconut, rubber, imli, cardamom, Coffee,
soapnut, wood apple, nigeretc.October to March is the major honey flow period in this
region.
Kerala : The most important bee floras are Rubber and coconut plantations.
Meliponiculture is being practiced by the people. The State has good beekeeping potential. Good efforts have been made to establish Apis mellifera in the State.
West Bengal : Sunderban and Mangrove forests are potential bee forage areas for
domesticated as well as wild honey bee spp. In addition to forest flora Litchi, Mustard,
Eucalyptus and corriandar are the other important bee flora. Most of the honey in the
State comes from Apis dorsata. There seems to be good potential of beekeeping with
hive bee species ( A. cerana and A. mellifera).
154
Nagaland : Meliponiculture is being practiced by the rural people by traditional
means and there is vast diversity of stingless bees. The honey produced by stingless
bees is in great demand because of its immense medicinal value.Apiculture in the state
is crude and unscientific, though survive with little management. The domesticated bees
are Apis cerana and stingless bee Trigona . Wild honey bees found are rock bee A.dorsata,
little bee A.floreaand, A. laboriosa .
North eastern hills region : It is the most neglected region as far as the development of beekeeping is concerned.
Suggested Readings
Abrol, D. P. 2010. Bee Pasturage. In : Beekeeping : A Comprehensive Guide to Bees
and Beekeeping . Scientific Publishers, Jodhpur. pp. 217-291.
Atwal, A. S.; Bains, S. S. and Singh, S. 1970. Bee flora for four species of Apis at
Ludhiana. Indian J. Ent . 32 (4) : 330-334.
Baker, H. G. and Baker, I. 1975. Studies of nectar-constitution and pollinator plant
coevolution. In : Gilbert L. E., Raven P. H., eds. Coevolution of Animals and
Plants . New York: Columbia University Press, 126-152.
Baker, H. G. and Baker, I. 1983. A brief historical review of the chemistry of floral nectar.
In : Bentley, B, Elias, T.S. eds. The Biology of Nectaries . New York: Columbia
University Press, 126-152.
Balasubramanyam, M. V. and Reddy, C. 2011.Mineral Variations of Honey of Indigenous
Honeybee Species from Western Ghats of Karnataka. Journal of Pharmaceutical Research & Clinical Practice 1 (2) : 36-42.
Deodikar, G. B. and Suryanarayana, M. C. 1977. Pollination in the service of increasing
farm production in India. In : Nair, P. K. K. (ed.) Advances in Pollen Spore
Research . 2 : 60-82.
Herbert, Jr., E. W. and. Shimanuki, H. 1978. Chemical composition and nutritive value
of bee-collected and bee stored pollen. Apidologie 9 : 33-40.
Mishra, R. C. and Kaushik, H. D. 1992. Beeflora and beekeeping maps of India.
Changing villages : Rural News and Views 11 (3) : 88-107.
Partap, U. 1997. Bee Flora of the Hindu Kush Himalayas : Inventory and Management.
International Centre for IntegratedMountain Development (ICIMOD), Kathmandu,
Nepal. 297 p
Southwick, E. E. 1990. Floral nectar. American Bee Journal , 130 : 517-519. ULTURE.
Thakur, M. 2012. Bees as Pollinators - Biodiversity and Conservation. International
Research Journal of Agricultural Science and Soil Science. 2 (1) : 1-7.
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MITES OF HONEYBEES AND THEIR MANAGEMENT
Rachna Gulati
Department of Zoology,
CCS Haryana Agricultural University, Hisar
Honeybees, like all animals, are prey for a wide range of enemies from viruses to
insects and mammals. Amongst these, acarine pests in recent years acted as an important perturbation and have started threatening the long term sustainability of beekeeping. Four species of mites are closely associated with honeybees; three of these are of
economic importance (Acarapis woodi (Rennie), Tropilaelaps clareae Delfinado and Baker,
Varroa destructor Anderson and Trueman) while the fourth is little known (Euvarroa sinhai
Delfinado and Baker). In this technical bulletin biology, nature of spread and
management of parasitic mites of honeybees have been given in details.
The characteristic features of Acari are four pairs of segmented legs (3 pairs in larval
stage) and an unsegmented body comprising gnathosoma and idiosoma, which is in
contrast to the distinctly divided body of insects. Gnathosoma is an anterior region,
which bears mouth and mouthparts. Two pairs of mouthparts are present, one is the
sensory pedipalp and the other is piercing/ cutting chelicerae.
Mites that affect honeybees found in bee hives may be divided into four groups:
parasites, phoretic, scavengers and predators of scavengers. Among these, parasitic
mites are detrimental to honeybees. These are A. woodi (endoparasite) and two
ectoparasites i.e. V. destructor and T. clareae . Phoretic mites like Neocypholaelaps
spp. are flower or leaf feeding mites that use honeybees for transport from one plant to
another and arrive accidentally in beehive. Scavengers are the species that feed on old
provisions and a few species also feed on other mites. Soil mites (cryptostigmata) may
also crawl inside the bee boxes. Astigmatid mites mostly known as store product mites
and or as house dust mites may be encountered in large number. They may be a problem for the bees as they may become painful guest and not a paying guest. They are
likely to feed on pollen and honey. There are some mites that are beneficial as they
control harmful mites. They mostly belong to cheyletidae family.
Morphological Characters
Scavenger mites
These are slow moving globular mites with clear bodies and darker pigmented legs.
The chelicerae form stout pincers and can ingest solid food. The morphological features
associated with this group of mites are :
Acarus : soft cuticle on body, Sigma I is more than three times sigma II. In male on
leg I, femur is highly enlarged and bears a conical part.
Austroglycyphagus : Chelicerae and legs reddish brown in colour, Sigma I and II on
genu of leg I is of same length.
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Carpoglyphus : Morphologically resemble acarids but differ in thick apodemes on
the ventral surface. Length of the adult is 400 µm. Coxal field I totally closed.
Dermatophagoides : Basically house dust mites in which vertical setae are absent
in both sexes. Long terminal setae are present.
Glycyphagus : Comparatively larger (600 µm) than other scavenger mites. Body
setae are branched and exceptionally long, the legs terminate in a long tarsus. Males
do not possess anal suckers. Females are with genital opening at the level of coxa III
and IV or if large at the level of coxa I and II.
Kuzinai : Coxal field II is open but Coxal fields III are widely separated.
Schulzea : Coxal field II is closed but Coxal fields III are widely separated.
Sennertia : Dorsum with single dorsal shield.
Suidasia : Chelicerae and legs reddish brown in colour.
Tyroborus : Spine like setae on the dorsal apex of tarsus I.
Tyrolichus : Lateral setae are 4-6 times longer than dorsal setae.
Tyrophagus : Gnathosoma partially retractile, needle like setae on the dorsal apex
of tarsus I.
Vidia : Coxal fields III are close to each other.
Parasitic mites
T. clareae : Small, elongated, light reddish mite of 1,030 µm length and 550 µm
breadth, dorso-ventrally flattened body, presence of large number of setae on body
surface and claws on legs, pretarsus of legs act as attachment organ, presence of
short, stumpy, curved posterior three pairs of legs and reduced pedipalps.
T. koenigerum : Female body is oval, light brown, dorsal plate weakly sclerotized
covered with numerous short spine like setae and pear shaped anal plate. Length and
width of female body is 684-713 µm and 433- 456 µm whereas in case of males the
values are 570 and 364 µm, respectively.
V. jacobsoni : Comparatively broader (1.5 mm breadth) than T. clareae and 1.0 mm
in length, easily visible as flattened red/brown elliptical dots. In females, each tarsus is
modified into lobed sucker and presence of stiff hairs on ventral side, which entangles
with hairy bees. Male is smaller, paler and less sclerotized than female. Male chelicerae
are modified for sperm transfer.
V. destructor : reddish-brown, easily visible as flattened red/ brown elliptical dots. It
is about 1.1 mm long and 1.7 mm broad and visible to the naked eye. Adult males are
smaller and are yellowish-white. Both sexes have eight legs. In females, each tarsus
(anterior portion of leg) is modified into lobed sucker. Male chelicerae are modified for
sperm transfer. Stiff hairs are present on the ventral side of mite body
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V. underwoodi : It is a ellipsoidal, light chestnut brown mite. It closely resembles
V. jacobsoni except that it is much smaller in size. Adult female is about 760 µm long
and 1,160µm wide. Male is round in shape, weakly sclerotized with light tanning on legs
and setae.
Euvarroa sinhai : Adult female is brown, pear shaped, 1,040 µm long and 1,000µm
wide, absence of fixed cheliceral digit. Male is smaller than female, pale coloured and
its chelicerae are modified for sperm transfer so it is not able to feed.
Acarapis woodi : Tiny mites, chelicerae are modified to form sucking stylets that
are used to pierce the cuticle of adult bees and suck blood.
A. externus : In female, posterior margin of coxa IV is not bilobed.
A.dorsalis : In female, posterior margin of coxa IV is bilobed.
Pyemotes : They are milky white, spindle shaped and rounded segmented mites.
Female possess pseudo stigmatic organs. Leg IV of female with pretarsus, claw but
without apical whip like setae, idiosoma is elongated, gravid female with sac like
hysterosoma.
Phoretic mites
Neocypholaelaps indica : Minute mites with 0.47 mm broad and 0.63 mm long
idiosoma.
Predatory mites
Chelytidae is the main family associated with honeybee hive. They are white, yellow
or orange colour mites with bulky mouth parts, pedipalps end with strong horn/ claw,
presence of comb and sickle like setae. Chelicerae and rostrum fused into a cone,
peritremes arched or forming an M-shaped configuration.
Acaropsis sollers : Pedipalp tarsus with one comb and three smooth setae.
Cheyletus : No fan shaped anal setae, few dorso-median setae, setae on margin of
dorsal plate fusiform or spatulate
Varroa spp.
Varroa destructor Anderson and Trueman, an ectoparasitic mite of brood and adult
bees, is a serious pest of Apis mellifera L. It belongs to order mesostigmata and family
varroidae. Varroa mite has been found on flower feeding-insects Bombus pennsylvanicus
(Hymenoptera : Apidae), Palpada vinetorum (Diptera : Syrphidae), and Phanaeus vindex
(Coleoptera: Scarabaeidae). Although the Varroa mite cannot reproduce on other
insects, its presence on them may be a means by which it spreads short distances.
Among the bees that serve as hosts of the Varroa mite are Apis cerana, A.
koshchevnikovi, A. mellifera mellifera, A. m. capenis, A. m. carnica, A. m. iberica, A.
m. intermissa, A. m. ligustica, A. m. macedonica, A. m. meda, A. m. scutellata, and A.
m. syriaca .
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Varroa mite infested A. mellifera was subsequently transported around the world
via quarantine incursions and normal practice of shipping live bees between countries
(Anonymous, 2006). Unfortunately, Varroa mite proved more virulent to its new host and
subsequent research revealed that genus Varroa consists of at least four but possibly
seven distinct species. Among the four recognized species, the most destructive and
largest among these is Varroa destructor (Anderson and Trueman, 2000) followed by
V. jacobsoni, V. rindereri and V. underwoodi . These species are morphologically
distinct and show clear differences in their mitochondrial DNA sequences. They are
reproductively isolated and show differences in their host specificity and geographical
distribution. In this sense, A. koshchevnikovi is parasitized by V. rindereri and A. cerana
by V. underwoodi, V. jacobsoni and V. destructor in Asia but A. mellifera is only
parasitized by V. destructor worldwide. Two mitochondrial haplotypes, Korean (K) and
Japanese (J) of V. destructor are capable of reproducing on A. mellifera but vary in their
virulence with K type assumed to be more virulent.
V. destructor has spread all over the world except Australia and central Africa
causing severe losses of feral honeybee populations in USA and worldwide. In India, it is
reported to cause 30-40 per cent loss in A. mellifera colonies. It has ravaged A. mellifera
colonies from Jammu and Kashmir, Himachal Pradesh, Punjab, Haryana, Delhi, Rajasthan,
Uttar Pradesh and Uttaranchal and is fast approaching Bihar and West Bengal (Chhuneja,
2008). In the last three years, beekeeping in Haryana is adversely affected by this mite.
In the present scenario, 90 per cent apiaries and 50 per cent colonies are affected by
this mite (Gulati et al. , 2009).
V. destructor feed upon haemolymph of adult and immature bees during phoretic and
reproductive life stages. It generally lives for seven days to thirteen days on adult bees.
V. destructor has direct impact on developing and adult bees, resulting in lowered body
weights and reduced longevity. These impacts translate into both lowered productivity
and higher mortality at the colony level. In addition to colony loss, reduced honey
production and a decrease in pollination efficiency as a consequence of V. destructor
parasitism has also been observed. It is also known to be associated with honeybee
pathogens and are confirmed to be vectors of diseases. Several experimental studies
indicate that mites transfer single stranded RNA viruses between bees such as to
transmit Hafnia alvei and Serratia marcescens , which cause Haffnosis and Septicemia,
respectively, in bees.
Asian mite ( Tropilaelaps spp.)
They are serious parasitic mites affecting both developing brood and adult honeybees. Parasitization by these mites can cause abnormal brood development, death of
both brood and bees, leading to colony decline and collapse, and can cause the bees to
abscond from the hive. The natural host of this mite is the giant Asian honeybee, Apis
dorsata , but T. clareae can readily infest colonies of the Western honeybee, A. mellifera.
It is also associated with other Asian honeybees, including Apis laboriosa, A. cerana
and A. florea. T. koenigerum was reported as a new species of parasite infesting Apis
dorsata in Sri Lanka. It has also been found in association with A. laboriosa, A. cerana
and A. mellifera in Kashmir, and was recently detected in Nepal, Borneo and Thailand.
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The life cycle and parasitism of A. mellifera by Tropilaelaps is similar to that of V.
destructor although there are slight differences. Tropilaelaps has a higher reproductive
rate than varroa as it has a shorter life cycle. This is because they have a faster
development time and a shorter phoretic phase (non-reproductive transport phase, time
spent on the adult bees) between reproductive cycles. Consequently, when both types
of mite are present in the same colony Tropilaelaps populations build up far more rapidly
than varroa, by a factor of 25:1 in favour of Tropilaelaps . Adult mites enter cells containing larvae where reproduction takes place within sealed brood cells, particularly those of
drones. The mites can reproduce in both worker and drone cells, but as with varroa there
is a preference for drone brood, but this is not as marked. Typically, the mother mite
lays three to four eggs on mature bee larvae 48 hours after cell capping, about one day
apart. The eggs hatch after around twelve hours, then the larva goes through nymphal
stages (protonymph, deutonymph) before reaching the adult stage. Once hatched, all
stages of both female and male mites feed on the haemolymph (blood) of the developing
bee, causing damage through feeding by depriving the developing bee of essential nourishment required for growth.
Development from egg laying to the adult stage takes approximately 6 days. When
the adult bee emerges, both adult male and female mites and the original invading mother
mite exit the cell to search for new hosts. Up to 14 adult mites and 10 nymphal stages
of mite have been recorded in a single cell. With varroa infestations, immature females
and the male mites die in the cell. Unlike the varroa mite, Tropilaelaps cannot feed on
adult bees because its mouthparts are unable to pierce the body wall membrane of the
bees. The mites depend on the developing brood for food, and move from the adult bees
to feed on the larvae as quickly as possible after emergence, so the phoretic stage is
much shorter than that of varroa, and may only be between 1-2 days. Gravid female
mites (carrying eggs) will die within two days unless they deposit their eggs. Tropilaelaps
is therefore less well adapted for survival in hives where there are long broodless
periods.
The harmful effects of Tropilaelaps infestation
The following harmful effect has been observed in the honeybee colonies: reduction
in life span of adult bees emerged through parasitization in brood stage, signs of
physical/physiological damage in adult bees such as lower body weight, shrunken and
deformed wings and legs, Irregular and poor brood patterns with patches of neglected
brood and perforated capping, In severe infestation up to 50% developing brood may die
and colonies may abscond.
Tracheal mite, Acarapis woodi Rennie
Acarapis woodi is the only endoparasite obligate mite that infests Apis mellifera and
Apis cerana indica honeybees. Apis dorsata and A. florea are not reported as its host
as yet. Acarapis woodi previously known as Tarsonnemus woodi was firstly recorded by
Rennie et al ., in 1921. This mite infects the tracheal system of adult bees, queen,
workers and drones being equally susceptible. This mite does not affect the brood.
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Presently this mite is reported from all over the world. In India it was first confirmed
parasitizing A. cerana indica colonies by Singh (1957). After introduction of Apis mellifera
in India, transmission of A. woodi from India honeybee to A. mellifera reported by Adlakha
(1976) from northern states.
Acarapis woodi enters the respiratory tract of honeybees when they are very young.
They multiply inside the respiratory pipe lines. If the population of mite is high, the
respiratory tract of bee gets full with mite, mite excreta, moulting case and dead bodies.
This creates problem of respiration for the affected bee. The bee suffers from lack of
supply of oxygen just like asthama in man. The seriously infested bee is no more in a
position to go out and collect pollen or nectar or do any other form of work. Besides A.
woodi, there are two more species of the genus Acarapis viz., Acarapis dorsalis and
Acarapis externus , both these are external parasite. Former is also known as 'neck
mite' and reported to cause wing less or malfunction. These mites are found only in the
area where the head and thorax join. Acarapis dorsalis causes very little damage and
lives on the thorax in a groove between mesoscutum and mesoscutellum. It may also
found at base of the wings and on the propodenum and the fore pest of the abdomen.
Adult female mites enter into the tracheae of the worker bees within 24 hours after
they emerge from bee brood cells. Single female mite lays 5 to 7 eggs after 3 or 4 days
which hatch after 3 or 4 days. The males emerge on the 11th or 12th day and the
females on 14th or 15th day. Infestation from one adult honeybee to another spreads
when a mite leaves the bee via the first thoracic, spiracle, it climbs a hair, usually on the
thorax, and clings near its tip with one or both hind legs. It grasps a hair of another bee
with its fore legs brushing past descends to the surface of the new bee body.
Mean of spread/Dispersal of mites
The disease can be carried to healthy colony by robbing, drifting and in advertently
transfer of diseased bees to a healthy colony. The thoracic tracheal which lead from the
first thoracic spiracles are the main duct for air in the thorax of honeybees. Numerous
mites in these ducts would partially suffocate the bee and at least impair its ability to
fly, because oxygen is supplied to the flight muscles in the thorax by these ducts.
Initial field signs
These are no specific outward signs of Acarapis woodi infestation. When the
infestation is low, external symptom are not noticeable but in the heavily infested
colonies of honeybees below mentioned systems can be seen :
1. Large number of crawling bees can be seen in front of the infested colony, climbing
on the grass stems. These crawlers are young bees fall on the ground when they
make orientation flight in the afternoon of the day.
2. Infested bees' abdomens may be distended, and the wings often have a dislocated
appearance with the hind wing held at an abnormal angle to the body in a 'K'
configuration.
3. Yellow droppings may appear in some cases on hive parts and in front of the hive.
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4. Bess have distanged and shining abdomen.
5. Bees become sluggish and paralytic and not cover the brood in the normal manner
and formed scattered clusters.
6. Hive population number dwindle.
Euvarroa sinhai Delfinado and Baker
Euvarroa sinhai was first described as an ectoparasite of Apis florea from India by
Delfinado and baker (1974). Two years later it was reported for the first time from
Thailand by Akratanakul and Burgett (1976) who observed that E. sinhai parasitize only
the drone brood of A. florea Kapil and Agarwal (1987) reported this mite from Haryana
and observed its presence on adults and drone brood.
Its life cycle is similar to that of V. jacobsoni except that the mite attack only drones
brood. This is attributed to the fact that the drones have longer developmental period.
The adult male mite has chelicereae modified for sperm transfer, and it is not able to
feed. The adult female leaves the cells and they are able to take haemolynph from the
adult bee. Males, nymphs and eggs are observed only inside the scaled drone brood
cell, adult females are found on adult worker bees. Peak period of reproduction was
March-April and September. There is a non-reproductive peaks. During the non-reproductive phase, the female adults survive on adult workers bees only.
Parasitic mite syndrome
Parasitic mite syndrome (PMS) is a condition of honeybees identified in the USA.
PMS has been identified in bee colonies infested with varroa mite and/or tracheal mite.
It is thought to be caused by a secondary infection as a result of the mite infestation. No
known pathogen has been found to be predominant.
Characteristics
1. Symptoms resembling American foulbrood, European foulbrood and/or sacbrood
diseases may be present-often the symptoms observed are not exactly characteristic of the diseases mentioned.
2. In all cases, varroa and/or tracheal mites are present.
3. A reduction in bee population numbers, crawling adult bees and a patchy brood
pattern is seen. Affected brood are aged from 'C' shaped larvae through to the
prepupal (capped) stage. Larvae may be twisted in their cells, light brown in colour.
Scales are present and are easily removed from the cells. No odour is evident.
Diagnosis/detection mites in the hives
Besides the symptamatology, following methods are used to detect the mite in the hive :
1. Examination of hive debris: A thick white sheet is placed on the bottom board and
taken out after two days. The presence of mites could be seen through naked eyes
or under microscope.
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2. Examination of adult bees: About 200 bees are collected in a wire net from combs
preferable with unsealed brood and dipped in solution, hot water or alcohol. The
bees in the wire net are shaken vigorously so that mites may fall off. These can be
collected at bottom of the container and examined.
3. Examination of brood: Sealed brood cells are uncapped and each pupa and cell after
removing the pupa is examined. The mites can be easily recognized on worker
pupae after 13 days and drone pupae after 18 days of egg lays.
4. Chemical diagnosis: this method in followed when there is no this case acaridae in
used. The bottom brood is covered with water paper and acaridae treatment is given.
Due to the acarided effect mites would be killed and fall on the paper. The dead
mites can be examined under naked eye/under microscope.
Harmful mite population threshold
There is no clear harmful threshold at which a mite population suddenly causes
harm. A mite population that causes no obvious damage to one colony may prove very
damaging to another. This can be due in part to differences in the levels and types of bee
viruses and other pathogens present in the colonies and the bees' natural ability to
tolerate varroa, as well as environmental factors. However, researchers agree that it is
wise to aim to keep the varroa population below 1000 mites as above this level the risk
of damage from the mites, associated pathogens and the effect of feeding on the bees
can quickly become very significant.
Mite invasion pressure
The movement of mites between colonies, spread by adult bees, can play a key role
in the mite population build-up. It can occur at any time of the year when bees are
active. In areas of high colony density with heavily infested colonies, the rate of mite
invasion can be extremely high, and populations may build up to damaging levels in a
short time - sometimes in a matter of a few weeks or months. Varroa populations in
infested colonies increase naturally through two processes - the reproduction of mites in
brood cells, and the influx of new mites into the colony through invasion. Varroa mites
are mobile and can readily move between bees and within the hive. However, to travel
between colonies they depend upon adult bees for transport through the natural
processes of drifting, robbing, and swarming. Varroa can spread slowly over long
distances in this way. However, the movement of infested colonies by beekeepers is the
principle means of spread over long distances.
Management Practices
Several control measures are reported in literature which includes use of organic
acids (formic acid, oxalic acid and lactic acid), chemicals and many vegetable oils.
Environmentally safe chemicals, e.g. formic, oxalic and lactic acid can be successfully
applied to control Varroa . Formic acid 65% (300 ml) of was found 95 per cent effective
which kills mites on the adult bees as well as in the sealed brood cells. Formic
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acid occurs naturally in honey but application for mite control may increase its
concentration. In addition, formic acid treatment of colonies may damage uncapped
brood, young bees and may cause the losses of queens.
Oxalic acid (2-3%) when applied as spraying or trickling in the form of sugar solution
was 90 per cent effective (Charriere and Imdorf, 2002). Lactic acid is weak acid than
formic and oxalic acid and leaves less residues but its efficacy is also less. It exists in
small amounts naturally in honey. Its effectivity was evaluated by many workers but it
varies with concentration applied in the hive. Synthetic chemicals, although most
effective and reliable as they provide immediate relief but cannot be used in organic
honey production because of high residue levels in honey and problem of development of
resistance in Varroa . Therefore, attention is diverted for other alternatives such as
destruction of drone brood either by heating or freezing, caging of queen, use of botanicals, bio-control agents, etc.
Mites trappe, inside the brood cells can easily be removed from a colony by heat or
freezing treatment. Because Varroa prefer drones, combs of drone brood are used to
attract and trap the mites. The mites are then removed by cutting out drone brood. The
mite succumbs around 46-48°C, whereas sealed brood survives. Using a combination of
heat and lactic acid treatment, mite numbers are reduced considerably. It is reported
that heat treatment is much more effective when combined with oil of wintergreen. Mites
in brood cells failed to reproduce or were killed when they were exposed to 40°C for 24
h or to 42°C for 18 h. Workers recommended controlling mites by heating combs of
capped brood without adult bees. However, according to some workers, heat treatment
is a risky procedure that can kill bees. The Russian technique recommended a low
humidity of less than 20 per cent reduces the mortality of bees.
In 'queen arrest method', the queen is temporarily confined to a single brood frame or
portion. This method is labour intensive, slows down colony development and may only
be suitable for the dedicated, small time beekeeper. Caging the queen of A. cerana for
35 to 40 days and separating the brood frames helped interrupt the brood/mite cycle.
Worker brood can also be removed to lower the mite infestation level in the colony.
Screen floors have also been employed by various workers to reduce Varroa
population in hive and brood. Use of screen floors exerts a modest restraint on mite
population growth. In screen used hives, increased brood production and adult bee population are reported as compared in hives with wooden bottom board hives. Partial control
in lightly infested apiaries can be obtained with tobacco smoke or smoke from other
plant materials that cause mite knockdown. Smoke dislodges mites and can be used
periodically to remove emerging mites from brood cells. A sticky board used in conjunction with smoke traps mites provide effective control.
Many chemicals are applied as dusts for managing Varroa populations in A. mellifera
hives. Sulphur dusting is commonly applied in India to control parasitic mites in A.
mellifera colonies in India. Application of powdered sugar dusting resulted in 76.7 to
92.9 percent mite fall.
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Another approach is the use of volatile plant essential oils to control bee mites.
Some botanicals found effective against V. destructor are neem oil, vegetable oil,
mineral oil, thymol oil and canola oil. Neem (5%), thymol (4.8 g thymol/l in 20% canola
oil solution) and canola (20% solution) demonstrated 60-90 per cent effectivity against
Varroa. Neem also inhibits growth of bacterial honey bee pathogens such as American
Foul Brood. Plant oils are complex compounds that may have unwanted side effects on
bees and beekeepers and could contaminate hive products.
Suppressed mite reproduction (SMR) or Varroa Sensitive Hygiene is a trait of honey
bees that provides resistance. Some beekeepers let all susceptible colonies die and
then rear queens from the survivors to head new colonies. Untreated Africanized
colonies were maintained in Arizona for several years with few tracheal and Varroa mites.
Hygienic activity like removal of dead or dying bee reduces the mite levels in untreated
colonies, which require less chemical treatment to manage Varroa .
Defensive behaviors against Varroa in races of A. cerana were studied and grooming
is an important component in mite reduction but it is highly variable in A. mellifera. Bees
remove mites from each other and some even kill them using their mandibles but this
trait may not be heritable in some European bee stock.
The pupal period influences the number of mites completing development. If this
time is shortened, it will lead to fewer Varroa reaching maturity. If the capped cell stage
is reduced by only six hours, fewer immature mites will become adults. Two African bee
races have a heritable (worker) post capping period of only 10 days, whereas European
races require 11 to 12 days. Some researchers suggest climate plays a more important
role in influencing the Varroa population but it is difficult to maintain in A. mellifera
colonies in northern hilly regions of India.
While long-range, non-chemical controls are vigorously being sought, beekeepers
need immediate relief from existing mite infestations. Fluvalinate (99% effective),
Flumethrin (95% effective), Cymiazole, Coumaphos, Bromoprophylate and Amitraz (99%
effective) are used in some parts of world for effective V. destructor control. The
chemicals are applied as pesticide-impregnated plastic strips, which are hung between
frames of bees in a hive. Applied in this manner, it is released slowly and dispersed by
adult bees. Among these, Cymiazole, Coumaphos and Bromoprophylate are effective in
brood less condition. These chemical options for Varroa pose a serious problem
because repeated exposure to the same pesticides select for resistant mites.
Reports of fluvalinate/Coumaphos/Amritraz-resistant mites have surfaced in many
other parts of world. The resistance crisis is being compounded by contamination of hive
products including honey, wax and propolis. In addition, drone survival is found to be
lower in colonies treated with fluvalinate, which may also affect their mating ability.
Biological control agents of mites are used to kill them whilst sparing desirable
organisms. In a laboratory bioassay, the susceptibility of Varroa mites was measured to
infection by of forty isolates of fungi from six genera (Beauveria, Hirsutella, Paecilomyces,
Metarhizium, Tolypocladium, Lecanicillium ) at 25 oC and high humidity (> 95% RH).
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A strain of the fungus Metarhizium anisopliae was found as effective as fluvalinate against
Varroa. This fungus is safe to honeybees and found no effect on queen's production. It is
effective even 42 days after application.
With effective and proper detection and management techniques in place, the
menace of V. destructor is regulated effectively in many parts of the country. However,
there is a dire need to aware the beekeepers about hive hygiene and negative effects of
use of persistent chemicals and their higher doses. Right method of application and
time of application are also important in controlling the mite infestation effectively in A.
mellifera colonies.
Suggested Readings
Anderson D. L. and Trueman J. W. H. 2000. Varroa jacobsoni (Acari : Varroidae) is
more then one species. Experimental and Applied Acarology , 24 : 165-189.
Charriere J. D. and Imdorf A. 2002. Oxalic acid treatment by trickling against Varroa
destructor, recommendation for use in central Europe and under temperate
climate conditions. Bee world , 83 (2) : 51-60.
Chhuneja P. 2008. Varroa destructor Anderson and Trueman and strategies for its management in Apis mellifera L. colonies. In : Pest Management in Global ContextSouvenir, 2nd Congress on Insect Science, PAU, Ludhiana . 48-58 pp.
Gulati R, Sharma S. K. and Saini R. K. 2009. Varroa , enemy of honeybees : Its effect,
life cycle and control. Tech. Bull. , Dept of Entomology, CCS HAU, Hisar. 24 pp.
166
INSECT POLLINATORS' DISEASES AND THEIR MANAGEMENT
B. S. Rana, M. L. Khan and Sapna Katna
Department of Entomology and Apiculture,
Dr Y.S. Parmar University of Horticulture and Forestry, Nauni-Solan (HP) 173 230
In insect pollinators, diseases are caused by incidence of viruses, bacteria, fungi
and protozoa. Among the insect pollinators, honey bees are the most important and
efficient pollinators. Due to the presence of brood, adults, honey, pollen and wax in the
colonies/nests, they are very attractive to pathogens and enemies. Additionally, their
trophyllaxis, absconding, swarming, robbing, drifting, foraging and shifting/migration,
etc. (Nauman et al., 1991). Behavioural characteristics help in very easy and fast spread
of the diseases or pathogens within a colony, colony to colony and place to place. A lot
of work has been done on the diseases of honey bee pollinators however, little is known
about this aspect of other insect pollinators. Therefore, in this chapter important diseases of honey bee pollinators are discussed.
1. Thai Sacbrood Virus Disease
Thai sacbrood virus (TSBV) causes diseases in Apis cerana F., was first recorded in
Thailand in 1976 (Bailey et al., 1982, Journal of Invertebrate Pathology 39 : 264-265)
from where it spreaded to Burma, Nepal, India and Pakistan. In India, it was noticed in
Meghalaya in 1978 (Kshirsagar et al., 1981) and later spreaded to remaining part of the
country. TSBV is the most destructive to A. cerana as it killed 95% of the colonies
(Phadke and Wakhle, 1996). Presently its incidence is negligible in the country.
Causative organism : The causative virus is isometric in shape with 30 nm diameter and has a single stranded RNA of 2.8 x 10 6 daltons molecular weight. It sediments
at 150 S in 0.01 M phosphate buffer or 160 S in 0.1 M KCl. It produces 3 close but well
defined bands of proteins with molecular weights 30,200, 34,000 and 38,700 with 1.351
+ 0.002 g/ml buoyant density in CsCl (Bailey et al., 1982). It loses infectivity within six
months of storage even at -20 oC.
Spread : In the colony, young adult bees take inoculum during exchanging food,
feeding brood and cleaning the dead brood. TSBV get accumulates and multiplies in
hypopharyngeal glands of the bees which act as continuous source of infection through
royal jelly feeding to 2-5 day old larvae but death occurs at prepupal stage. Colony to
colony or apiary to apiary, TSBV spreads through robbing, drifting, absconding, manipulation and migration. It also spreads from the queen to brood through eggs.
Effect of infection on brood : TSBV disturbs the moulting and development of
brood which stops casting of skin. A greyish granular exuvial fluid containing the virus
particles fills the space between body of dead prepupae and loosely attached skin which
appears 'sac' like.
Effect of infection in adults : Infected worker bees live for only 3 weeks and eat
little pollen due to reduction in metabolic activity. The foragers collect less pollen. TSBV
167
Different Vespine species predating upon Honey Bees Apis mellifera L. in Jammu region
(A) Vespa orientalis L.
(Yellow banded brown wasp)
(B) Vespa velutina (= auraria ) S.
(Golden wasp)
(D) Vespa tropica
(= cincuta) Leafmansi
Yellow banded black wask
(C) Vespa basakis
Smith black wasp
(E) Vespa mendamiria (=
magnifica)
Smith Large wasp
Picus domesticus
Merops orientalis
Nectarina asiatica
Different Vespine species predating upon Honey Bees Apis mellifera L. in Jammu region
(A) V. velutina nest on bough on tree
(Polyethic period)
(B) V. velutina nest under the eaves
(Polyethic period)
(C) Antirior view of V. velutina nest
(Envelope removed)
(D) Combs and pillars of V. velutina nest
(Envelope removed)
(D) Predation of A. melafira by
V. mandarinia wasp
(E) Dead A. melafira bees after group
predation by V. mandarinia
Adult stage of Greater wax moth
Larval and pupal stage of Greater wax moth
Adult stage of Lesser Wax moth
Larval and pupal stage of Lesser wax moth
Damage caused by Greater wax moth
in Apis dorsata comb
Damage caused by Greater wax moth
in Apis cerana indica comb
multiplies in brain, fat bodies, hypopharyngeal glands, muscles and tracheal end cells
of worker, drone and queen bees.
Field diagnosis
Colonies with scattered and perforated brood.
Brood mortality occurs in prepupal stage.
Dead prepupa lies straight with tongue like projection of the head in perforated cell..
Dead brood emits no peculiar odour.
Sac-like appearance of the dead prepupae which can not be drawn to rope.
Brood colour changes from white to yellow, brown and finally black. Then dries down
to a soft boat shaped scales in the cells.
Colonies show reduced brood rearing, foraging and cleanliness activities which results in weakening of the colonies.
A. cerana colonies show high tendency to abscond than A. mellifera. In severe stage
of infection, 2-3 colonies come together and form a single colony by killing the queens.
Pathogenicity : Feed TSBV or extract of diseased brood in sugar syrup (50%) to
healthy A. cerana colonies and observe the appearance of typical disease symptoms.
2. Sacbrood Virus
Sacbrood virus (SBV) disease is widely reported from A. mellifera L. but is not serious like TSBV. It was noticed for the first time in 1913 from USA (White, 1913) and 1998
from India (Chandel et al., 1999). It is similar to TSBV of A. cerana but it differs in
following physico-chemical properties.
Physical properties : SBV sediments at 160s in phosphate buffer and produces
one broad band of molecular weight range 29,000 to 34,000. Its buoyant density is 1.352
+ 0.001 g/ml in CsCl, pH 7. Remains viable at room temperature for 10 days in purified
brood, three weeks in dry form, 20-25 days in hives and very long in freeze dried
condition but destroy in 10 min at 58oC.
Serological relation between SBV and TSBV
Serologically, SBV and TSBV are closely related strains but in the field restrict their
infectivities to respective bee species.
They also show variation by forming spur in gel tests when either of the specific
antiserum is used against them. Thus TSBV is a virulent variant of SBV.
Now reverse transcriptase polymerase chain reaction (RT-PCR) technique is in use
for their molecular level detection.
RT-PCR studies can be done by using primers designed by Grabensteiner et al. ,
2001 and Rana et al. , 2007).
Management of TSBV and SBV : There is no specific and control measure for
TSBV and SBV because virus becomes part of the host cell. However, following measures can help in minimizing the possibilities of further spread of the disease :
168
Keep colonies strong and exercise check on robbing, absconding, drifting and
exchange of combs and equipment.
Adopt general colony hygience like frequent cleanliness of hives, handling of diseased and healthy colonies separately during manipulation, honey extraction, etc.
Avoid hiving stray swarms.
Isolate healthy colonies from infected ones.
Create broodlessness in colony by caging queen for 15 days.
Check the colonies periodically for any abnormality.
Destroy the severely infected colonies and combs.
Multiply disease resistant colonies.
Replace queens from diseased colonies with newly mated ones.
Disinfect empty equipment and combs by soaking in a detergent (surf excel, 1%)
solution containing 1% formaline for few hours. Then wash them with fresh water, dry
and use.
or
Disinfect the empty and dry combs with UV- rays each side for 20 min in protected
chamber.
Feed a dose of oxytetracyclin or ciprofloxacin @ 200 mg (5% a.i., vet. grade) per
colony in sugar syrup (50%) to prevent secondary infection.
3. Apis Iridescent Virus (AIV)
This virus is associated with 'Clustering disease' of A. cerana adult bees which was
first reported from Kashmir and other parts of northern India in 1975 (Kshirsagar et al.,
1975). It can multiply in A. mellifera also.
Target tissues : It multiplies in fat bodies, alimentary tract, hypopharyngeal glands
and ovaries of adult bees. It is more prevalent during hot months. Presently AIV is not
prevalent in India.
Spread : Its transmission is through faeces, eggs, gland secretions of infected
bees and even by ectoparasites.
Causative virus : AIV forms crystalline masses in purified form or in host tissues. It
appears blue violet or green on illumination with bright white light. Infected tissues (fresh
and unfixed) can be easily seen under light microscope.
AIV is a DNA virus with 150 nm diameter. It sediments at 2216 S and has a 1.32 g/
ml buoyant density in CsCl.
Field diagnosis
1. Infected bees form cluster initially inside and later outside the hive walls, especially
during summer. The cluster is compact and bees are not active.
2. Crawling bees are also found on the ground.
3. Foraging, egg laying and brood rearing activities are nearly stopped.
4. Infected colonies perish within 2 months.
169
Detection in laboratory : Dissect the fresh infected worker bees in water under
microscope. Illuminate the tissues from above with an oblique intense white bean. AIV
containing tissues appear blue violet or green while healthy tissues give creamy white
appearance.
Pathogenicity : Feed purified AIV or extract of the infected bees in sugar, syrup to
A. cerana colonies. Pathogenicity can be checked by injecting AIV in PB or saline to
pupae.
Like TSBV and SBV, confirmation of AIV is done through electron microscopy,
immunodiffusion gel tests and ELISA test.
Management of AIV
Isolate healthy colonies from diseased one. Migrate disease colonies to colder areas.
Maintain general colony hygiene.
Keep colonies strong by providing food, bees, brood combs, uniting weak colonies
and keeping newly mated young queen.
Prevent robbing, drifting and absconding.
Destroy severely infected colonies.
Multiply disease resistant stock.
4. Kasmir Bee Virus
Kashmir bee virus (KBV) disease was reported for the first time in A. cerana adult
bees from Kashmir and other parts of India in 1977 (Bhambure and Kshirsagar, 1978).
Different strains have also bee reported in A. mellifera from Australia and other countries. KBV multiplies quickly and abundantly in the adults of both the hive bees. At
present, it is not known in any of the hive bees in India.
Spread : KBV spreads through nursing, cleaning, robbing, manipulation, drifting
and absconding behavioural activities.
Causative virus : KBV is 30 nm in diameter with isometric shape. It is a RNA virus
and sediments at 172S. It has a buoyant density of 1.371 g/ml is CsCl and three unstable proteins (molecular weights : 24,000, 37,000 and 41,000). It can be found in
association with AIV.
Field detection
Appearance of crawling bees in front of the hive.
Presence of trembling and irregular moving bees in circles near the hives.
Death of appreciable number of bees during December and January.
Bees form cluster outside the hive.
Death of bees occurs within one week.
Pathogenicity : Inject or rub KBV on the bodies of adults of either of the hive bees.
Infected bees die within 6 days.
Confirmation is done through electron microscopy, immunodiffusion gel and ELISA tests.
170
Management
Destroy the diseased colonies.
Check drifting, robbing and absconding.
Bacterial diseases
In honeybees, two most important and widely distributed bacterial diseases such as
'American foul brood' and 'European foul brood' are well known.
5. American Foul Brood Disease
American foul brood (AFB) disease is one of the most dreaded and highly contagious diseases of A. mellifera brood in the world (Bailey, 1981). However, in tropical
Asia, where sunlight is abundant and temperature is relatively high throughout the year,
it seldom causes severe damage to beekeeping industry. If unchecked, it can kill a
colony and spread to other colonies in the apiary nearby. It was reported for the first
time in A. mellifera from America in 1907. It has not been reported from India except in
1962 on A. cerana .
Causal organism : The disease is caused by a rod shaped (2.5-5.0 X 0.5-0.8 µm),
peritrichous flagellate, spore forming and gram positive bacterium, Paenibacillus larvae.
It forms oval endospores of about 1.3 X 0.6µm size which are resistant to heat, chemical
disinfectants and desiccation. These remain viable indefinitely on beekeeping equipment, so the disease is usually diagnosed during the active brood rearing season. The
spores can remain dormant for years (upto 35).
Spread : Infection spreads within the colony from adults to brood and vice-versa by
the bees engaged in cleaning combs and nursing brood activities. It spreads from colony
to colony and other apiaries through robbing, drifting, absconding, manipulation and
migration.
Field diagnosis
Irregular pattern of sealed and unsealed brood.
Perforation in sealed brood.
Colour of the brood changes from pearly white to dark brown and finally black.
Death of brood at prepupal stage.
Dead brood lies upright with their heads pointing outwards.
Brood cappings appear initially discoloured, moist, sunken and finally dark in colour.
Decaying brood emits rotten flesh like odour.
Finally the brood dries down to a brittle scale which adheres tightly to a cell wall.
The scale exhibits a pupal tongue which protrudes upwards.
The body of decaying larva if picked up with the help of a tooth-prick stretches into a
rope of 2-3 cm. This ropiness test is typical to AFB.
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Laboratory diagnosis
Dry scales produce strong fluorescence in ultra violet light.
Holst milk test : Suspend a suspected scale, or a smear of diseased larva,
in a tube with 3-4 ml of 1 per cent powdered skimmed milk in water. Incubate at 37 O C.
Presence of P. larvae spores, clears the suspension in 10-20 minutes due to the presence of proteolytic enzymes.
Modified hanging drop test : Prepare a bacterial smear from scale or diseased
larva on a cover slip Dry the smear, fix by gentle heating and stain with carbol fuchsin or
a suitable spore stain for 30 seconds. Remove the excess stain by washing with water;
invert the wet cover slip with smear side down on to a droplet of oil on a standard microscope slide. Blot the slide to dry and examine under a microscope using the oil immersion lens (100X). In the areas where oil droplets form pockets of water, the spores of P.
larvae exhibit Brownian movement. Occasionally, some of the Bacillus spores can exhibit such motion, which differ from AFB in size.
Multiplication : Larvae receive infection by swallowing spores with their contaminated food. 24 hrs old larva is more susceptible to infection. Vegetative cells are not
infective. The spores germinate to the vegetative form about one day after entering the
larval gut (anaerobic conditions). Only after penetration to the haemolymph, the cells
start multiplying. The multiplication of the cells in the gut wall only takes place when the
age of the larva is about 10 days (aerobic conditions). Heavy infestation and death of
larva occurs at the age of 13-14 days due to septicemic condition.
Control
Keep colonies strong with good egg laying queens.
Isolate healthy colonies from diseased ones.
Maintain colony hygiene. Prevent robbing, absconding, migration and drifting of bees.
Select and multiply diseased resistant colonies.
Kill the heavily infested colonies with about half pint of petrol by pouring in the top of
the closed hive. Burn these alongwith brood combs in a pit (45 cm deep and wide
enough) and afterwards fill it with soil. Remove the debris by scratching bottom
boards, hive bodies, inner covers or outer covers, collect and burn in a pit. Flame the
hives and equipments with blow torch.
Disinfect the hives, combs and equipment with ethylene oxide (1 g/ lit) for 48 hours
at 430C in fumigation chamber. Reuse the material after proper aeration.
or
Sterilize the empty and dry infested combs with UV- rays for 20 minutes.
Dust tylocin tartarate or lincomyacin hydrochloride @ 200mg in 20 mg sugar powder
/hive between the combs at weekly interval.
or
Feed oxytetracyclin @ 250-400 mg / 5l sugar syrup (50%)/ colony.
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6. European Foul Brood Disease
European foul brood (EFB) disease was first reported in 1885 from U.K (Cheshire
and Cheyne, 1885) in A. mellifera . In India, it was recorded during 1970 in Maharashtra
(Diwan et al., 1971) from A. cerana and in 1998 from A. mellifera colonies of Himachal
Pradesh and Karnataka. Presently it is prevalent throughout the country in both the hive
bees.
Causal organism : EFB is caused by a non- spore forming, lanceolate, gram
positive bacterium Melissococcus pluton (= Streptococcus pluton). It occurs singly or in
chains or in clusters. The cell size is 0.5-0.9 X 1.0 µm.
Secondary bacteria associated with M. pluton are Bacterium eurydice, Bacillus alvei ,
B. laterosporus and Streptococcus faecalis which do not cause the disease but influence the odour, severity, and consistency of dead brood.
Spread : Infection spreads within the colony from adults to brood and vice-versa by
the bees engaged in cleaning combs and nursing brood activities. Infected queen also
spread the disease through eggs. The disease spreads from colony to colony and other
apiaries through robbing, drifting, absconding, manipulation and migration.
Epidemiology : Larva receives M. pluton with food and the bacterial cells multiply in
the cavity of mid gut at 2-3 days age. Then the cells invade the intestinal epithelium and
compete for food with the host larva. The cells multiply in the larval food and as a result
developing larva demands more food. If the ratio of brood to nurse bees is low, the bees
detect such larvae and eject them out. Under such circumstances, typical disease symptoms are not visible in the colony. The infection with typical symptoms is visible when
there is more number of nurse bees available to over feed the larvae. Thus the death of
the larva is due to starvation.
Field diagnosis
Colour changes from glistening shiny white to pale yellow.
Infected larvae appear somewhat displaced upward or downward direction.
The brood die at 3-5 days age (coiled stage). In A. mellifera , death of the brood
occasionally occurs at pupal stage whereas, in A. cerana it dies generally at pupal
and sometimes in prepupal stages. The disease at this stage, appears similar to
Thai sac brood virus disease and mite infestation.
The rotten larvae emitted sour or vinegar like smell.
On drying, the larvae convert to rubbery scales.
At serious stage of infection, combs show scattered pattern of sealed and unsealed brood.
A. cerana colonies show high tendency to abscond.
Management
Keep colonies in open, clean and dry with shade area.
173
Maintain colony hygiene by cleaning the bottom board frequently.
Keep the bee colonies strong by feeding honey/sugar syrup, uniting weak colonies,
adding healthy young bees and brood combs.
Supply good prolific queens to the colonies.
Isolate the diseased colonies from healthy ones.
Prevent robbing, drifting absconding and avoid migration of diseased bee colonies
to other areas.
Maintain disease resistant stocks through selection and multiplication of honeybee
colonies.
Check the colonies periodically for any abnormalities in brood/behaviour of bees.
Replace the contaminated combs with fresh ones or comb foundation sheets.
Sterilize by treating the contaminated equipment and combs with detergent (surf
excel, 1% solution) containing 1% formalin for 1-2 hrs. Wash with water and dry the
material before use.
or
Treat the dry and empty contaminated equipment and combs with UV- rays for about
15-20 minutes.
Feed the colonies with oxytetracyclin (5% a.i) @ 200mg /300ml sugar syrup (50%
w/v)/colony just at the appearance of disease at least more than one month before
the start honey flow season or during long dearth period.
7. Chalk Brood Disease
It was reported for the first time from A. mellifera in Germany during 1906 and 2001
from Punjab, India (Chhuneja et al., 2002).
Causative organisms : It is caused by a fungus, Ascosphaera apis which infects
larvae only. It is a heterothallic fungus. It develops a characteristics spore cyst when
opposite thallic strains (+ and -) fuse. Spore cyst (enclosing numerous spores) is 17140 m in diameter with 9-19 m thick wall. Individual spore is 3.0-4.0 x 1.4-2.0 m in size.
The spores are very resistant and can remain infective for 15 years and germinate on
finding suitable conditions.
Spread : Its spores spread from honey sac of one adult worker bee of infected
colony to other bee in food exchange. They also spread through contaminated honey,
pollen, drifting of bees, manipulation, queen, and solitary bees by contact in field.
The spread of disease is influenced by chilling of larvae at about 30 O C brood nest
temperature due to over expansion of brood area, poor ventilation, excessive swarming,
summer rains, moist and cool places, weakening of colonies and upset equilibrium of
bee intestinal flora.
Multiplication : Spore infects gut of 3-4 days old larva (anaerobic) of all casts of
174
honey bees which grows into mycelium for a some time. Then in fifth instar stage (aerobic), the mycelium starts developing rapidly in the gut. The infected pupa gets over
grown with white cotton like mycelium which fills entire brood cell. Finally, the white
mass dries into a hard shrunken chalk like mummy. But in the presence of + and mycelia, spore cysts of black - white or completely black colour are also formed.
Field detection
Presence of white fluffy and swollen dead pupae of hexagonal shape of the cells on
the outer part of combs.
Presence of hard, shrunken and chalk like white mummies.
Colour of brood changes from white to grey and finally black or dark blue grey.
Death of brood occurs at prepupal stage.
Under severe incidence, sealed cells of combs contain many lose and hard pupal
remains which produce rattling sound on shaking.
Management
Isolate healthy colonies from diseased ones.
Exercise check on drifting, robbing and swarming.
Prevent chilling of brood and maintain good strength of colonies.
Provide adequate ventilation to the colonies.
Do not keep colonies in shady, cool and dump places.
Selection and multiplication of the disease resistant stock of honey bees.
8. Stone Brood Disease
It is well known in Europe and North America (Bailey, 1981). Its incidence is not
known from India. Both brood and adult bees are susceptible to its attack.
Causative organism : It is usually caused by Aspergillus flaous occasionally A.
fumigatus and sometimes other Aspergillus species. These are common soil inhabitant
but are also pathogens to others.
Mature grown A. flavus is yellowgreen in appearance while A. fumigatus is greygreen.
Both of these are similar under the microscope. Spores affect both unsealed and sealed
brood. Infection occurs either through gut or cuticle of both brood and adults.
Multiplication : After germination of spores on cuticle, mycelia penetrate the subcuticle tissues and produce local aerial hyphae and conidospores. In the gut, spores
after germination into mycelia attack all the softer tissues rapidly. Due to rapid growth of
the fungus, a characteristics whitish yellow collar like ring near the head of the infected
larva is formed. Within 2-3 days, mycelia envelop the whole larvae as false skin. Finally,
spores fill the comb cell containing the infected larvae. After then, the infected bodies
become hardened. The hardened larvae are difficult to crush, hence known as stonebrood. While infected adult bees become flightless and sluggish with dilated abdomen
due to production of toxins from mycelia. The fungus forms spores on dead adult bees.
175
Spread : Through exchange of combs, infected honey and pollen. Poor ventilation
and high humidity enhances the multiplication of the fungus.
Field diagnosis
Presence of white and fluffy brood.
White colour of brood changes to pale brownish or greenish yellow.
Presence of very hard brood
Comb cells containing infected brood are filled with coloured spores
Flightless and sluggish worker bees with dilated and mummified abdomens.
Management
In severe cases, destroy bees, combs and debris.
Use sterilize or fresh equipment.
9. Nosema Disease
It is a disease of adults of both the hive bees. It is recorded for the first time in A.
mellifera in 1909 (Bailey, 1981). It is prevalent throughout the world. All three casts of
honey bees are susceptible to its infection. Infection does not result into death but
causes physiological exhaustation.
Causative organism : It is caused by a spore forming protozoan, Nosema apis . The
spores are microscopic bacilliform with bright and fluorescent edges. These are 4.0 - 6.0
x 2.0 - 4.0 m in size.
Field diagnosis
Infected bees become dysenteric with distended and swollen abdomen.
Wings become disjointed and bees are found crawling in the hive and in front of the
hive.
Droppings of loose yellow coloured excreta are found on the combs or on alighting
board or on other hive parts.
Infected queen stops egg laying due to degeneration of ovaries and colony become
weak as death rate of worker bees exceeds the birth rate.
Nurse bees stop rearing brood as their hypopharyngeal glands deteriorate and shift
to foraging duties.
Lives of worker bees reduce to half.
Spread : Its spores liberated in faecal matter of infected bees which are taken by
house or cell cleaning or polishing bees. Queen and drone bees get infection during their
feeding by infected nurse bees.
Multiplication
Inoculation occurs by ingesting spores.
Spores germinate in mid gut and penetrate epithelial wall.
Multiplication cycle of spore occurs inside the epithelial wall and then are shed into
176
gut. From the gut, some re-infect the same host and remaining come out with faecal
matter. About 30-50 million spores can be found in a worker bee. The spores remain
viable for more than one year in hives.
Management
Overwinter the colonies with good strength and adequate food reserves.
Keep the colonies in open sunny sites.
Provide fresh and clean water in the apiary.
Re-queen the colonies with newly mated queens.
Give temperature treatment to the empty equipment at 49 oC and 50% RH for 24 h for
destroying spore.
or
Sterilize the equipment and empty combs by fumigating with 80% acetic acid @ 150
ml/hive space in stacks for few days. Reuse them after proper aeration.
Feed dependal - M @ 500 mg/l sugar syrup (50%) at an interval of 15 days to each
colony.
Bumble bees are also reported to be infected by virus, bacteria, fungi, protozoa,
enemies and pests. In Himachal Pradesh, 20% of the queens have been found to be
infested with conopid flies (Kiran et al., 2011, Trends in Biosciences 4 (1): 51-52). Some
of the bumble bee colonies have found to be infected with some bacterial disease in the
larval stage.
Warning : Chemical treatments to the colonies should be avoided. If necessary, it
should be given only when there is a long dearth period (>30 days) and honey should not
be extracted from the treated colonies.
Suggested Readings
Abrol, D.P. 1997. Honey Bee Diseases and their Management . Kalyani Publishers,
Ludhiana.
Bailey, L. 1963. Infectious Diseases of the Honey Bee . Land Book, London.
Joshi, N. K. and Verma, S.K. 1985. In : Apis cerana indica Fab. in Kumaon hills of UP,
India. Indian Bee J. 45 : 41-42.
Morse, R. A. 1978. Honey Bee Predators and Diseases . Ithaca, New York, Cornell
University Press.
177
INSECT POLLINATORS ENEMIES AND THEIR MANAGEMENT
S. K. Kakroo
Division of Entomology, SKUAST-Kashmir, Shalimar
Introduction
Jammu & Kashmir has greater amenities for migratory beekeeping between plains
and hills. The state is bountiful in having all the four species of honeybee's viz., Apis
flarae F., A. darsata F., A. mellifera L. and A. cerana indica F. Of them A. cerana indica
F was widely reared species in this region till recently but succumbed to Thai sac brood
virus disease which wiped out more than 99 per cent of the live stock. Consequently,
A. mellifera which is resistant to this virus was introduced successfully in the state.
However, this species is prone to the predatory attacks of members of genus Vespa and
other predator species.
Predators of honeybees in Jammu & Kashmir State
I.
Wasps
2. Wax moths
3. Bee eater birds
4. Ants
5. Toads
6. Lizards
7. Spiders
8. Dragon flies
9. Squirrels
10. King crow
11. Hawk moth
12. Bear
Predatory wasps
Wasps which prey upon honeybees in different areas of J&K State (Kakroo,2004) are :
i)
Vespa orientalis L. (Yellow banded brown wasp)
ii) Vespa velutina (= auraria ) S. (Golden Wasp).
iii) Vespa basalis S. (Black wasp)
iv) Vespa tropica (= cineta ) L. (Yellow banded black wasp)
v)
Vespa mandarinia (= magnifica) S. (Large wasp)
Vespine nest sites
Kakroo, 2004; Matsuura (1971,1984) identified four preferences of nest sites by Vespa
species;
1. above the ground in the open,
2. above the ground in an enclosed space,
3. below the ground in a cavity and
4. some combination of these features.
178
Species'
Vespa orientalis ( Linnaeus )
V. velutina (= auraria ) Smith
V. basalis Smith
V. tropica (= cincta ) Leefmansi
V. mandarinia (= magnifica ) Smith
Habitat
Rock wall/building
Hollows
Bough of tree
Eaves of building
Hill rock wall
Bridge
Bough of tree
Eaves of building
Rock wall
Building crevices / cracks
Other sites
Subterranean nests (Cavities formed by rotten
tree roots or holes made by rodents)
The location and height of nests varies with the Vespine species. V. velutina and
V. basalis make arboreal nests in. open situations on bough of trees, eaves of building
and rock walls. There is no preference for specific trees for nest sites by either species.
V. orientalis make nests in hollows in houses on eaves and on trees.
The nests in hollows are not fully enclosed in papery envelops. V. tropica build its
nests preferably at enclosed situation both above and under ground. V. mandarinia make
its nests at underground locations in subterranean cavities formed either around rotten
tree roots or holes made by small rodents and occasionally in tree hollows close to
surface.
Management of wasps
A. Mechanical flapping
1. Physical killing of wasps by flappers at apiary.
2. Queen killing during spring season
B. Protective screens
Metal screen bee protector consisting of 22.5x8.5x8.5cm. With 7 to 8mm. gap between the wires, should be kept at hive entrance.
C. Destruction of nests
Destruction of colonies within the nest should be done after dark when foraging
activity is ceased.
D. Aerial/Arboreal nests
Aerial nests of the wasps in the vicinity should be located and destroyed by burning
with kerosene torches.
179
E. Subterranean nests
Subterranean colonies can be killed by pouring carbaryl (10% dust) into the entrance hole of nests followed by plugging with cotton or cloth
F. Capsule poisoning
Live Wasps are collected with the help of insect collection net and anaesthized with
chloroform. A capsule containing insecticide is tied to the anesthized Wasp's hind leg
and then released. The Wasp along with the poisonous capsule enters into the Wasp
nest. Gradually other wasps along with the poison capsule enters the nest which results
accumulation of poison and colony wasps get killed.
G. Trapping of Vespine wasps
i)
Fish/wetting agent/water trap.
ii) Sugar syrup/fermented honey traps.
iii) Bait traps - Water : talcum powder : chopped meat + 0.1% malathion (50 EC)
i)
Fish/wetting agent/water trap
A raw fish suspended several cm. above pan filled with water to which a wetting
agent is added can be used for capturing I killing Wasps. The skin of the fish on the
sides should be cut to give ready access to the flesh taken by Wasps. Typical workers
behaviour is to cut a piece of flesh from the carcass, then to fly a short distance where
it alights to trim the flesh piece to a manageable size. The initial piece is frequently too
heavy to be carried by the workers and most of them fall, sink and drawn into the water
whose surface film has been reduced by the wetting agent. This method was described
by Akare et al. , (1980).
ii) Sugar syrup/fermented honey traps
The method as described by Thakur et al., (1996) can be used for trapping / killing of
Wasps. A trap consists of a wooden chamber (30 x 30 x 30 cm) fitted with 16 mesh wire
gauze screens on the top and back side. On one side a door is kept to facilitate keeping
poison bait inside the chamber and to remove the dead Wasps from it. A plastic jar (13
cm high and 10.5 cm dia.) fitted half inside the wooden chamber. A round hole of 4 cm
dia. made in the lid of the jar. A 16 mesh wire gauze tunnel of 15 cm length is fitted to the
hole in the lid. The tunnel is 4 cm. in dia. at the base and 1.5 cm on the other end. A
triangular hole (3 x 3 x 3 cm.) on the other side 1cm. above the bottom of the jar is
made. Lure solutions are kept in the plastic jar and poisonous bait (sugar or fermented
honey)+ 0.1% malathion (50 EC) in the ratio 2:1 is placed in the wooden chamber to kill
trapped Wasps. Traps may be placed in the apiary 1.5 mt. behind the beehives. During
this period all the hive should be protected with a bee protector consisting of µ 5 x 8.5 x
8.5 cm. metal screen with 7-8 mm gap between the wires at the hive entrance to enable
free movement of bees and to discourage the predatory activity of Wasps.
iii) Bait traps
Water : talcum powder: chopped meat + 0.1% malathion (50 EC). Wasps prefer
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dead decaying putrefying material with alcoholic contents whereas bee do not. This
behaviour of Wasps can be utilized for their control.
Wax moths : Wax moth species
Two species of wax moth are found causing considerable damage to honey bee
colonies and frames in storage.
a) Greater wax moth ( Galleria mellonella L.)
b) Lesser wax moth ( Achroia grisella F).
Management :
i)
Regular inspection of bee hives.
ii) Though any colony is prone to the attack of wax moth, strong colonies are able to
resist it.
iii) Keep the hives without cracks and crevices.
iv) Hive entrance should be reduced which can be effectively guarded by bees.
v)
Removal of all combs which are not covered with bees, especially during dearth
periods.
vi) During the normal examination of colonies, the debris on the bottom board should be
scrapped and cleaned with hive test.
vii) Tunnels of larvae in combs can be seen if it is held against the Sun rays. The larvae
can be killed in the initial stages and silken webs are cleaned.
Non chemical control
All stages of wax moth are killed in combs at 46°C for 70 minutes or at O°C for 270
minutes.
Chemical control
Sulphur dusting on the top bars of comb frames in hive body is suggested
Sulphur smoldering at 180 g per one cubic meter of space on a stack of 4-5 hive
bodies in air tight condition in store. Fumigants such as acetic acid calcium cyanide,
ethylene dibromide, pardichlorobenzene and phosphine have been used in different countries to protect honeybee products, especially combs from moths during storage (Cantwell
1970, Burges 1981, Shimanuki 1981).
Bee eater birds
a) Merops orientalis (Latham) and
b) M. supercilasus L. do much harm in apiaries.
c) King crows Discrurus macrocercus (V) and D. ater (N) occasionally visit apiaries on
cloudy days and prey upon bees. Birds sit on trees or telegraph/electricity wires
near apiary and pick the bees on wings.
181
Management
Scaring them away from apiaries is suggested.
Ants
Various species of black ants. viz., Camponotus compressus (Fab), Monomorium
indicum (Morell) and M. destructor (Ters) intrude bee hives and take away honey, pollen,
brood and other debris. Ant attack is more serious in weak colonies.
Management
1. Place the hives on stand with their legs in earthen pot containing water.
2. Removing rotten wood and other plant material extra from the apiary site.
3. Insecticide application into the nests of the ants.
Bear
Bear is also one of the destructive predators of honey bee colonies in J&k. It causes
considerable damage where colonies are located at higher altitudes.
Management
I.
Development of inexpensive bear proof fence.
II. Use of electric fences to protect bee colonies from bears.
III. Scaring of bears by fire, gunshoots flashlights and noise.
Suggested Readings
Abrol, D. P. 1994. Colony behaviour and management of social wasp Vespa velutina
Smith (Hymenoptera: Vespidae). Attacking honey bees colonies. Korean Journal
of Apiculture 9 : 5-10.
Akre, R. D.; Dreene, A.; MacDonald, IF.; Landolt, P. I. and Davis, H. G. 1980. The yellow
jackets of America North of Mexico. United States Department of Agriculture,
Agric. Hanbook 552 pp.
Bhalla, P. P. and Daliwal, H. S. 1980. Potentialities and progress of the beekeeping in
India. Proc. 2nd Int. Conf. Apic-Trop. Climates New Delhi. Feb. 29-March 1980 :
110-112.
Burges, H. D. 1981. Control of wax moths: physical, chemical and biological methods.
Bee World 59 : 129-139.
Cantwell, G. E., and L. Smith. 1970. Control of the greater wax moth Galleria mellonella,
in honey comb and comb honey. American Bee Journal 110 : 141.
Jyothi, V. A. 1989. Ecological and physiological studies on greater wax moth Galleria
mellonella L. Ph. D. Thesis, Bangalore University, India.
182
Kakroo, S.K. 1993. Studies on seasonal incidence of honey bee diseases and natural
enemies . M.Sc. Thesis, Sher-e-Kashmir University of Agricultural Sciences &
Technology, J&K.
Kakroo, S. K. 2004. Studies on Vespine wasps predating honey bees ( Apis mellifera L.).
Ph. D. Thesis, Sher-e-Kashmir University of Agricultural Sciences & Technology,
Jammu.
Kudrayavastava, O. K. 1977. Breeding for nectar productivity in order to increase seed
yield and improve the food base of bees in pollination of agricultural crops by
bees. American publishing Co. Pvt. Ltd., New Delhi 145 pp.
Matsuura, M. 1971. Nesting sites of the Japanese Vespa species Vespidae).
(Hymenoptera Vespidae). Kontyu 39 : 43-54.
Matsuura, M. 1984. Comparative biology of the five Japanese species of the genus Vespa
(Hymenoptera: Vespidae). Bull. Fac. Agric. Mie. Vniv . 69 : 1-131.
Okada, I. 1989. Three species of wax moths in Japan. Honeybee Science 9 : 145-149.
Ono, M; Igarash, T; Ohno, E. and Sasaki, M. 1995. Unusual thermal defence by a honey
bee against mass attack by hornets. Nature London 377 : 334-335.
Sakagami, S. F.; Matsuura, M. 1972. Aspect of the biology of Vespa mandarinia,
A serious. enemy of apiculture in Japan. Homenagem -a- warwick -E-Kerroferecidapelos-seus-exalunos-por-ocasias-de-seu- 50-deg-aniversaria
251-258 pp.
Shah, F. A. and Shah, T. A. 1991. Vespa velutina, a serious pest of honey bees in
Kashmir. Bee World 72 : 161-164.
Shimanuki, H. 1981. Controlling the greater wax moth - A pest of honey combs. U.S.
Department of Agriculture Farmers Bulletin number 2217.
Sihag, R. C. 1982. Problem of wax moth ( Galleria mellonella L.) Infestation on Giant
honeybee ( Apis dorsata Fab.) colonies in Haryana. Indian Bee Journal 44 (4) :
107-109.
Singh, S. 1962. Beekeeping in India . Indian Council of Agricultural Research, New Delhi,
India.
Thakur, S. S. and Kashyap, N.P. 1996 Wasp control by lure trap in apiary. Insect
Environment 2 : 6-7.
Zhou, Y. F. Luo, Y. X, Chen, H. S. and Lai, Y. S. 1989. Occurrence and harmfulness of
Galleria mellonella L. (Lepidoptera pyrali.dae ). Natural Enemies of Insects 11 (2)
: 87-93.
183
POLLINATION ENERGETICS
D. P. Abrol
Division of Entomology,
Sher-e-Kashmir University of Agricultural Sciences & Technology, Jammu
The pollinators are highly selective in their floral visits and are shown to choose
those flowers which best meet their energetic needs. The energy needs and foraging
dynamics of pollinators are dependent upon prevailing weather conditions which
regulate the schedule of activities thus influencing the energy budget. The pollinators
are highly sensitive to variations in nectar rewards and alter their foraging behaviour
patterns with change in floral rewards.
Heinrich and Raven's (1972) feature article in 'science' emphasized the role
of energetics pollinator-plant interaction. their ideas dealt with the study of energetic
strategy a plant should evolve to secure the services of a particular pollinator. in pollinator-plant interaction. the publication of this article stimulated researchers all over the
world to discover and test hypotheses governing.
The flower must provide sufficient energetic reward to be attractive to the potential
pollinator to restrict the latter to a single plant species. In most plants, pollinators' visits
(and hence outcrossing) results only if the food rewards of the flowers are in balance
with the energy needs of the pollinators.
The flowers of a plant species must provide sufficient food to be competitive with
other concurrently blooming flowers that the pollinators could potentially visit. Mismatches
in energy needs of pollinators and energy availability in flowers may result in inadequate
pollination. Since 1972, several studies pertinent to their ideas have emerged. This
paper addresses to the question how the energy requirement of pollinators and energy
availability in flowers may result in inadequate pollination and influence their foraging
strategies.
Energy requirement-reward system and pollinator-plant interaction
Plant pollinator interaction, besides biological and physical features such as colour,
shape and odour of the flowers, is governed by the energy needs and pay-offs as its
basic components. The pollinators differ in their energy requirements from low (such as
in ants and flies) to high (e.g. in endothermic groups like mammals and birds)(Heinrich,
1975a, b, c, 1977, 1979, 1981, 1983; Hickman, 1974; Abrol, 1992a, 1993a, 1997, 2000).
Rewarding system developed by the flowers enable pollinators to discriminate between
the closely related plant species or ecotypes. This has resulted in a co-partnership
between the flowers and their pollen vectors. Co-Evolution has brought a close correlation between pollinator needs and floral energy expenditures (Heinrich, 1975a, b). Though
pollen is an important food reward but its importance in pollination energetics is less
than nectar due to its being a protein source, in bees mainly used for egg maturation
and larval development? Pollen is relatively more important food for solitary bees than
184
the social bees. The latter need continuous influx of energy for heating the nest which
accelerates the brood development. The major sources of energy are the nectar sugars
which make a basis of the pollinator-plant interaction. The plant species which are
pollinated regularly by animals with high energy requirements must provide large amounts
of nectar if cross-pollination is to be accomplished.
The intake of energy and profitability depend upon the quality and quantity of floral
rewards (Heinrich, 1975a,b, 1976,1979,1983; Sihag and Kapil, 1983; Helverson and Reyer,
1984; Abrol, 1986a; Alm et al. ,1990; Abrol and Kapil, 1991; Comba-Livio, et al. , 1999;
Nicolson 2007; Fleming et al. , 2004, 2008; Barrera and Nobel 2004; Johnson and
Nicolson 2008; Mitchell et al. , (2009): Brandenburg et al ., 2009). These functions in
turn are under the key control of physical environment which interact in complex ways
influencing not only the physiology of the plants but also that of pollinators in a manner
that functional activities of both of them synchronize (Corbet, 1978a, b, c, 1990a). The
various parameters determining energy intake and expenditure are detailed below:
Energy intake
Nectar is a complex mixture of substances belonging to diverse biochemical classes
and its chemical composition is highly variable (Brandenburg et al. , 2009). Both quality
and quantity of nectar are important in determining the pollinator-plant interaction. Since
the characterization of nectar as an attractant, many workers have recognised the
importance of quality and quantity of nectar that influence abundance of floral visitors
(Butler, 1945; Mommers, 1977; Corbet, 1978a, b, c; Corbet, et al. , 1993; Kapil and Brar,
1971; Southwick et al. , 1981; Sihag and Kapil, 1983; Southwick, 1986; Abrol and Kapil,
1991; Abrol, 1990a, b, 1992, a, b,1995; Abrol 2010, 2011). Whereas some workers
stressed more on the predominance of quality of nectar in attracting bees (Sihag and
Kapil, 1983; Alm et al. , 1990; Abrol and Kapil, 1991), others have failed to establish
such relationship. It has been emphasized in general that high nectar sugar concentration is desirable for attracting the honeybees (Moffett et al. , 1976). The feeding studies
have shown that intake of sugar syrup in bees is a function of threshold of acceptance of
total sugars, that ranged between 5 to 40 per cent (Frisch, 1950), while a few others
specified that the acceptance range lies in between 30-50 per cent (Jamieson and Austin, 1956; Waller, 1972), and bees rejected solution with sugar concentration less than
20 per cent. It has also been reported that honeybees can discriminate a sugar solution
with a difference of 5 per cent concentration (Jamieson and Austin, 1956).
A wide variety of floral types acceptable to honeybees exist in various parts of the
world and many among them are rich sources of honey due to the production of good
quality of nectar. Large variations have been reported to occur in both the quality and
quantity of nectar in different flower sources at inter- and intra-specific levels (Simidchiev,
1977; Real, 1981, 1983; Sihag and Kapil, 1983; Crane et al. , 1985). Various workers in
a variety of plant species recorded sugar concentration ranging between 4-87 per cent
(Shaw, 1953; Deodikar et al. , 1957; Sharma, 1958). Percival (1965) reported nectar sugar
concentration variations from 5 to 74 per cent in plants from Britain. Rowley (1976)
observed 2-95 per cent from Philippines, Sihag and Kapil (1983) reported 24-62 per cent
185
from Hisar (India). Considerable variations have been reported in sugar concentrations of
even the same crop. For example, the nectar sugar concentrations of alfalfa have been
reported to vary between 38-55 per cent (Cirnu et al. , 1975); 20-81 per cent (Pederson
and Bohart, 1953) and 63-68 per cent (Loper and Waller, 1970). In Brassica crops also,
variable amounts of nectar-sugar concentrations have been reported. In general, nectar
sugar concentration has been reported in the range of 33-71 per cent at different geographical locations by various workers (Kapil and Brar, 1971; Sihag and Kapil, 1983).
The difference in nectar sugar concentration may be due to varietal differences and/or
due to geographical locations (Teuber and Barnes, 1978). Pernal and Currie (1998) found
that in case of oilseed rape significant differences in nectar sugar content were also
found in relation to the bloom phenology of the cultivars. Cultivars produced the greatest
amount of sugar per flower during the first two weeks of the bloom period, and then sugar
production decreased in the third and fourth weeks.
Energy reward and the competition for food
Silva and Dean (2000) found that in onion flowers the average amount of nectar
produced by both the umbels and the individual florets was significantly positively
correlated with the number of bee visits. Evidently, selection of flowers with high nectar
production may lead to a higher rate of pollination of the onion seed crop. Ish-Am and
Eisikowitch (1998) reported that at the beginning of the blooming season, the avocado
flowers competed for nectar-foraging bees mainly with flowers of Citrus spp., and for
pollen foragers with Brassicaceae and Fabaceae, all of which were more attractive to
the bees. However, toward the end of its blooming season, the avocado competed with
Poaceae, Asteraceae and Apiaceae flowers, and its relative attractiveness increased.
Wilms and Wiechers (1997) reported that niche overlap between Melipona bees and A.
mellifera was more evident for nectar than for pollen. Goulson, et al., (1998) found that
both honey bees and bumblebees, Bombus spp., can mark rewarding flowers with scent
marks that promote probing by conspecifics. Goulson-Dave, et al ., (2001) obtained
evidence for direct detection of reward levels in two bee species: Agapostemon nasutus
was able to detect directly pollen availability in flowers with exposed anthers, while Apis
mellifera appeared to be able to detect nectar levels of tubular flowers. A third species,
Trigona fulviventris , avoided flowers that had recently been visited by conspecifics,
regardless of reward levels, probably by using scent marks. This can be interpreted as
indirect evidence of actual competition for food. Page et al. , (1998) tested honeybee
foragers for their proboscis extension response (PER) to water and varying solutions of
sucrose. They found that responses were related to nectar and water reward perception
of foragers.
Nectar sugar concentration fluctuations
Sugar concentration in nectar changes from hour to hour and day to day. These
changes, in turn, are reflected in the spectrum of flower visitors (Heinrich and Raven,
1972; Corbet, 1978a, b, c; Corbet et al. 1979; Corbet, et al. ,1993; Teuber and Barnes,
1979). Changes in nectar sugars reflect a situation that is complicated by the interaction of a number of factors that influence the amount and concentration of nectar present
186
in a flower at a time. These may be due to the activity of nectaries (secretion or
re-absorption), equilibration with humidity of the air (evaporation and condensation) and
removal of nectar by flower visitors.
Insect activities influence the total yield of nectar in flowers. Boetius (1948) and Raw
(1953) found that flowers from which nectar is periodically removed yield, in total, more
nectar (containing more sugar) than do flowers which have not been disturbed over the
same period. In almonds, following intermittent rains, honeybees rejected nectar of about
9-15 per cent concentration and collected pollen exclusively till the nectar concentration
rose to 25 per cent (Abrol, 1993a). Energetically, the dilute nectars provide very low
calories and bees are exposed to the extra load of water to be removed through evaporation. Kleiber (1935) found that honeybees stopped visiting lime flowers when the nectar
dried up in the afternoon but resumed their visits when nectar became more dilute in the
evening. This clearly indicates the importance of relative humidity on nectar concentration and insect visits. On a humid day the pattern of change in nectar would be quite
different, and because of the effects of weather and nectar concentration on insect
visits, the pattern of change in nectar volume and sugar contents would be quite different
too. Weather, therefore, also affects post secretory changes in the nectar as well as
insect visits.
Feeding niches of pollinators in relation to their preferred nectar concentration ranges
The concentration of sugar in nectar influences the visits of nectarivorous animals to
flowers. There are some evidences that different groups of flower visitors differ in their
choices of nectar concentration groups ranges (Percival, 1965 Table 1). The lower value
in each case represents the dilute nectars. If the more concentrated nectars are
included in the table then the sequence will end with short tongued flies, because tVhe
viscous solutions cannot be sucked by insects with long tongues. Betts (1930) has
shown that sucking rate of honeybees declines markedly when the concentration of
sugar syrup on which they feed exceeds 50-60 per cent.
Table 1.
Preferred nectar-sugar concentration ranges of different flower visitors (Percival, 1965)
Visitor type
Preferred sugar concentration ranges (%) in nectar
Moth
8-18
Bat
14-16
Bird
13-40
Butterfly
21-48
Honeybee+bumble bees
10-74
Short tongued flies
(Higher)
Long tongued flies
(Still higher)
Simpson (1964) showed that honeybees taking up such concentrated solutions
diluted them to very few percent by spitting into them only watery saliva from their labial
glands. Lepidopterans can make concentrated solutions more easily potable by spitting
187
labial gland secretion into the drink. Both lepidopterans and bees seem to feed on only
moderately concentrated nectars in the field. Short tongued flies on the other hand take
nectar at high concentrations (Elton, 1966) and readily feed on crystalline sugar. They
do this by spitting on their food and lapping up the solution. This spit and lap mechanism enables flies to exploit dry nectar abandoned by bees in the heat of the day (HansenBay, 1976).
Nectar secretion pattern and its influence on pollinator-plant interaction
Time sense in honeybees as well as rhythmicity in nectar secretion in flower types
has been of great significance in the pollination of various entomophilous plants. The
bees have been found to anticipate seasonal and diurnal changes in the caloric reward
of their host plants (Frankie et al. ,1976) and adjust their collection activities to the
rhythms of nectar production (Corbet, 1978a, b, c; Sihag and Abrol, 1986). When a plant
has two peaks, the bee activity may coincide accordingly. Bimodal pattern of nectar
secretion has been observed in most of the plants (Corbet et al. , 1979; Real, 1981;
Lack, 1982; Pelmenev et al. , 1984; Abrol 1986b. 1987). However, more than two peaks
may occur in some plants depending upon genus or sub-family (Pesti, 1976). Nunez
(1977) found that flight activity of honeybees collecting nectar coincides with the nectar
secretion pattern of host plants. The coincidence pattern of nectar secretion and pollinator visitation has an Evolutionary significance. Plants produce nectar when their potential pollen vectors are available. The pollinators also avoid visiting flowers at times when
rewards are not available. This strategy on the parts of the plants and pollinators has
brought a coEvolution of the diagonally apart, yet mutually linked organisms.
Nectar composition and caloric content-their influence on pollinator-plant interaction
Considering the diversity of pollinators and their different energy needs, nectars are
highly variable in sugar composition, concentration and caloric content. The caloric rewards available in flowers of different plant species in Central America varies from less
than 0.03 mg to approximately 1800 mg- a difference of 60,000 times (Hainsworth and
Wolf, 1972a, b; Heithaus et al.,1974; Stiles, 1975). The amount of sugar in "bee flowers"
may be < 1 mg per floret whereas in "bird flowers" and "bat flowers" it is appreciably
higher (Shaw, 1953; Percival, 1965; Hainsworth, 1973; Heinrich, 1975b; Stiles, 1975;
Baker, 1979). Bat flowers contain some of the largest amount of sugar. Up to 15 ml of
nectar is produced per flower per night by some bat pollinated flowers in West Africa
(Baker and Haris, 1957) and Costa Rica (Heithaus et al. , 1974). Whether a given caloric
reward is presented as dilute or concentrated solution is important in the energetics of
foraging. It is assumed that 1 mg of sugar, regardless of type; yield about 4.0 cal,
probably a reasonable estimate for most ecological questions.
The most common sugars in the nectar are a disaccharide: sucrose, and two monosaccharides: glucose and fructose. Sucrose predominates in most of the flowers with tubular corolla and its hydrates, glucose and fructose, in open flowers (Wyke, 1953; Bailey
et al. , 1954; Percival, 1961; Stiles, 1975; Corbet, 1978b).
188
Majority of the plant species investigated by Rowley (1976) in Philippines had the
dominance of sucrose. Sihag and Kapil (1983) studied nectar sugars of 44 plant species
in subtropical Hisar (India) and found that sucrose dominated in 13, glucose in 24 and
the rest contained equi-proportioned glucose (G), fructose (F) and sucrose (S). Bahadur
et al. , (1986) found that SGF type of sugar composition was the most common occurring
in 56 out of 100 species investigated. In a later study, Baker and Baker (1983) found that
out of 765 plant species examined, sucrose, glucose and fructose combination was
most common (649 plants) followed by glucose and fructose (78 plants); Sucrose and
fructose (29 plants); sucrose alone (7 plants) and glucose alone (2 plants); whereas
sucrose+fructose or only fructose was not detected in any of the plant species. Abrol
and Kapil (1991) found sucrose, glucose and fructose as the main components of nectar
in most of the agricultural crop plants. Parkinsonia aculeata L. and Pongamia glabra L.
contained traces of maltose also. Abrol and Kapil (1991) further found that total
caloric reward matters more to the pollinators than the proportion of consequent sugars.
Generally, pollinators with high energy requirements foraged on sucrose rich flowers,
whereas, those with low energy requirements relied on glucose or fructose rich flowers.
They also explained the relative attractiveness of different sugar components to different
pollinators in relation to energy needs and the possible origin of maltose.
Different nectar feeders have been reported to vary in their preferences (Baker
and Baker, 1979, 1982). Small bees preferred broad spectrum nectar; big bees,
lepidopterans and humming birds preferred sucrose rich; and flies, passerine birds and
bats preferred sucrose poor nectars. This partitioning of resources reduces competition
and ensures the co-existence of several nectar feeding animals in a community.
Nectar sugars vary in their taste to bees, and consequently in their attractiveness
too. Frisch (1950) categorised the nectar sugars into following different classes :
(i) nectar sugars sweet to bees: sucrose, maltose, glucose, fructose, trehalose and
melizitose;
(ii) nectar sugars tasteless to bees: lactose, melibiose, raffinose, xylose and
arabinose;
(iii) nectar sugars toxic to bees: mannose and galactose; and
(iv) nectar sugars repellent to bees: cellobiose and gentibiose.
Wyke (1952a, b) concluded that honeybee prefers a "balanced nectar" with roughly
equal amounts of glucose, fructose and sucrose. Percival (1961) in his extensive nectar
survey studies revealed that balanced nectars are very uncommon in plants. Waller
(1972) disputed Wyke's claim and showed that honeybees preferred sucrose rich
liquids. Sihag and Kapil (1983) and Abrol and Kapil (1991) also supported the Waller's
contention but stated that the bees preferred nectar with one dominant sugar and not
the equi-proportioned sugars as has earlier been reported by Wyke (1952a, b).
However, birds have been reported to show a different pattern of nectar preferences.
Hainsworth and Wolf (1976) found that birds preferred nectar sugars in the order: SFG =
SF>S>FG>SG>F>G. However, Stiles (1975) found a different order of nectar preference
189
which was S>G>F (where S=sucrose, F=fructose and G=glucose). Nearly all birds rejected fructose in any comparison test. Van Riper (1960) also found that broad tailed
hummingbird (Selasphorus platycerus) preferred sucrose and glucose. Josens, et al.,
(1998) found that in case of nectar feeding ant, Camponotus mus both sucrose concentration and viscosity of the ingested solution modulate feeding mechanics as well as
workers decision about the load size to be collected before leaving the source. In a
similar study, Josens and Roces (2000) found that responsiveness of foragers of nectar
feeding ant, Camponotus mus, determined by the nutritional state of the colony,
influenced both foraging decisions and the dynamics of fluid intake.
The presence of certain amino acids in nectars have been considered of Evolutionary
significance. Baker and Baker (1973a, b, 1975, 1977) and Baker et al. , (1978)
concluded that occurrence of amino acids in floral nectars is a universal phenomenon
and reported amino acids in the nectars of 260 out of 266 plants studied. They also
pointed out that amino acids in nectar may be important in the nutrition of nectar feeding
insects, as well as contributing to taste and feeding stimulus, although their amounts
are small in comparison to the concentration of sugars.
Measurement of energy costs
The energy costs of foraging pollinators must be less than the energy gains. The
profits must be sufficient for long term energy balance. Different methods for measurement of foraging energetics vary depending upon the conditions as follows:
1. Direct measurement of food consumption, particularly when foods are chemically
defined as sugars from nectar, can be reliable indicators of energy expenditure
especially in honeybees and humming birds that presumably not accumulate far
reserves. Rapid utilization of sugars by these animals has made it possible to compute 24/hr energy budgets on the basis of food intake.
2. The standard and most reliable indicator of energy expenditure is the rate of either
oxygen consumption or carbon dioxide emission. Animals feeding on nectar sugars
generally have respiratory quotient close to 1.0 and every milliliter oxygen consumed
or carbon dioxide liberated is equivalent to an energy expenditure of 5.0 calories or
83.70 joules. By far the greatest bulk of food stuffs in nectar is sugar, which yields
about 4 calories per milligram. Hymenoptera and Diptera have respiratory quotient
(RQ) equal to 1.0 indicating that their flight muscles use primarily carbohydrates.
The method has some limitations that the natural conditions are difficult to be
obtained in animals confined to respirometers. However, when combined with careful
field observations the measurements can be a powerful tool to infer energy budgets.
Morrant et al. , (2009) developed the Methods for sampling and storing nectar from
the flowers of species with low floral nectar volumes (<1 µL) using the flowers of
Eucalyptus species. They recommended the washing for nectar collection from
flowers with low nectar volumes in the field (with the understanding that one wash
underestimates the amounts of sugars present in a flower), as is immediate analysis
of sugar mass.
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3. Energy budgets can also be determined by the use of isotope- labelled water. Monitoring the amount of isotope in the blood after a given amount has been injected
provides an indication of the amount of energy expended during the time between
injection and sampling. The isotope labeling method is ideal for social insects
because these animals can be recaptured in the field after a given interval (Mullen,
1971; Utter, 1973).
4. Body temperature is possibly the most reliable indicator of "instantaneous" energy
expenditure of free living animals in which discrete activity states are not apparent
through visual inspection. At least 80% of an animal's energy expenditure is
degraded to heat, due to inefficiency at biochemical and mechanical levels of
organisation (WeisFogh, 1972). An increase in heat production is usually accompanied by an increase in body temperature (Heinrich, 1974a, b, and 1975c, d). The
method has been useful for determining the energy expenditure of flying birds and
insects (bumblebees) (Weis-Fogh, 1972; Heinrich, 1972).
Energy expenditure
Energy expenditure of some insects while thermoregulating depends upon the body
size. On the basis of whole body weight, the metabolic rate of a bumblebee while incubating is 170 cal (g hr)-1 at 0 oC. A hummingbird weighing 10 times more than the bee
has a weight specific respiratory rate 2-4 times less than that of the bee, and a bat
weighing 10 times more than the bird has a respiratory rate at the same temperature 2.8
times less than that of the bird (Heinrich, 1975d). The smaller the animal, the greater is
the energetic barrier to activity at low ambient temperature. Bartholomew (1968) pointed
out that as long as small animals maintain high body temperature, they are never more
than a few hours from death by starvation, particularly at low ambient temperatures.
Hill-Peggy et al., (2001) observed that foraging decisions are based on a suite of choices
that include energetics physiological constraints. Although traveling farther to harvest a
greater net energetic reward is beneficial, many animals opt for a smaller net reward
that requires less travel.
The state of activity of rest and ambient temperature have great influence on energy
expenditure. For example, a hummingbird weighing 8 g may increase its metabolic rate
from about 9.0 cal (g hr) -1 to 65 cal (g hr) -1 at 0oC (Hainsworth and Wolf, 1972b). A
stationary bumblebee weighing approximately 0.5 g increases the metabolic rate of its
thoracic muscles from 85 cal (g hr)-1 to 850 cal (g hr) -1 over the same range of ambient
temperatures while incubating brood (Heinrich, 1974a).
Many pollinators have evolved mechanisms to overcome periods of severe energy
problems. Since many flowers bloom only for short durations, the high energy demanding pollinators face acute problems. Some insects during this period undergo torpidity.
Social insects such as bumblebees avoid this torpidity by storing food energy in the
nest. A queen bumblebee may use the entire contents of her honey pot in a single night
(Heinrich, 1974a, 1975d). When all the available food has been utilized, the bee enters
torpor (Heinrich, 1972). When at 0 oC, a torpid bumblebee has a metabolic rate 10002000 times less than when it is regulating its body temperature (Heinrich, 1974a, b;
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Kammer and Heinrich, 1978). Thus, these energy saving mechanisms help the pollinators to overcome unfavourable or dearth conditions.
The rates of increase in the body temperature are strongly size dependent (Pereboom
and Biesmeijer, 2003). For example, a bumblebee weighing 0.6 g may warm at 12 oC in
one min (Heinrich, 1975d) but an animal weighing 300 g warms up about 120 times less
rapidly (Pearson, 1960; Barthalomew et al. ,1970). The energy costs for warm up are
nearly unfavourable for large animals. For example, a bumblebee weighing 0.5 g costs
7.5 cal to warm up from 13.5 oC to 38.0oC (Heinrich, 1974b) which is equivalent to the
energy expenditure during 3.0 min of flight. A sphinx moth weighing 2.0 g requires 30 cal
to warm up from 15 oC which is equivalent to the energy expended during approximately
3.7 min of flight (Heinrich, 1971a,b; Heinrich and Casey, 1973). A small bat or hummingbird expends 114 cal during a warm up from 10oC, corresponding to approximately 1.2%
of the total energy budget for 24 hrs. In contrast, a 200 kg bear would need as much
energy to warm up as it uses during an entire 24 hr activity period (Pearson, 1960).
The highest energy costs, other than thermoregulation, are those of locomotion.
Flight, particularly hovering (Tucker, 1968; Weis-Fogh, 1972), is a metabolically the
most expensive mode of locomotion, although for a given distance of travel it can be
energetically less costly than waling (Tucker, 1968; Weis-Fogh, 1972; Hainsworth and
Wolf, 1972b; Epting and Casey, 1973). For insects and birds, the energetic cost of flight
has been shown to vary markedly with load (Berger and Hart, 1974; independent of
ambient temperature (Betts, 1930; Hart and Berger, 1972; Heinrich and Casey, 1973;
Heinrich, 1975d).
Cost-benefit analysis and pollinator behaviour
Energy requirements of pollinators govern their foraging relationship with flowers.
The interdependence of pollinators and flowers depends upon the balance sheet they
share with each other. Each pollinator moulds its efforts in such a way that it can maximize the reward. Energy intake and expenditure depend upon the allocation of time into
various daily activities e.g. rest, flight and hovering etc. Time energy budgets have extensively been studied in birds especially nectarivores (Gill and Wolf, 1975a, b; Wolf
and Hainsworth, 1971; Wolf et al. , 1972, 1975; Wolf, 1975), solitary bees (Abrol, 1986a,
1989,1993b), honeybees and solitary bees (Abrol, 1992a) and dragon flies (Fried and
May, 1983). Abrol (1986a, 1989,1992a, 1993b) studied the time budgets of honeybees
and solitary bees and categorized their daily activities into foraging, active and resting
periods etc. Wolf (1975) studied the time budgets of Nectarina famosa males and
allocated their activities into sitting, fly catching and chasing. Likewise time energy
budgets of Apis florea, A. dorsata Megachile cephalotes, M. lanata, Xylocopa fenestrata,
Pithitis smaragdula (Abrol, 1992a), Andrena ilerda, A. leaena (Abrol, 1989) and Megachile
femorata (Abrol, 1993b) have been worked out.
Co-evolution has brought a close correlation between pollinator needs and
expenditures of food energy. Each pollinator modifies its behaviour in such a way that
maximizes its net energy gains. Thus the foraging strategies vary accordingly (Faegri,
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1978; Abrol, 1986a, 1989, 1992a, 1993b; Moffatt-Luciano, 2001; Cakmak-Ibrahim and
Wells-Harrington 2001). Environmental factors such as atmospheric temperature, relative humidity, light intensity, solar radiation and time of the day influence the energy
relationship of pollinators with flowers (Riessberger and Crailsheim 1997; Abrol 1998a.
Energy budget balance indicated that bees with higher energy requirements do not
forage on the flowers providing low caloric rewards (Abrol, 1992a., Klinkhamer and
Jong.1993; Marden and Waddington, 1981). The carpenter bee, X.fenestrata with higher
energetic requirement rarely visited Medicago sativa, Trifolium alaxandrinum, Coriandrum
sativum , Foeniculum vulgare, Daucus carota, Allium cepa and Brassica group of crops
which provide low caloric reward inadequate to meet its higher energy demands. Another
factor limiting the visit of X. fenestrata to these crops is the poor correlation between
the morphology of the flowers and the bee which makes its landing on these flowers
difficult. In general, size of the flower and caloric reward in relation to the size of the
visitor and energy demands seem to be the determinants for resource partitioning among
various species of bees and permitting thus co-existence under similar ecological
conditions (Abrol, 1992a). The population of certain species of pollinators visiting
certain flowers was found to be a function of their own size as well as the size of the
flowers, since the feeding pattern of many animals differ as a function of trophic apparatus (Harder, 1985). X. fenestrata visited Cajanus. cajan, Parkinsonia aculeata, Pongamia
glabra and Luffa cylindrica flowers (Abrol, 1992a). The flowers of these crops are relatively large, suitable for landing and provide sufficient caloric reward. The bee can handle
these flowers efficiently and maximize obtainable gain as net energy. Similarly, flowers
of F. vulgare, C. sativum, D. carota, A. cepa. Trigonella foenumgraecum var Kasuri and
Mangifera indica were not attractive to A.dorsata because the bee could make no profit
from these crops. However, A. dorsata collected pollen from these flowers by treating
the inflorescences as a single unit and walked over the massed florets. Though Brassica
crop were intermediate to umbelliferous and leguminous crops in energetic rewards, A.
dorsata visited in the early hours of the day when the flowers had peak periods of nectar
production, and then the foraging populations shifted to other high rewarding crops.
However, A. florea with small energetic needs commenced activity between 1000 h and
1100 h and dominated on the later crops throughout the day. The latter bee species with
its smaller size and body weight is physiologically and morphologically better adapted
to extract maximum reward from these flowers. Because of relatively low energy requirements, the bee is still able to maintain an energy balance and visited these crops in
large numbers. Sihag and Kapil (1983) reported that A. florea visited Brassica crops in
larger numbers than A. dorsata . They attributed this to a differential response of bees to
their energy demands. In Brassica crops, exceptions were B. juncea and B. carinata
where foraging populations of A.dorsata were also large. Interesting situation was
observed in case of M.sativa and T. alexandrinum which bloom simultaneously and
compete for pollinators. M. sativa has comparatively higher caloric reward than T.
alexandrinum . The honey bees ( Apis sp.) were attracted to M. sativa during early
hours of the day at peak periods of nectar production but after 1100 h onward foraging
populations shifted to T. alexandrium due to reduction in quantity of available rewards
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from M. sativa . Evidently, pollinators even prefer low rewarding flowers, when high floral
rewards are not available or the nearly resources are depleted. A. florea visited flowers
with low caloric rewards whereas A. dorsata preferred those with high rewards. This
behaviour was largely guided by their energy demands. Sunflower ( Helianthus annuus )
attracted almost all type of pollinators. Though the caloric reward per flower is low yet
each bee species including X. fenesterata and A. dorsata are able to maintain energy
balance. Since flower head with plateform provides no barrier for the landing of foragers,
the energetic cost is reduced due to temporarily suspension of hovering flight, and large
number of flowers can be visited in rapid succession. Generally, the smaller flowers with
little nectar are unattractive to large hovering animals such as hummingbirds and sphinx
moth which probably cannot suffice their energetic demands. However, insects such as
bumble bees, which land on inflorescences of Spiraea latifolia L. (Rosaceae) and
Solidago canadensis L. (Asteraceae) are still able to maintain an energy balance
despite minute amount of nectar in florets, because the energy expended in walking
from one flower to another is 100 times less than an equivalent period of flight and
because the flowers can be visited in rapid succession (Henrich and Raven, 1972).
Similarly, Luffa cylindrica flowers were visited by almost all kinds of bee pollinators
because the flowers are large with open nectaries and easily accessible to each type of
pollinator irrespective of the body size.
The solitary bees in contrast to social bees have far less energy demands as they
need not to incubate brood or support nestmates. However, it is essential for solitary
bees that foraging profit should exceed some minimum threshold value. Furthermore,
emergence pattern of solitary bees was synchronized with their specific host plants
(Sihag, 1983, 1984). The emergence of Megachile lanata synchronizes with the blooming of Cajanus. cajan, which is highly profitable for all the bees. Similarly L. cylindrica is
visited by all the solitary and social bees and is highly profitable. During March-May,
solitary bees mostly forage on M. sativa, P. aculeata, P. glabra, H. annuus and C. cajan.
Foraging on these crops is also highly profitable for all the bees excepting X. fenesterata
which rarely visited M. sativa flowers. In general, solitary bees were adapted behaviourally,
morphologically and physiologically to their specific host plants (Linsley et al. ,1963;
Strickler, 1979; Sihag 1988). Interestingly, M. sativa has to compete with P. aculeata for
pollinators (Sihag, 1982b). The pollinators are more attracted to P. aculeata and
because the latter provides relatively more caloric rewards. Further, ultra violet
reflectance pattern of P. aculeata flowers is more attractive to bees (Jones and Buchmann,
1974). However, the contention of Jain and Kapil (1980) that attraction of pollinators to
the latter plant is due to the presence of maltose in their nectar does not find a support,
because according to Rowley (1976) it is not a primary product of nectar yielding plants
but mainly arises due to glucophilic enzymes introduced by the insects or by fungal/
bacterial contamination. Therefore, to assign the floral attractiveness to this foreign agent
seems to be inappropriate.
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Suggested Readings
Abrol, D. P. 2011. Foraging. In : Howard R. Hepburn and Sarah E. Radloff (eds). Honey
bees of Asia. Springer Germany pp. 257-292.
Abrol, D. P. and R. P. Kapil. 1991. Foraging strategies of honeybees and solitary bees
as determined by nectar sugar components. Proc. Indian Natn. Sci. Acad.B
57 (2) : 127-132.
Abrol, D. P. 1986a. Time and energy budgets of alfalfa pollinating bee, Megachile nana
Bingh and M. flavipes Spinola (Hymenoptera: Megachilidae). Proc. Indian Acad.
Sci. (Anim. Sci.) 95 : 579-586.
Abrol, D. P. 1986b. Ecophysiological adaptations between pollinating bees and their
flowers. Environ. Ecol . 4 : 161.
Abrol, D. P. 1986c. Metabolic expenditures of Megachile nana Bingh and M. flavipes
Spinola (Hymenoptera::Megachilidae). J.Anim.Morphol. Physiol . 33 : 107-112.
Abrol, D. P. 1987. Activity time budgets and pollination potential of Apis cerana indica
workers. Environ. Ecol. 5 (4) : 707-709.
Abrol, D.P. 1989. Energy intake and expenditure in Andrena ilerda and A.leaena
(Hymenoptera : Andrenidae). Korean J. Apic . 4 : 41-47.
Abrol, D. P. 1990a. Energetics of nectar production in some apple cultivars as a
predictor of floral choice by honeybees. Trop. Ecol. 31(1) : 116-122.
Abrol, D. P. 1992a. Bioenergetics in bee flower interrelationship- An analysis of foraging
behaviour. Korean J. Apic. 7(1) : 39-66.
Abrol, D. P. 1992b. Energetics of nectar production in some strawberry cultivars as a
predictor of floral choice by honeybees. J. Biosci. 17(1) : 41-44.
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FACTORS RESPONSIBLE FOR POLLINATORS DECLINE
WITH PARTICULAR REFERENCE TO PESTICIDES
R. K. Saini
Department of Entomology
CCS Haryana Agricultural University, Hisar
Arthropods as a group have been very successful organisms on this planet, comprising over half of all the higher life forms. However, the expanding human population has
led to elimination of many arthropod species through the mechanisms of deforestation,
conventional farming, residue burn methods in the tropics, habitat fragmentation, excessive use of pesticides, etc.
Among the pollinators, the importance of bee pollination in human nutrition is immense and very difficult to quantify. It is commonly believed that about one third of
human nutrition depends on bee pollination. Pollinators help in sexual reproduction of
many plants, by ensuring cross-pollination, essential for some species, or a major factor in ensuring genetic diversity for others.
Studies are insufficient to quantify the effects of pollinator decline on wild plants and
wild life that depend on them for feed. Some plants species are endangered because
they have lost their normal, native pollinators because of displacement by invasive honey
bees. When honey bees compete with native bee species, a decrease in the honey bee
population may be beneficial to native plants and pollinators.
POSSIBLE CAUSES OF POLLINATOR DECLINE
Rapid transfer of parasites and diseases of pollinator species around the world
increased international commerce has caused spread of diseases such as American
foulbrood and chalkbrood, and parasites such as varroa mites, acarina mites, and the
small African hive beetle to new areas of the world, causing much loss of bees in the
areas where they do not have much resistance to these pests. Imported fire ants have
destroyed ground nesting bees in wide areas of the southern US.
Loss of habitat and forage
Use of farm machinery like large tractor mounted rotary mowers may make farms
and roadsides look neater, but they remove bee habitat at the same time. Similarly,
some old crops such as sweet clover and buckwheat, which were very good for bees,
have been disappearing. Increasing urbanization has also destroyed former areas of
pollinator habitat.
Nectar corridors
Migratory pollinators require a continuous supply of nectar sources to gain their
energy requirements for the migration. In some areas development or agriculture has
disrupted and broken up these traditional corridors, and the pollinators have to find alternative routes or discontinue migration.
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Nest destruction
People have often negative views about bees. A search for carpenter bees on the
Internet primarily yields information on removal rather than information regarding bees in
a positive light. Recent hysteria regarding killer bees has contributed to these views.
Light pollution
Artificial lights interfere with the navigational ability of many moth species. Moths
are important pollinators of night blooming flowers and moth disorientation may reduce
or eliminate the plants ability to reproduce, thus leading to long term ecological effects.
This is a new field and this environmental issue needs further study.
Competition with invasive honey bees
Many native pollinators decline in population when faced with competition from invasive honey bees. For example, the western honey bee is invasive in the United States.
The wild population consisting entirely of feral bees escaped from European bee colonies imported to fertilize non-native, old-world crops.
Air pollution
Researches show that air pollution from automobiles and power plants has been
inhibiting the ability of pollinators such as bees and butterflies to find the fragrances of
flowers. Pollutants such as ozone, hydroxyl, and nitrate radicals bond quickly with volatile scent molecules of flowers, which consequently travel shorter distances intact. Thus,
there is a vicious cycle in which pollinators travel increasingly longer distances to find
flowers providing them nectar, and flowers receive inadequate pollination to reproduce
and diversify.
Misuse of Pesticides
Pesticides are used in agriculture, horticulture and in field and forest situations to
control a wide range of insect pests and weeds. However, they can severely impact
pollinators. Yet such applications are frequently done, with little enforcement of the bee
protection directions. Pesticide misuse has driven beekeepers out of business, but can
affect native wild bees even more, because they have no human to move or protect them.
Many forestry insecticides have been found to have lethal or sublethal effects on natural
pollinators (Helson et al. , 1994), and broad spectrum insecticides used for grasshopper
control in rangelands impact non-target insects (Alston and Tepedino, 2000). Actual
damage to bee populations is a function of toxicity and exposure of the compound, in
combination with the mode of application.
Bumble bee populations are facing danger in cotton growing areas, since pesticides
are applied through out the blooming season where bees are foraging. Similarly, aerial
applications for controlling mosquitoes, grasshoppers and other insects leave little room
for safety of wild insect pollinators where they can reproduce and multiply. Likewise,
treating of lawns with pesticides and removing every type of plant other than grass also
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make a hostile environment for bees, butterflies and other pollinators. Much of the research data on the effects of insecticides on species of wild bees is available on the
alkali bee, Nomia melanderi , and the alfalfa leafcutting bee, Megachile rotundata, has
been the most extensive to date. The alfalfa leafcutting bee can be safeguarded by
storing the nest units in a cool room or root cellar for a few days while the field is being
treated. Nests with females in the ends of the tunnels can be moved at night. Leafcutter
nest shelters can be built to be covered or closed during insecticide applications to
reduce the drift of dusts or sprays into the nest structures. Do not allow insecticide
dusts or sprays to drift onto alkali bee nest sites or blooming crops on which these bees
are foraging. Do not spray chemicals on or burn adjacent wild land or fence rows around
red clover, cranberry, or other berry crops. Such areas provide nest sites for bumble
bees that aid materially in pollinating these crops. In this chapter, more emphasis will
be laid on bees.
CAUSES OF BEE POISONING
Most of the poisoning occurs when insecticides are applied to crops during the
blooming period when bees are attracted to the flowers or to secretions from extra-floral
nectaries. These are the worker bees which are primarily affected by pesticides. The
symptoms of poisoning can vary depending on the developmental stage of the individual
bee and kind of chemical employed. The larval stage is the most susceptible to
pesticide poisoning during development. House bees are usually poisoned by contaminated pollen which is collected in the field, brought back and stored in the hive. As
house bees are killed, there are fewer bees to tend the brood and further decline in
population results. Most times, field bees are killed by contact with pesticides in the
field, but other times they collect contaminated nectar and pollen and contribute to
poisoning their sisters in the colony. If field bees are killed, then young bees are forced
into the field earlier than normal, disrupting and thus disorienting the colony. While
foraging, field bees may range as far as two to five miles from a colony. They usually
seek nectar and pollen systematically, not randomly, and once a food source is found,
bees prefer to work that particular source to exhaustion before changing plants. This
kind of resource partitioning by bee colonies accounts for the inconsistency observed
many times between colonies undergoing pesticide poisoning in the same location. The
bees are not all working the same plants and so some are affected more than others.
Often it is those bees with established flight patterns located in an area before a pesticide is applied that are most damaged.
The other hazards are :
Toxic pesticides drift from their point of application into nearby crops or weeds that
are in bloom or across apiaries.
Contamination of flowering cover crops associated with insecticide treated orchards.
Collection of insecticide contaminated nesting materials, for example, leaf pieces
collected by leaf-cutting bees.
Drinking or touching of pesticide contaminated water on foliage or flowers by the
bees.
Insecticide dusts clinging to foraging bees.
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Bee Poisoning Symptoms
Only one readily recognized symptom is good evidence of pesticide damage; the
presence of many dead or dying bees nears a colony's entrance. In a short period of
time, however, these dead bees may dry up and the remains be blown away and eaten
by ants or other scavengers. A beekeeper, therefore, who visits his yards only occasionally may not see these dead bees and thus not be aware that his colonies have been
poisoned.
The most common symptom of bee poisoning is the presence of many dead or dying
bees near a colony's entrance. In a short period of time, however, these dead bees may
dry up and the remains be blown away and eaten by ants or other scavengers. A beekeeper, therefore, who visits his yards only occasionally may not see these dead bees
and thus not be aware that his colonies have been poisoned. Dead adult bees, in general, have their wings unhooked and at odd angles to their body; the proboscis fully
extended; and hind pair of legs outstretched behind them. Another common symptom is
the lack of foraging bees on a blooming crop that is attractive to bees. Aggressiveness
in bees may be caused by most pesticides. OP and OC insecticides commonly cause
stupefaction, paralysis and abnormal activities in bees. Bees may perform abnormal
communication dances. Disorganized behaviour pattern may lead to lack of recognition
of affected field bees by guard bees. Some other symptoms of bee poisoning could be
regurgitation of the nectar from the bees' honey stomach (often caused by
organophosphorous insecticides), confusion and fighting at the entrance to hives, slow
moving or immobile bees which die in two or three days, dead brood in the comb or in
front of the hive queen death or replacement of queens in cases where the hive is severely disrupted by a pesticide.
Many bees poisoned with carbaryl or dieldrin slow down and appear as though they
had been chilled; such bees may take two to three days to die. Bee keepers familiar
with carbaryl poisoning quickly learn to recognize the "crawlers" that move out in front of
the hive but are unable to fly. In severe case, when insufficient numbers of adult bees are
left to cover the brood frames or to care for the brood, temperature and humidity control
in the brood area is lost and the brood die from chilling, overheating or starvation. In
some cases, only a few bees in the hive survive, or the entire colony may be dead.
Foragers returning to hive with pesticide contaminated pollen or nectar can cause
extreme agitation and death of a number of bees. Several such foragers can seriously
disrupt and damage the colony. Queen may behave abnormally. For example, it may lay
eggs in a poor pattern. Queen failure may occur within 30 days. Severely weakened or
queenless colonies will not live through the following winter.
Generally speaking, some pesticides can be made safer to honey bees by slightly
lowering the dosage. Conversely, by increasing the dosage only slightly the pesticide
may become highly hazardous to bees. It is emphasized that some pesticides are more
or less hazardous than one can anticipate from the laboratory data. Most of these are
pesticides which have very short or very long residual characteristics.
Neo-nicotinoids effects on bee poisoning
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Pesticide exposure has received significant attention and recently-published analyses of pollen from managed bees located near agricultural environments demonstrated
that many agricultural chemicals (including insecticides, miticides, fungicides and herbicides) are detectable in honey bee wax and pollen samples. Of the many compounds
detected, the neo-nicotinoid group has arguably received the most attention. These compounds act as nicotinic acetylcholine receptor agonists in insects, causing persistent
excitation of these receptors and eventually death. As a group, neonicotinoids possess
several key attributes that have facilitated heavy adoption in both agricultural and urban
environments, including low vertebrate toxicity and the ability to be translocated by
plants. Neonicotinoids are also persistent, offering the potential for a large window of
activity. Imidacloprid is a systemic neonicotinoid insecticide which acts as a neurotoxin
and interferes with the transmission of nerve impulses in insects by binding to specific
nicotinic acetylcholine receptors. Imidacloprid is implicated in honeybee colony collapse disorder. As a systemic pesticide, imidacloprid moves readily from the soil into
the leaves, flowers, fruiting bodies, pollen and nectar.
Fipronil
Fipronil acts by contact and stomach action on the insects. It is effective against a
variety of pests, but there are increasing concerns about its environmental and human
health effects. Its use has become problematic in France, where it has been proven
responsible for the drop in bee population, after bees became disoriented and unable to
return to their hives. It is one of the main chemical causes blamed for the spread of
"colony collapse disorder" among bees. It has been found by the Minutes-Association
for Technical Coordination Fund in France that even at very low non-lethal doses for
bees, the pesticide still impairs their ability to locate their hive, resulting in large numbers of forager bees lost with every pollen-finding expedition.
THE HONEY BEE MORTALITY PREDICTOR: A RAPID METHOD
The nomogram provides a quicker method of predicting the mortality of honey bees
from field applications of pesticides, which requires mathematical calculations. The method
is also useful for predicting potential hazards to honey bees when applying pesticides
for mosquito abatement and for pest control in forest, rangeland, recreational areas, and
home gardens.
COLONY COLLAPSE DISORDER
Colony collapse disorder (CCD) is a syndrome that is characterized by the sudden
loss of adult bees from the hive. While such disappearances have occurred throughout
the history of apiculture, the term colony collapse disorder was first applied to a drastic
rise in the number of disappearances of Western honey bee colonies in North America in
late 2006. Colony collapse is significant because many agricultural crops worldwide are
pollinated by bees.
Many possible explanations for CCD have been proposed, but no one primary cause
has been found. In 2007, some authorities attributed the problem to biotic factors such
as Varroa mites and insect diseases (i.e.pathogens including Nosema apis and Israel
acute paralysis virus. Other proposed causes include environmental change-related
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stresses malnutrition, pesticides (e.g. neonicotinoids and migratory beekeeping. More
speculative possibilities have included both cell phone radiations and genetically modified crops with pest control characteristics. It has also been suggested that it may be
due to a combination of many factors and that no single factor is the cause. The most
recent report (USDA - 2010) states that "based on an initial analysis of collected bee
samples (CCD- and non-CCD affected), reports have noted the high number of viruses
and other pathogens, pesticides, and parasites present in CCD colonies, and lower
levels in non-CCD colonies. This work suggests that a combination of environmental
stressors may set off a cascade of events and contribute to a colony where weakened
worker bees are more susceptible to pests and pathogens.
HOW TO REDUCE BEE POISONING
Following are some of the ways to help reduce bee poisoning :
Suggestions for Pesticide Applicators
Avoid applying insecticides that are toxic to bees on crops in bloom, including cover
crops in orchards and adjacent crops or interplants. Insecticide should be applied
only while target plants are in the bud stage or just after the petals have dropped.
Ground application is generally less hazardous than aerial application because less
drift of the pesticides occurs, and smaller acreages are treated at one time.
Certain chemicals may be used during late evening, night, or early morning when
bees are not actively foraging (generally between 6 p.m. and 7 a.m. Evening applications are generally less hazardous to bees than early morning applications.
Avoid using insecticides when temperatures are expected to be unusually low following treatment as residues will remain toxic to bees for a much longer time.
Do not dump unused dusts or sprays where they might become a bee poisoning
hazard.
Do not contaminate water. Bees require water to cool the hive and feed the brood.
Never contaminate standing water with pesticides or drain spray tank contents onto
the ground, creating puddles.
Use insecticides that are relatively non-hazardous to bees.
Select the less hazardous insecticide formulations. Dusts are more hazardous than
sprays of the same insecticide. Emulsifiable (liquid) formulations usually have a
shorter residual toxicity to bees than do wettable powders. Granular formulations
are low in hazard to bees.
Request the beekeeper to remove colonies from the area (or keep the bees confined
during the application period) before applying hazardous pesticides.
Suggestions for Growers
Before treating a field with pesticides, check for the presence of other blooming
plants and weeds which might attract bees. In many instances bees have been killed
even though the crop being sprayed was not in bloom. Many times these attractive
blooms can be mowed or otherwise removed. Likewise, mow or beat down orchard
cover crops before applying sprays hazardous to bees.
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Sevin used as a fruit thinner can be hazardous if cover crop blooms become contaminated.
Learn the pollination requirements of the crops you raise.
When insect pests have been damaging a crop every season, use a preventive program of early season application before pest population increases. Such a program
is usually less dangerous to pollinating bees and other beneficial insects as well.
Learn about the beekeeper's problems with chemical poisoning and enter into mutually advantageous agreements to best produce bee-pollinated crops.
Suggestions for Beekeepers
Never leave unmarked colonies of bees next to orchards or fields. Post your name,
address, and phone number in printing large enough to be read at some distance in
all apiaries so you can be contacted readily to move the colonies when hazardous
sprays are to be applied.
Do not move hives back into fields treated with hazardous insecticides until at least
48 to 72 hours after the application. About 50 to 90 percent of the killing of bees by
insecticides occurs during the first 24 hours after application.
Choose apiary sites that are relatively isolated from intensive insecticide applications and not normally subjected to drift of chemicals.
Develop mutually beneficial agreements with growers concerning pollination service
for prudent use of pesticides.
If beekeepers are notified in advance of application, colonies can be moved or loosely
covered with burlap or coarse cloth to confine the bees and yet allow them to cluster
outside the hive under the cloth to protect them from the initial hazards of an insecticide. Repeated sprinkling each hour with water prevents overheating. Do not screen
or seal up colonies and do not cover with plastic sheeting. This can result in overheating, leading to bee suffocation and death. This method works; however, most
beekeepers find it impractical.
SUSTAINING POLLINATORS' DIVERSITY
Conservation and restoration efforts
Efforts are being made to sustain pollinator diversity in agro- and natural ecosystems by some environmental groups. Establishment of wildlife preserves, and encouragement of diverse wildlife landscaping rather than monoculture lawns, are examples
of ways to help pollinators.
Alternative pollinators
Honey bees are usually the most widely chosen insects in most managed pollination situations. However, they are not the most efficient pollinators of some flowers.
Alternative pollinators, such as for example, leafcutter, and alkali bees in alfalfa
pollination and bumblebees in greenhouses for tomatoes are used to augment and in
some cases replace honey bees. A wide variety of other bees that are specialist pollinators (some only using one plant species) can be found in the environment. However,
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most of these alternative insects have their importance as pollinators but their relationships with plants are yet little known.
In the US, some think that other pollinators will in time replace the lost honey bees,
blamed on introduced acarine and varroa mites, but general pollinator decline was already happening before these entered the picture. Furthermore, pollinators cannot be
exchanged on a one-for-one basis. They are not all equal. Some are generalists, some
are specialists. Some are brawny; some are feeble. Some have long tongues; some
short. Some work at colder temperatures than others. Bees may deliberately collect
pollen, but have different collection techniques, which can greatly affect their efficiency
as pollinators.
Flowers are frequently specifically adapted to one pollinator, or a small group of
pollinators because of floral structure, color, odor, nectar guides, etc. Proposed alternative pollinators may not be physically capable of accomplishing pollination, or they may
not be attracted to the flower of that plant species, or they may rob nectar by cutting
sepals, thus avoiding pollination. Understanding the pollination needs of a species is
vital to understanding of a plant species
Increasing public awareness
There are international initiatives (e.g. the International Pollinator Initiative (IPI)) that highlight
the need for public participation and awareness of pollinator, such as bees conservation. The
steady increase in beekeeper migration (for pollination service on agricultural crops) has
masked the issue of pollinator decline from much public awareness.
Suggested Readings
Alston, D. G. and Tepedino, V. J. 2000. Direct and indirect effects of insecticides on
native bees. In Grasshopper Integrated Pest Management User Handbook
(Technical Bulletin No.1809), edited by G. L. Cuningham and M. W. Sampson,
Washington DC : US Department of Agriculture, Animal and Plant Health
Inspection Services.
Helson, B. V., Barber, K. N. and Kingsbury, P. D. 1994. Laboratory toxicology of six
foresting insecticides to four species of bees/ Hymenoptera: Apoidea). Archives
of Environmental Contamination and Toxicology 27 : 107-114.
Johansen, C. A. and Mayer, D. F. 1990. Pollinator Protection - A Bee and Pesticide
Handbook. Chesire, CT : Wicwas Press.
Kremen, C., Williams, N. M. and Thorp, R. W. 2002. Crop pollination from native bees at
risk from agricultural intensification. Proceedings of the National Academy of
Sciences 99 : 16812-16816.
Krupke C. H. , Hunt,G. J. Eitzer, B. D., Andino, G. and Given, K. 2012. Multiple Routes
of Pesticide Exposure for Honey Bees Living Near Agricultural Fields. PLoS ONE
7 (1) : e29268. doi : 10.1371/journal.pone.0029268.
Riedl, H., Johansen, E., Brewer, L. and Barbour, J. 2006. How to reduce bee poisoning
from pesticides. A pacific Northwest Extension Publication PNW 591, Oregan
State University.
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ROLE OF MELISSOPALYNOLOGY IN BEEKEEPING
G. S. Yadav and Hasansab A. Nadaf
Department of Entomology,
CCS Haryana Agricultural University, Hisar
Pollen analysis of honey, or melissopalynology, is of great importance for quality
control. Honey always includes numerous pollen grains (mainly from the plant species
foraged by honey bees) and honeydew elements (like wax tubes, algae and fungal spores)
that altogether provide a good fingerprint of the environment where the honey comes
from (Werner et al ., 2004).
Pollen analysis can, therefore, be useful to determine and control the geographical
and botanical origin of honeys even if sensory and physico-chemical analyses are also
needed for a correct diagnosis of botanical origin These studies have made it possible to
ascertain, on a rigorous, scientific basis, the apicultural importance of the different botanical species, whereas previously this evaluation was the fruit of general field observations. Flower nectar always contains greater or lesser quantities of pollen and this pollen can then be traced in the honey sediment. Identification of these pollens, estimation
of the percentage in which they are present and the eventual identification of elements
probably indicative of honeydew, make it possible to trace the botanical species gathered with far greater precision than can be obtained with direct observations. With direct
observation it is only possible to ascertain whether a species is more or less intensely
visited by bees, but not the extent to which it contributes to honey production.
Qualitative melissopalynological analysis
This kind of analysis consists in recognizing the different fungi imperfecti contained
in the sediment and in evaluating the respective percentages of each element. In most
cases this is sufficient to determine the botanical and geographical origin of honey. It is
impossible to discover the botanical origin of honey obtained by pressing, because the
sediment is enriched with the contents of the pollen cells. Caution is needed when
identifying the botanical origin of Calluna honey because the extraction technique used
for this honey results in abundant sediment. Ten gram of honey is dissolved in 20 ml of
water at 40°C and then centrifuged for 5' at 2,500 rpm and settled; the sediment
is recovered in 10 ml of distilled water and is centrifuged again and then settled; the
sediment is then collected with a Pasteur pipette and set onto an object slide where it
dries at 40°C; it is then included in glycerinated jelly, covered with a microscope slide.
If the type of honey to be analysed contains many colloids it is better to use acidulous
water with 5 g/l of sulphuric acid, rather than pure distilled water. The next step is the
microscopic analysis of the compound and identification of its component elements with
the help of reference compounds.
When identifying pollens it is often not possible to ascertain the exact species and
sometimes even the genus is uncertain; in these cases more general categories, based
on groups, shapes, and types are used. The number of granules examined depends on
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the degree of precision required. For an indicative sample evaluation the computation of
about 100 pollen grains should be sufficient. It is necessary to count 200-300 pollen
grains to determine the frequency classes.
The following nomenclature is used when determining the frequency classes :
Very frequent pollen
>45%
Frequent pollen
16-45%
Isolated pollen
4-15%
Rare pollen
<3%
For a precise percentage calculation 1000-1200 pollen grains have to be counted
(Vergeron, 1964) and the following terms are adopted:
Predominant pollen
Accompanying pollen
Important isolated pollen
Isolated pollen
>45%
16-45%
4-15%
<3%
A nectar honey is considered to be of a certain species if the pollen of this species
exceeds 45% of the total. If there is no predominant pollen then this kind of honey is
classified as multifloral.
Quantitative melissopalynological analysis
This kind of analysis involves the evaluation of two different parameters: the total
sediment volume and the quantity of fungi imperfecti per honey weight unit.
The determination of the total quantity of sediment per weight unit makes it possible
to ascertain how a type of honey was produced and whether or not it contains any
foreign matter; it can also be useful in identifying adulterated honey. The method used is
as follows : 10 g of honey are dissolved in 20 ml of water at 40°C and centrifuged for 10';
the supernatant liquid is carefully sucked up leaving only 1-2 ml which is then shaken
and decanted in a graduated centrifuge tube of the right size, so as to recover all
the sediment; it is then centrifuged again for 10' and the sediment volume read off the
graduated tube.
The determination of the absolute number of fungi imperfecti per unit of honey weight
consents a more precise interpretation of qualitative analysis results in the case of
honey varieties with under- and overrepresented pollen. This is especially the case when
both types of pollens are present in the sediment.
Reference materials
Palynological analysis requires a good collection of reference materials (Fig.). These
include pollen samples taken from the different botanical species and the laboratory
equipment needed for undertaking qualitative and quantitative analysis. There are two
methods of sample pollen preparation: the acetolytic one and the one prescribed by the
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International Commission for Plant-Bee Relationship (Louveaux et al. , 1978). With the
acetolytic method (flowers or anthers), the cytoplasm and the intina of the granules are
destroyed; the exina is made darker by the acetolytic treatment and its structural and
sculptural details can be seen clearly. With the second method, it is possible to
conserve the cytoplasm of the granules which sometimes presents useful typical
features, but sporodermis details are not seen clearly.
In melissopalynology, a magnification of 400X is normally sufficient to discover the
botanical source of any given honey; specialized analysis is only necessary in doubtful
cases, i.e. when one needs to know more about pollens that are difficult to classify
(1000X). It is practically impossible to prepare a pollen collection which covers all botanical species. Pollen shapes, however, are relatively homogeneous within any given
botanical family and so a pollen collection in which every family is represented, which
contains the most widely diffused genera and species and the anomalous and typical
pollen shapes, is perfectly adequate. If a researcher wants to study foreign honeys as
well as domestic ones, the collection has to be increased: at least one sample of the
better-known shapes, types, groups or genera of honey should be included in it.
Pollen analysis is an indispensable method to authenticate honey origin and characteristics. It is very effective to determine and control the geographical origin of honeys
and it also provides information about other important quality aspects. It also contributes, together with sensory and physicochemical analyses, to the determination and
control of the botanical origin of honeys. For these purposes, it is not necessary to
determine all existing pollen types in the honey and, on the other hand, the natural
variability of honey itself makes it difficult to define extremely precise references or
limits for the pollen spectrum of a given honey type. Indeed, the main critical point of
melissopalynological analysis remains the correctness of pollen identification and the
subsequent interpretation of the results. These require from the analyst a considerable
experience in melissopalynology and a good general knowledge of this amazing product
that is honey. The results of melissopalynological analysis, however reliable, cannot
guarantee absolute precision. In conclusion, melissopalynology, like other sciences
investigating biological phenomena, where it is often difficult to evaluate the variables,
can make no claim to be a mathematical science.
Suggested Readings
Louveaux, J., Maurizio, A. and Vorwhol, G. 1978. Methods of Melissopalynology.
International Bee Research Association. Bee World 59 (4) : 139-157.
Vergeron, P. 1964. Interpretation statistique des resultants en matiere d'analyse pollinique
des miles. Annual Abeille 7 (4) : 349-364.
Werner Von Der Ohe, Livia Persano Oddo, Maria Lucia Pian,Monique Morlot and Peter
Martin. 2004. Harmonized methods of melissopalynology. Apidologie 35 : S18S25.
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Robinia pseudoacacia (False Acacia)
Rubus spp.
Trifolium spp.
Zea mays (maize)
Eucaliptus spp.
Citus spp.
Aegiceras corniculatum (Mangrove)
Aesculus indica
Allium cepa
Brassica oleraceae
Brassica rapa
Calandula officinalis (Marigold)
Calistema citrinus (Bottle brush)
Coriandrum sativum (Dhania)
Coffeae arabica
Citrus aurantium (Malta)
Calluna vulgaris (Heather)
Campanula punctata (Bell flower)
Eugenia spp. (Bhedas)
Helianthus annus (Surajmukhi)
Morus alba (Mulbery)
Musa rubra (Banana)
Prunus spp.
Pyrus spp.
Dacus
carota
Medicago
sativa
(Lucerne)
Gossypium
hirsutum
(Cotton)
Azadirachta
indica
(neem)
Celtis spp.
Celtis spp.
SIGNIFICANCE OF COMPUTER USAGE IN BIOLOGICAL SCIENCES
A. K. Chhabra*, Pratiksha Mishra and Ashish Jain
Department of Genetics and Plant Breeding,
CCS Haryana Agricultural University, Hisar 125 004, Haryana
Teachers and researchers must be educated well to adapt to present day technology. Almost everyone in an institute is accustomed to the use of computers today at
least for word processing and internet usage. But there are very few education sites
where they are taken beyond this point of computer usage. Although not everyone need
to know programming, computer graphics, hypermedia and so on, they should at least
be given some insight into the possibilities available with computers today. Scientists
and teachers must develop skills to use computers efficiently in day to day work and
their respective scientific and academic area.
In this brief note about usage of modern computer skills in biological sciences and
presentations would be discussed to benefit the trainees enabling them to make efficient use of the computer facilities they have at their home place. Person intended to
learn presentation tools must have some idea about the following areas/software.
Most commonly operating systems in use in India are: different versions of Windows
OS like Windows XP, Windows Vista and Windows 7. What Microsoft Windows 95 did
to PC industry 16 years ago, the upcoming Windows 8 is set to do the same! At least
that's what the world's biggest software maker, Microsoft, is hoping.
Making presentations through PowerPoint
(MS Office 2007 or later)
Word Processing (MS Word)
Data feeding and processing (MS Excel)
Scanning of picture and text (Scanner)
Labeling of pictures (MS Power Point,
Photoshop etc.)
Editing of pictures (Photoshop, Corel etc.)
Creation of web pages (Front Page, MS
Publisher etc.)
Use of digital camera
Creation of animated gifs (Animation Shop2)
Preparing Electronic manuals (CD/DVD
Writer)
Using multimedia (Audio, Video accessories)
Sound Recording (Mike & sound-proof room)
Editing documentary movies (Windows
Movie Maker)
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Use of internet and e-mails (internet explorer, Google chrome etc.)
Searching web for the topic of choice (Search Engines: Google, AltaVista etc.)
Creation of Hyper-books (Online teaching/education)
Creating Exercise Environment
Creating interactive CD media
Creative imagination
VCD cutter, Sound editor etc.
A Computer Aided Learning Package includes following stuff :
Equipments
1. P IV Desktop /laptop Computer (Windows Vista/7 is preferred), i3-i7 computers, 2-4
GB RAM
2. High resolution fast speed Scanner
3. Digital Camera with optical zoom (6-14 mega pixels)
4. Web camera
5. LCD Projector
6. Projection screen
7. Multimedia with speakers and headphones.
8. LAN
9. Smart class rooms if available.
Softwares/websites/cards etc.
1. Office 2007 or higher version (2010)
2. Windows Vista /7/8
3. Gif animator
4. Voice recorder, Converter
5. Superegoo
6. CD writing software (Nero)-may be write scribble
7. Video card
8. TV tuner card
9. Flash media player etc.
Write scribble DVDs can be used
to prepare CD Labels using Write
Scribble DVD Writers to give
them professional look and
permanent documentation.
10. Google Translate
11. Picasso
12. Google Document
13. YouTube
14. AuthorStream
15. Google Family etc.
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Creation of presentation :
Simple presentation (text only)
Narrated Presentation
Hyper linked presentation
o Hyper linking with MS office files
o Hyper linking with Picture files
o Hyper linking with Macromedia flash files
o Hyper linking with Gif animations
o Hyper linking with media files
o Hyper linking within ppt files
o Hyper linking with internet files (online animated files)
Autorun CDs/DVDs (explained in details somewhere else in this chapter)
Web-based browsable CDs
BRIEF DISCRIPTION ABOUT SOME SPECIALIZED SOFTWARES (FREEWARES)
Macromedia Flash
Originally a web animation tool, Macromedia Flash has quickly become a standard
for creating a dynamic, interactive experience. The Flash authoring program can be
used to create animations, games, websites, standalone modules, and also has audio
and video capabilities.
Macromedia Fireworks
Macromedia Fireworks is an image-editing program geared specifically towards producing web images. It is often used to create JavaScript effects as well for the program
will generate both JavaScript and html to handle different sorts of image interactions.
Macromedia Dreamweaver
With Macromedia Dreamweaver you can easily create both websites and web applications. Aside from a WYSIWYG editor, Dreamweaver also has extended hand-coding
functionality and supports the new XHTML standard as well as many other scripting
languages including Coldfusion, PHP, and ASP.
Macromedia Freehand
Comparable to Adobe Illustrator but with far fewer options. Macromedia Freehand is
a vector illustration tool. Whereas Fireworks is Macromedia's editor for bitmapped images, Freehand works in a total vector environment.
Adobe Premiere
Adobe Premiere is a video editing software package with the ability to layer, crossfade
and effects. Voiceovers, environmental sounds, and music can be imported and mixed
with Premiere's limited audio support. With support for both digital and analog video
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capture and the ability to output in a number of different formats Premiere is one of the
most widely used video editing applications available.
Adobe Photoshop CS2
Adobe Photoshop is a near-perfect image editing tool. Photoshop can be used for both
print and digital and has support for all major image formats. Far superior to Macromedia
Fireworks, Photoshop is the best image editing application there is.
Adobe Illustrator
One of the major strengths of Adobe Illustrator is the extent to which it resembles
Photoshop. As a vector-image editor, it shares the same relationship with Photoshop
that Freehand has with Fireworks. While the Fireworks/Freehand combination is an
excellent choice for trainees, those in need of more options and an overall deeper
experience should go with Photoshop/Illustrator.
Adobe Photoshop Elements
A pared-down version of Adobe's excellent Photoshop image editing software. While
this program does retain many of the features of it's parent, it is intended for light editing
by those who might be confounded by the amount of options in Photoshop. Excellent for
editing photographs.
Adobe Acrobat Reader and Writer
Adobe Acrobat can be used to author the Portable Document Format [PDF] or convert other documents created in Microsoft Word or other word processing packages into
PDF documents. The advantage of having a document in PDF format is that it can be
read on any machine that has the Adobe Acrobat Reader installed [a free download] and
it also retains the quality of the original document.
Adobe GoLive
Comparable to Macromedia Dreamweaver, Adobe GoLive is a website creation tool
allowing both WYSIWYG and straight code editing capabilities.
Adobe InDesign
Adobe InDesign is a page layout software package similar in functionality to Microsoft
Publisher and is used for print layout in the creation of brochures, pamphlets, and
flyers.
Adobe LiveMotion
Adobe LiveMotion is similar to Macromedia Flash as it allows for the creation of
animation and interactive content.
Microsoft Word
Part of the Microsoft office suite, Word is a word processing and document creation
utility.
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Microsoft Access
Part of the Microsoft Office suite, Access is a database creation and management
utility.
Microsoft Visio
Microsoft Visio is used to map web site architectures. A great tool for taking a website
apart visually in order to either get a grasp of how it works or to plan it's reconstruction.
Microsoft FrontPage
Part of the Microsoft office suite, FrontPage is a website creation utility. While
FrontPage can be compared to both macromedia, Dreamweaver and Adobe GoLive, it is
definitely the poorest of the bunch.
Microsoft Excel
Part of the Microsoft office suite, a spreadsheet creation and management utility.
Microsoft Publisher
Microsoft publisher is primarily used for print layout in the creation of brochures,
pamphlets, and flyers.
Microsoft PowerPoint
Part of the Microsoft office suite, PowerPoint is used to create slideshows for presentations.
Scansoft Omnipage Pro
Scansoft Omnipage Pro is an optical character recognition program with the ability
to read scanned documents and translate the letter shapes from the scanned image into
type to be used in a word processor.
ELECTRONIC MANUALS
Electronic manual means information in the digital form that can be read on any PC
having capability of retrieving the information written on the storage media (floppy/zip
disc/CD/DVD/Pen drive etc.). A demonstration of an electronic manual being prepared
for UG and PG students of Fenetic and Plant Breeding will be given in the training. This
manual can be used for various purposes: delivering lectures, seminars, publishing proceedings of seminar/symposia etc., Publishing high quality pictures in digital form saves
resources and its distribution is faster and economical than hard bound big books.
Preparation of such manuals requires little knowledge of some of the software listed
above. Moreover, internet links can also be provided on the CD which can be directly
accessed to get up to date information while being on the internet.
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INTERNET
World Wide Web as an Aid to Search and Explore New Information of global Importance: The World Wide Web (www) is a big part of the Internet; to understand the World
Wide Web, one first has to understand its home - the Internet. The Internet is the global
"Network of Networks," linking thousands of computer networks together allowing communication with millions of computer users and access to resources from around the
world. The Internet is an enormous library or collection of libraries through which one
can access information on any topic of concern. It doesn't matter what type of computer
is used for connection to the Internet, a virtually limitless wealth of resources is available for everyday use. The Internet and the World Wide Web are (or will soon become)
most important components for a research institute, college or school. The use of the
internet also provides opportunities for inquiry-based learning through search engines
and specially designed sites to extract specific information. Various important scientific
journals also offer such opportunities to their users. Internet is the largest province for
researchers and academics in laboratories. Now, the Internet is everywhere, it is growing rapidly worldwide and has gained widespread popularity relatively recently.
Google Family
List of Search Engines Worldwide
The search engines are all excellent choices to start with when searching for
information.
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Google
: http://www.google.com
AllTheWeb.com (FAST)
: http://www.alltheweb.com Yahoo
: http://www.yahoo.com
MSN Search
: http://search.msn.com
Lycos
: http://www.lycos.com
Ask Jeeves
: http://www.askjeeves.com
AOL Search
: http://aolsearch.aol.com/ (internal)
: http://search.aol.com/ (external)
Teoma
: http://www.teoma.com
WiseNut
: http://www.wisenut.com
Inktomi
: http://www.inktomi.com
LookSmart
: http://www.looksmart.com
Open Directory
: http://dmoz.org/
Overture
: http://www.overture.com/
AltaVista
: http://www.altavista.com
HotBot
: http://www.hotbot.com
Netscape Search
: http://search.netscape.com
Free Software from net
Internet is the best source to get many software called as Freeware. There are several sites where you can get them. The most important one is http://freedownload.com
and http://www.download.com
Practical Demonstrations
Practical demonstrations of each and every type of presentation discussed here in
would be given to the participants during this workshop to make them well versed with
the uses and applications of all the scientific computer tools.
We are living in a Computer Era. Technology is moving fast with an incredible speed.
To justify our existence, we have to keep pace with the growing technology and compete
the world. Computer usage is one area where sometimes most of us feel incompetent.
However, with little efforts and zeal to learn, we can master this area to make its full
use.
CREATION OF AN ELECTRONIC MANUAL
Being scientists/professors in the university, we have to
present our research findings in the workshops, present
papers in conferences and symposia or teach in the class
rooms or impart trainings to the farmers. It needs creation of
different presentations for each purpose even if the topic is
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same for all. This hassle may be avoided if we create one "Electronic Manual" on each
topic of concern. The manual thus prepared may be used for presentation purpose on
any platform.
What is an Electronic Manual?
An electronic manual is creation of an auto run CD/DVD on a particular topic which
is interactive, informative and having many user friendly options to play in front of audience (conference/symposia/class rooms/field trainings etc.). This consists of an index
page (main page like a web page) and several other files linked to it. It may have music
in its background or may be a silent video. This may be in the form of CD or DVD or any
other storage media to play on the any computer.
Steps to create an electronic manual
1. Creation of text : Type the contents and the detailed text in MS word and divide it
on different slides for presentation in PowerPoint.
2. Collection of pictures and movie/video clips : Bring together all the video clips in
a folder to be used in the CD. The movies may be the original recordings, documentary, files downloaded from the internet etc. The care must be taken that these are
not protected by any copyright or ensure that permission has been obtained from its
author before publishing them in your electronic manual.
3. Collection of Audio clips : Collect all the audio clips that you want include in the
CD. These may be original recordings (compatible format with PowerPoint), recording through sound recorder of windows XP or may be time lapse recording through
windows vista.
Media files may also be created
using combination of still and movie
pictures in Windows Movie Maker of
Windows Vista. It also has many
options for sound editing and sound
recording. For conversion of file
formats, a number of free softwares
are available on the internet that can
be downloaded free for editing and
splitting or joining the audio-video
files.
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4. Making a master folder in the computer : A master folder on the computer desktop is created. All the files (Sr. No. 1-3 above) are transferred to this master folder.
5. Creation of PowerPoint shows : Using the text, prepare a PowerPoint show following instructions to insert pictures/movies/video clips etc. This file may be saved
in the master folder as a Main.ppt file.
6. Inserting play buttons : Play buttons (Play, Next, Previous, Previously Played and
Home) may be added on right of left side of the each slide (by placing in the master
slide). These would assist in smooth play of the CD.
7. Inserting hyperlinks : Audio, Video, Movie clips, or any other file (for which operating programme is available in your computer) and even internet URLs/links may be
added using hyperlinks options. Save the PowerPoint file in the Main.pps mode.
A quiz session may also be incorporated before finalizing the PowerPoint Show. This
may be used later by the user to evaluate himself/herself on the specified topic.
8. Creation of an Autorun file : An autorun file using the name of PowerPoint file
(.pps) is created to autorun the CD. This file is not recorded if you are going to use
Pack and Go option of the PowerPoint to save your files.
9. Copying files
a. Copying on the CD : All the files of the master folder are copied on the CD/DVD using
standard CD Copying programmes (Nero/
Roxio CD Writer / Windows default
programme). The care must be taken that
files are saved without the master folder.
b. Copying on Pen Drive : The PowerPoint file
is saved using the option pack and go. This
zipped folder is then transfer on the
computer to be used for presentation. The
zipped folder is unzipped. This facilitates the
validation of hyperlinks on the computer
which was not used for the preparation of
PowerPoint file. The window shown here
appears in Pack on CD Options in Microsoft
PowerPoint 2007.
10. Running the show : Insert the CD in the CD/DVD ROM. It will play automatically. If
it does not play, explore the CD and double click the Main.pps file. Use it as per the
requirement and interest of audience by following the hyperlinks provided on the CD.
This CD will also play on the computer which does not have a PowerPoint Programme.
11. Converting PowerPoint Files into Flash Files : Upload the .ppt file on the website
215
authorstream.com. It will convert and publish your file on the web in .mp4 format. The
website reference may be provided to students for education purpose. They may use
it on any computer connected to internet.
authorSTREAM.com
About authorSTREAM:
What is authorSTREAM?
authorSTREAM is a powerful online presentation sharing engine that not only allows
you to upload your PowerPoint presentations online for free, but also assists you to
share them with your friends, students or co-workers located across the globe.
authorSTREAM is a great online community that gives you access to numerous presentations on varied subjects uploaded by community members. You can find exciting presentations on just about any topic, rate them, post a comment and even embed them in
your blog.
Who all can use authorSTREAM?
authorSTREAM is for everyone :
Educators looking to deliver their presentation to students over the web
Entertainers trying to reach out as many people as they can
Friends and families seeking to keep in touch by sharing their picture slideshows
and greetings
Co-workers and classmates attempting to exchange content such as project presentations, homework assignments etc
What kind of presentation files does authorSTREAM support?
authorSTREAM currently support PowerPoint files (PPT, PPS, PPTX & PPSX format) only.
How can I send feedback for improving authorSTREAM?
Whether you like authorSTREAM, or you have an issue to report or you would like to
see new features and further improvements in it, we would love to hear from you. If you
have any feedback about authorSTREAM, just mail us at feedback@authorSTREAM.com.
Our support executive will get back to you within one business day.
Why cannot I see any slideshow in authorSTREAM player?
You need Flash 8 or above installed on your computer to be able to view an uploaded
presentation.
You may find out some important PowerPoint files uploaded by the author of this
article by feeding index word as "chhabra61" in the authorstream search window. More
than 500 files have been uploaded for use by scientific community and students.
216
Google Translate: can be used to translate text in 65 different languages of the world
as shown below in the window.
Following is the example of translation from English to Hindi.
217
Any person can type in Hindi language as shown below :
If he types agar hamare aas paas koi hai to the google windows show the similarly
pronounced hindi text as : vxj gekjs vkl ikl dks b Z gS rks
PRACTICAL EXERCISE
CREATION OF AN ELECTRONIC MANUAL
1. Create a MASTER FOLDER on the desktop.
2. Name it - Emanual
3. Open MS Word.
a. Type the contents on First page
SLIDE 1
1. About Training
2. Theory Classes
3. Practical Classes
4. Tours
b. Each topic and subtopic of the content should be typed on separate sheet
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SLIDE 2
The training is on computer Education. ………WRITE 4-5 SENTENCES YOURSELF
SLIDE 3……..TOPICS OF THEORY CLASSES
1. Basics of Computer
2. Microsoft Word
3. Microsoft PowerPoint
4. Internet
SLIDE 4……. TOPICS OF PRACTICAL CLASSES
1. Computer Hardware
2. Typing
3. Data Analysis
4. Literature Search
SLIDE 5…….. TOUR PICTURES
1. Agroha Visit
PPT Show
JPG Pictures
2. NBPGR Visit
PPT Show
JPG Pictures
SLIDE 6…….. THANKS
1. Acknowledgement
4. Save Video clips, audio clips, PowerPoint files etc in a folder and save it in the
MASTER FOLDER.
5. Perform Hyper linking
6. Pack and Go
7. Write CD
8. Play on computer
REFERENCES
Web sites consulted :
http://faculty.ncwc.edu/toconnor/425/425syl.htm
http://latin.arizona.edu/~mgen/micgen_98/Lect24/Lect_24.htm
http://www.copscgi.com/fpc/fpcmain.shtml
http://www.sirs.com/search.htm
mailto:Rune.Kornefors@masda.vxu.se
MultiMediaLab, Växjö universitet. Website
http://cebe.cf.ac.uk/learning/habitat/HABITAT3/index.html
http://www.arches.uga.edu/~ninaaug/
http://www.arches.uga.edu/~akrueger/online.htm
http://www.arches.uga.edu/~dibella/TACL/TACLPhase2.htm
219
INTELLECTUAL PROPERTY RIGHTS’ ISSUE IN AGRICULTURE
R. B. Srivastava
Directorate of Human Resource Management
CCS Haryana Agricultural University, Hisar
The recognition of agriculture as a rule-bound enterprise of investment and profit
became obvious with its inclusion in the intergovernmental negotiations for the General
Agreement on Tariffs and Trade (GATT) for the first time in the Uruguay Round (19861994). This round led to the establishment of the World Trade Organization (WTO)
in January 1995. The WTO has a dozen of intergovernmental agreements including
Agreements on Agriculture (AoA), Trade Related Aspects of Intellectual Property Rights
(TRIPs), Sanitary and Phyto-sanitary Measures (SPS), Technical Barriers to Trade (TBT),
Anti-Dumping, Subsidies etc. that directly affect agriculture. In this back ground the
agriculture sector is globally becoming competitive and immerging as knowledge based
industry.
In India also, the agricultural sector is critical to realize further economic growth and
poverty alleviation. The technological support will play crucial role to keep agriculture
as a vibrant and economically attractive occupation. Obviously our national capacity in
frontier areas of science and technology has to be built and strengthened to harvest the
uncommon opportunities available in domestic and global markets. Competition in the
market for varieties of agric-products, is increasingly being driven by innovations.
Recognition to Intellectual Property provides an effective means of protecting and
rewarding innovators which acts as a catalyst in technological and economic development. The institutions, scientists, communities, farmers and individuals need to secure
their intellectual creations using various tools of Intellectual Property Rights (IPR)
like patents, trademarks, copyrights, geographical indications, design registrations,
protection of undisclosed information and protection of plant varieties. Infact, after the
establishment of the international institutional mechanisms, such as, the Convention on
Biological Diversity (CBD) and the WTO, and further, signing of International Treaty on
Plant Genetic Resources for Food and Agriculture (ITPGRFA), the importance and the
scope of IPR in agriculture are well realized and recognized all over the world.
TRIPS Agreement
The WTO's Agreement on Trade-Related Aspects of Intellectual Property Rights
(TRIPS), negotiated in the 1986-94 Uruguay Round, introduced intellectual property protection rules into the multilateral trading system for the first time. Before the WTO's
Uruguay Round, intellectual property laws were a matter for domestic policy. But the
introduction of the TRIPS Agreement made it mandatory for all WTO members to provide
for internationally acceptable and enforceable patent protection for new inventions in
all areas of technology. In turn, this may bring fundamental changes in the way of
traditional agricultural approach which is practiced in developing countries. IPR linked
path way is likely to facilitate the growth of agri-business and industries. The Doha
220
Declaration on WTO clarifies the scope of TRIPS stating that TRIPS can and should be
interpreted in light of the goal "to promote access to technology for all".
Role of TRIPS Agreement :
The ratification of TRIPS is a compulsory requirement of World Trade Organization
membership and any country seeking to obtain easy access to the numerous
international markets opened by the World Trade Organization must enact the strict
intellectual property laws compliant to TRIPS. For this reason, TRIPS is the most important multilateral instrument for the globalization of intellectual property laws. The WTO's
TRIPS Agreement is an attempt to narrow the gaps in the way these rights are protected
around the world, and to bring them under common international rules. It establishes
minimum levels of protection that each government has to give to the intellectual property of fellow WTO members. TRIPS also specify enforcement procedures, remedies,
and dispute resolution procedures. In doing so, it strikes a balance between the long
term benefits and possible short term costs to society. Society benefits in the long term
when intellectual property protection encourages creation, invention and licensing and
also when the period of protection expires and the creations and inventions enter the
public domain.
Major Provisions of TRIPS
Copyright terms must extend to 50 years after the death of the author, although films
and photographs are only required to have fixed 50 and 25 year terms, respectively.
Copyright must be granted automatically, and not based upon any "formality", such
as regisration or systems of renewal.
Computer programs must be regarded as "literary works" under copyright law and
receive the same terms of protection.
National exception to copy right (such as fair use in the United States) must be
tightly constrained.
Patents must be granted in all "fields of technology," although exceptions for certain
public interests are allowed (Art. 27.2 and 27.3) and must be enforceable for at least
20 years (Art 33). Exceptions to patent law must be limited almost as strictly as
those to copyright law.
TRIPS Article 27.3(b) requires countries to grant patent protection to micro-organisms, non biological and microbiological processes. WTO members must also protect plant varieties either through patents or through an effective sui generis system
or a combination of both. Most developing countries have opted for the sui generis
protection of plant varieties taking into account their agricultural development and
farming practices.
In each state, intellectual property laws may not offer any benefits to local citizens
which are not available to citizens of other TRIPs signatories by the principles of
national treatment ((treating one's own nationals and foreigners equally with certain
limited exceptions, Art.3 and 5). TRIPS also has a most favoured nation clause
(equal treatment for nationals of all trading partners in the WTO).
221
The TRIPS Agreement has an additional important principle : intellectual property
protection should contribute to technical innovation and the transfer of technology.
Both producers and users should benefit, and economic and social welfare should
be enhanced.
All the WTO agreements (except for a couple of "plurilateral" agreements) apply to
all WTO members. The members each accepted all the agreements as a single
package with a single signature - making it, in the jargon, a "single undertaking".
One of the fundamental characteristics of the TRIPS Agreement is that it makes
protection of intellectual property rights an integral part of the multilateral trading
system, as embodied in the WTO.
Article 31 of TRIPS allows compulsory licensing and government use of a patent
without the authorization of its owner. But this can only be done under a number of
conditions aimed at protecting the legitimate interests of the right holder.
TRIPS Agreement and the pre-existing international conventions
The TRIPS Agreement is sometimes described as a "minimum standards"
agreement. The obligations of the main conventions of World Intellectual Property
Organization (WIPO) - the Paris Convention on industrial property, and the Berne
Convention on copyright (in their most recent versions) have been incorporated to some
extent. With the exception of the provisions of the Berne Convention on moral rights, all
the substantive provisions of these conventions are incorporated by reference. They therefore become obligations for WTO member countries under the TRIPS Agreement - they
have to apply these main provisions, and apply them to the individuals and companies of
all other WTO members. The TRIPS Agreement also introduces additional obligations in
areas which were not addressed in these conventions, or were thought not to be sufficiently addressed in them. The TRIPS Agreement is therefore sometimes described as a
"Berne and Paris-plus" Agreement. The text of the TRIPS Agreement also makes use of
the provisions of some other international agreements on intellectual property rights.
WTO members are required to protect integrated circuit layout designs in accordance
with the provisions of the Treaty on Intellectual Property in Respect of Integrated
Circuits (IPIC Treaty) together with certain additional obligations. The TRIPS Agreement
refers to a number of provisions of the International Convention for the Protection of
Performers, Producers of Phonograms and Broadcasting Organizations (Rome Convention), without entailing a general requirement to comply with the substantive provisions
of that Convention. Article 2 of the TRIPS Agreement specifies that nothing in Parts I to
IV of the agreement shall derogate from existing obligations that members may have to
each other under the Paris Convention, the Berne Convention, the Rome Convention and
the Treaty on Intellectual Property in respect of integrated circuits.
WIPO's (website: www.wipo) objectives are to promote intellectual property protection throughout the world through cooperation among states and, where appropriate, in
collaboration with any other international organization. WIPO also aims to ensure administrative cooperation among the intellectual property unions created by the Paris and
Berne Conventions and sub-treaties concluded by the members of the Paris Union.
222
Intellectual Property Rights
Intellectual property right (IPR) is a lawful right of an individual granted by government for a specified period on the ownership of the property created through his intellect. It is for effective use of knowledge for economic growth.
Objectives of Granting IPR
i. To enhance the performance levels of institutions and individuals.
ii. To give recognition and financial benefits to the efforts for the creativity
iii. To create competition among the researchers and institutions for quality of research
iv. To have return on investment in research
v. To fasten the technology transfer through licensing and other means
vi. Society benefits in the long term when intellectual property protection encourages
creation, invention and licensing and also when the period of protection expires and
the creations and inventions enter the public domain.
Emerging Importance of IPR
In developed countries the IPR portfolio has now become an effective platform for
benchmarking of intellectual assets and enhancing innovative capabilities of institutions,
business entrepreneurs and researchers. This is being used extensively in today's world
for acquisitions, strategic alliances, licensing arrangements and venture capital funding
in industries. It is important to appreciate the salient features of IPR and integrate them
in institutional working so that one can not only create new and useful inventions that go
into products and processes but also generate appropriate IPR and enforce them,. India
has already started working on bilateral trade agreements keeping in view the IPR issues. Capacity building on IPR issues has become important as the whole trade is
shifting fast keeping IPR as tool of promotion of trade and collaboration.
The legislations covering IPRs in India
Patents : The Patents Act,1970 and was amended in 1999 and 2002. The amended
Act after the amendments made in 2002 came in to force on May 20, 2003.
Design : A new Design Act 2000 has been enacted superseding the earlier Designs
Act 1911.
Trade Mark : A new Trademarks Act, 1999 has been enacted superseding the earlier
Trade and Merchandise Marks Act, 1958. The Act came in force from Sept. 15, 2003.
Copyright: The Copyright Act, 1957 as amended in 1983, 1984 and 1992, 1994,1999
and the Copyright Rules, 1958.
Layout Design of Integrated Circuits: The Semiconductor Integrated Circuit Layout
Design Act 2000. (Enforcement pending)
Protection of Undisclosed Information: No exclusive legislation exists but the matter
would be generally covered under the Contract Act, 1872.
Geographical Indications: The Geographical Indication of Goods (Registration and
Protection) Act 1999.
223
Protection of Plant Varieties and Farmers' Rights Act 2001: Sui generis system of
plant varieties protection.
National Biological Diversity Act 2003: It shall provide legal protection to our biodiversity.
The administration of IPRs in the country
Patents, designs, trademarks and geographical indications are administered by the
Controller General of Patents, Designs and Trademarks which is under the control of the
Department of Industrial Policy and Promotion, Ministry of Commerce and Industry. Copyright is under the charge of the Ministry of Human Resource Development. The Act on
Layout Design of Integrated Circuits is implemented by the Ministry of Communication
and Information Technology. For Protection of Plant Varieties and Farmers Rights, an
Authority called PPV &FR Authority is in place. Similarly National Biodiversity Authority has been established.
The TRIPS agreement says that governments have to ensure that intellectual property rights (IPRs) are enforced under their laws, and that the penalties for infringement
are tough enough to deter further violations. Several legislative and institutional adjustments have been made for Intellectual Property (IP) protection in India to gear up for
quality research and face the challenges of globalization. Copy Right ACT 1957 amended
in 2000, Patent Act 1970 amended in 2004-05, Trademark Act 1999, Design Act 2000,
Geographical Indication Act 1999, Protection of Plant Varieties & Farmers Rights Act
2001, Biological Diversity Act 2002 are some of the very important Intellectual Property
Protection Acts in India. The government has also established modern offices for the
protection of Intellectual properties.
Initiatives taken by CCSHAU
For the effective implementation of IPR management in agriculture, Indian Council of
Agricultural Research (ICAR) has already issued guidelines, which can be followed as
such or adjusted as per state and institutional needs. CCS Haryana Agricultural University has adopted the ICAR Guidelines and formulated its own institutional "IPR Policy
and Regulations" which have been implemented. The whole policy document is place at
university website http://hau.ernet.in This policy envisage incentives to the inventors by
way of royalty & recognition, provision of licensing of technology and encouragement for
inter-institutional and public-private sector linkages. However, it is important to understand how to reap benefits from an organized IPR system. It requires to be aware of
basics of TRIPS and IPR and take care of capacity building on IP management.
Note : The present document has been prepared by collecting information from official websites
of WTO, Technology Information, Forecasting and Assessment Council's, Policy papers
released by National Academy of Agricultural sciences & Indian Patent office of India .
224
HISTORY OF INTRODUCTION OF EUROPEAN/ WESTERN
HONEY BEE (APIS MELLIFERA LINNAEUS) INTO INDIA
N. P. Goyal* and Pardeep K. Chhuneja**
Department of Entomology,
Punjab Agricultural University, Ludhiana 141 004, Punjab
On date, eleven Apis species have been reported to exist in the world besides Apis
oligocenia and Apis armbursteri as the fossil honey bee species. Among the 11, whose
nests consist of multiple combs include Apis cerana, Apis nuluensis, Apis koschevnikovi,
Apis mellifera and Apis nigrocincta. The species whose nests are single combs include
Apis dorsata, Apis laboriosa, Apis binghami, Apis breviligula, Apis florea and Apis
andreniformis . India was known to be home for A. dorsata and A. florea, the wild bees
and A. cerana , the hive bee. A. laboriosa , another wild honey bee was newly found
species in India from Sikkim. The various problems in the beekeeping with A. cerana ,
the only earlier hive honey bee species in India, such as its unsuitability to take up for
successful beekeeping venture in the larger part of our country which is plain and has
high temperature conditions particularly during summer months and, thus, low productive in such areas, its high absconding and swarming tendencies, its more prone to wax
moth attack it being little propolizer, low foraging range and lower tolerance in terms of
its non-withstanding maneuverability for breeding and apicultural diversification and not
thriving well in hot plains, and hence, not suited for commercial apiculture were always
in the minds of Indian beekeeping experts which triggered their efforts to introduce
Western/European honey bee, A. mellifera into India which was known to be free from
above problems.
The first attempt to introduce A. mellifera into India dates back to late eighties of
nineteenth century (1882) by John Douglas in Bengal (Douglas, 1984), the fate of the
same however, is unknown. His intentions had been to multiply the colonies and
distribute among the farmers. Following lone effort, the renewed efforts started in early
twentieth century by C.C. Ghosh. Ghosh in 1920 by imported the bee colonies from Italy
and Australia through ships but failure of queen bees mating resulted in ultimate finish of
apiary maintained till 1931 (Ghosh, 1920, 1939). Then, Hatch in 1928 imported six
colonies from Italy and kept these at Trivandrum, but the fate of this apiary remains a
mystery. Subsequently, Baldry in Mahabaleshwar (M.S.) maintained introduced 30 A.
mellifera colonies for six years which were later shifted to Coimbatore where these
dwindled and perished. Beadnell (1939) then brought some consignments of Caucasian
race of A. mellifera and maintained the apiary in Nilgiri hills, but no information is
available on its subsequent fate. Thompson in1940 made introductions in Kerala but
these colonies too could not be established. In north India, the first efforts were, however, made much later. Rehman and Singh (1940, 1945, 1946) made some unsuccessful
attempts - two consignments each of two and three colonies were imported. The first
consignment of two colonies was received in April 1938 and introduced at Katrain (H.P.)
but they perished in summer. Then again three colonies were imported by RAF plane;
225
two colonies died on the way and the third kept at Nagrota-Bagwan made a good start
but could not overwinter. A. mellifera colonies were later again imported from Italy into
Kashmir in 1951 (Vats, 1953) and the colonies reportedly continued till 1959, however,
there were no subsequent reports, and so presumed to have been perished. All such
cases of introduction did not make any success further because these introductions
were made in a very unorganized manner and, therefore, none of these importations
could make any significant success/impact. Such a work has been reviewed by several
workers (Atwal, 2000).
After earlier failures, the mission was then taken-up by Punjab Agricultural
University (PAU) which imported eight consignments of A. mellifera from USA, Italy and
England between 1962-1964 into Nagrota-Bagwan and Kullu, the erstwhile Punjab (now
in H.P.). The project on the introduction of A. mellifera was taken up by the PAU in a very
well organized manner by a team of devoted/founder bee scientists (Dr. A. S. Atwal, O.
P. Sharma and N. P. Goyal) with Dr. A. S. Atwal, Head of the Dept. of Entomology,
Punjab Agricultural University, Ludhiana, as the leader of this team. For the ultimate/
final success of this project, vital contributions were also made by successive bee
scientists and even other Agricultural scientists/persons of other organizations/ other
departments of the PAU too. Therefore, the combined and organized efforts/contributions of all such persons that made very strong links of the continuous long chain, were
the real crux that made the .honey bee, A. mellifera get introduced and firmly
established successfully, not only at the bee research farms of PAU/ Punjab state but in
the country as a whole.
To begin with, research work on this project was started in the hills at NagrotaBagwan/ Kullu (now in Himachal Pradesh), but later on in 1966, experimental work of A.
mellifera introduction was also taken up in plains of Punjab in Ludhiana.
As such from 1962 to 1971, a total of 12 importations were made mostly (8) from
USA, two from Australia and one each from England and Italy. Further, the queens were
imported nine times while the package bees were imported three times (total 68
packages).Out of the total (238 queens), 18 queens were imported before the arrival of
package bees while the rest (220) at the time or after the importation of package bees.
As may be seen in the Table 1, the first three attempts met the same fate as
experienced by the earlier workers (before 1962). However, out of the four queens
imported in June 1963 (fourth attempt), only two queens survived. As such, in the subsequent years, the importations were made in the form of both package bees and queens,
of different stains. Eventually, the Californian stain was found to be more suitable to the
agro climatic conditions prevailing at Nagrota and Ludhiana and the same stain was
multiplied further. The earlier difficulty at Ludhiana for getting locally raised virgin queens
mated was solved by adopting suitable management and synchronizing the virgin queen
emergence with that of large population of mature drones.
All these efforts resulted in the increase of the number of foreign bee colonies all
most at equal rate, at both the stations ie.160 at Nagrota & 140 at Ludhiana by the year
226
1973-74. Similar observations were recorded by Dr. Sardar Singh, who visited the
University on the request of PAU, for the review and assessment of the project on May
20-31, 1974.
THE PRESENT STATUS
Impact of the A. mellifera introduction into India and present status
The impact on the status of development of beekeeping owing to the introduction and
establishment of A. mellifera in India is obvious from the fact that at present, there are
8.17 lakh A. mellifera colonies working on the farmers fields for pollination services of
crops, providing livelihood for a huge number of landless beekeepers, generating income
for the traders and technicians beautifying the nature and enjoyment for the general
public, and above all a noticeable pride for the Nation to have become one of the leading
honey producing country in the world and also by providing the additional revenue for the
national exchequer by way of increasing productivity of crops through cross-pollination.
Moreover, these colonies of Italian honey bee at present are producing as much as
305,500 quintals of honey with an average of 37.42 kg/colony/year and thus have not
only contributed in a considerable manner for the improvement of the nutrition of the
citizens of India, but has also helped the nation to earn a lot of foreign exchange through
the export of this honey to other countries. The state wise distribution of these Italian
honey bee colonies is that so far Punjab is the only single state having the largest
number of 350,000 colonies, followed by Haryana having 105,500 colonies, Himachal
Pradesh 50,000 colonies and J&K with 15,000 colonies. Bihar and Jharkhand together
have 200,000 colonies, while the other states including UP, AP, Kerala, Karnataka,
Rajasthan, MP, Chhattisgarh and Orissa maintain a total of 19,000 colonies of imported
species of honey bees. The number of colonies is being multiplied by the beekeepers at
a tremendous rate and, therefore, more and more colonies of these exotic bees are
being added every year for serving the nation with a still added vigor and on a larger
scale. The impact of all such efforts made by the devoted workers on the development of
beekeeping in general and for the development of beekeeping with the help of imported
honey bees A. mellifera can further be realized by there comparison with the similar
figures published by Dr. Goyal in the year 1993 at the time of First National Conference
on Beekeeping held at Chandigarh, June 1993. It is, therefore, a matter of great pleasure
that there is a huge difference in figures then and now i.e. after gap of 19 years. The
increase the number of colonies of A. mellifera has been 716.50% while it is only 109.74%
in case of A. cerana . Similarly, the increase in honey production has been 1937.96%
and that in A. cerana 129.44%. The increase in average production of honey per year per
colony has taken place to the tune of 270.57% while that in Indian honey bees, it is
118.14%. All these present data on the number of colonies, total honey production and
increase in average yield of honey production per colony is bound to convince every and
anyone of the magical impact of A. mellifera introduction and establishment in India on
the over all development of beekeeping in this country. Further, India could present a
unique and rare feat of running exclusively a 'honey train' carrying 90 boggies with a total
of 2,000 tonnes of honey from Ludhiana to Mumbai on April 16, 2009 for its export and
227
then again on April 15, 2011, two trains carrying 4,000 tonnes of honey. The commercialization and industrialization in beekeeping which we visualize now and also in bringing
'Sweet Revolution' in the country owes exclusively to the introduction of A. mellifera into
India by the PAU which has brought cheers on the faces of the farmers and has resulted
in employment opportunities for unemployed youth. It is pertinent to add that the
country could achieve Green Revolution towards bringing about self sufficiency in grain
production through introduced dwarf wheat germplasm, the same has turned true in beekeeping in India as all states and national level apicultural fora revolve around promotion
of high honey yielder A. mellifera for rural upliftment though both fast paced augmentation of hive as well as crop productivity.
THE FUTURE OF A. MELLIFERA IN INDIA
Apis mellifera introduction? (STOP) and establishment in India (a required action in
future).
As is evident from the heading above, a big question mark after the word introduction
means as to what and why is the need of 'introduction' of fresh stock of the Italian or
others strains of A. mellifera from abroad in future particularly because now we already
have lakhs of exotic honey bee colonies capable of very high potential of honey production and cross-pollination of crops. Further, the importation of new stock in future will
instead of doing any good, may involve a great risk of importation of not only new bee
diseases but also the Dangerous Killer Bee (Africanized honey bee) and American
foulbrood which are so far not present in our country. Moreover, scientifically it is
not possible to judge the quality (good or bad) of a queen bee simply by seeing it or
examining it physically. Besides this, it is also not sure or necessary that if any queen
has performed in the best way in its country of origin, the same will also perform best in
any other country situations or agro-climatic conditions. Added to it, the performance of
the progeny produced from the queen also depends upon the strain of drone with which
she had mated.
Because of the above draw backs involved in the future importations of exotic honey
bees/queens and keeping in a view such danger and risks involved, the word STOP has
been put after the question mark. Moreover, the word stop has been written in capital,
larger and bold letters which means that further importations have to be permanently
stopped and under no circumstance, it should be permitted by the Govt. or any other
agency concerned with such importations.
In spite of all the facts given above, some persons still want to import more queens
from abroad. The question is why they want to import more queens from outside. The
answer is that either out of greed i.e. they want to import queens in a very large number
under the pretext of very high quality queens and sell them here to the gullible public at
exorbitant rates and mint huge money or some of them may want to gain prominence
simply by doing something new. Such persons may be high profile people but having
poor or shallow knowledge of bees and beekeeping. Whatever may be the cause of their
supporting the new importations from the abroad, we must remain careful and be clear to
228
put a permanent end of further new importations of A. mellifera in any form.
CONCLUSION
The performance of A. mellifera stock so far imported has been found to be excellent
both for honey production and pollination of crops. These are the time tested observations for the past more than four decades. Therefore, for further multiplication and distribution, we should use only the already available stock of the exotic bee. New importations in any form must be stopped forth permanently. For taking any further crucial
decision regarding honey bees and beekeeping, bee scientists having both theoretical
as well as practical insight of working with honey bees must be associated so that any
undesirable happening or move may be snubbed at its very beginning.
Suggested Readings
Goyal, N. P. 2011. The past, present and future of Apis mellifera introduction into India
with special reference to the initiative taken and efforts made by the Punjab
Agricultural University, Ludhiana, pp. 1-17. In : Chhuneja, P. K.; J. Singh,
B. Singh and S. Yadav (eds), Prospects and Promotion of Apiculture for
Augmenting Hive and Crop Productivity . Department of Entomology, Punjab
Agricultural University, Ludhiana, 247 pp.
229
BIOSYSTEMATICS OF INSECT POLLINATORS : A BASIC NEED
Sucheta Khokhar
Dean, College of Agriculture,
CCS Haryana Agricultural University, Hisar
India has only 2.4% of total global land with population of 121 crores according to
recent census and main occupation of people is still agriculture. For any nation's progress
and prosperity five factors are most important i.e. land, water, environment, forest and
biodiversity. Our country may not be rich in having the first four factors but with reference to biodiversity it ranks at position eighth to be recognized as 'Hot Spot for
Biodiversity'. We need to conserve, promote and propagate biodiversity of flora and
fauna. The flora especially terrestrial plants are mainly either cross-pollinated or selfpollinated to produce seeds or fruits. Different groups of insects have been recognised
as effective pollinators. Insect pollination is also known as Entomophily.
Insects are most dominant and diverse group of animals on the earth, which
appeared 250 million years ago. Insects are presumed to constitute about three-fourth
of all living animals on earth. They fill many niches in both terrestrial and aquatic ecosystems; and a good number of them are celebrated pests of agricultural, medical and
veterinary importance. Existing knowledge on insect biodiversity is poor and no one
knows exactly how many species of insects exist. Widely divergent estimates have
been provided including up to 30 million species (Erwin, 1982), 12.5 million (Hammond,
1992) and 5-15 million (Stork, 1997) and 1-1.5 million named and described species and
countless species yet to be discovered (most of text books). According to Slater (1984),
it is there that most of the species of the world occur, only some thousand insect species new to science are added and described very year which constitute only a very
small proportion.
Still many species are to be recorded / discovered. But many established species
are either already become extinct or at the verge of extinction or qualified as endangered
(Table 1) as per IUCN (International Union for Conservation of Nature) and more information can be collected from the Red list page - http://www.iucnredlist.org/ so that they
can be protected.
Table 1.
International Union for Conservation of Nature (IUCN)
STATUS
CATEGORIES
Extinct
Species not definitely located in the wild during the past 50 years.
Endangered
Taxa in danger of extinction and whose survival is unlikely if the causal
factors continue operating.
Vulnerable
Taxa believed likely to move into the Endangered category in the near future if
the causal factors continue operating.
Rare
Taxa with small world populations that are not at present 'Endangered' or
'Vulnerable', but are at risk.
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Recently, a broader term 'Biosystematics' is more in use instead of Taxonomy/Systematics which may be defined as, 'Biosystematics is the science through which life
forms are discovered, identified, described, named, classified and catalogued, with their
diversity, life histories, living habits, roles in an ecosystem, and spatial and geographical distributions recorded. According to Danks (1988) knowledge of these species and
their relationships are needed to summarize information, to predict other findings, and
to understand processes.
Biological systematics is the study of the diversification of life on the planet Earth,
both past and present, and the relationships among living things through time. The main
function of biosystematics is to generate the fundamental knowledge of all the living
things on which other fields of biological research and applied programs depend, as
expressed in surrounding circles (Fig 1).
Fig 1. Role of Biosystematics
The contributions of biosystematics to biology are both direct and indirect and has
aided substantially the biological arts which are the fields known as the applied sciences including economic entomology, parasitology, biological control, conservation,
veterinary medicine as well as public health. In some cases total dependence on biosystematics is not ruled out. To know specifically the areas both in theoretical and
applied biology, the scientists are benefited by biosystematics. The field of biological
systematics is broad one, and within it is brought together at least a part of all natural
science disciplines. It represents the orderly understanding and sum total of our knowledge of the animal and plant kingdoms.
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Importance of Biosystematics
Biosystematics plays a central role in biology by providing the means for characterizing the organisms that we study. Through the production of classifications that reflect
evolutionary relationships it also allows predictions and testable hypotheses. By allowing taxa (taxonomic groups) to be correctly identified classifications provide a key to the
literature and a means for organizing information (Danks 1988). Our ability to predict
biological characteristics is a particularly valuable product of classifications that often
is taken for granted. The importance of sound biosystematics with respect to pollinators
is obvious. Pollinating insect species must be correctly identified so that efforts for
their augmentation and conservation could be successful. Armed with identification we
automatically know something about the biology and distribution of an organism. If the
species has previously been studied, the literature can be tapped for information. If it
has not been studied, some preliminary measures can be taken based on knowledge
accumulated on related species.
Characters and Their Use in Biosystematics
Taxonomic characters have been variously defined, but for our purpose we can
consider them as attributes of a taxon that allow its differentiation or potential differentiation from others. Characters or traits used in taxonomy are hypothesized as being
under genetic control although this is rarely tested directly. Characters are used to
construct classifications and to identify the taxa which classifications recognize. A character useful for identification is not necessarily useful for constructing a classification,
and vice-versa. Taxonomic characters can be conveniently categorized as morphological, physiological, molecular, ecological, reproductive and behavioral. For our purposes
"biological characters" will specifically refer to the last three categories. Reproductive
characters are herein restricted to mode of reproduction and reproductive compatibility.
The vast majority of classifications and keys for identification are based on morphological characters. This is not because they are inherently better for systematics but
because they are more easily observed and evaluated for variation. The other kinds of
characters often require expensive equipment, live material and they are more difficult to
voucher. Estimating variation in particular is not a trivial matter with non-morphological
characters. Given reasonably complete collections in museums, it is relatively straightforward to determine if a morphological character occurs throughout the range of a
species, in all or only a subset of the known species of a genus, in all or only a subset
of the known genera in a family, etc. The equivalent documentation for consistency of
biological characters such as host preference, or reproductive incompatibility requires
far more energy and resources. Consequently the danger of basing taxonomic hypotheses on insufficient data generally is greater when non-morphological characters are
emphasized. This is not to discourage the use of non-traditional character sources in
systematics, indeed they are often indispensable, but simply to stress the importance
of adequate sampling. Certainly, classifications and species concepts are most robust
when based on and supported by a variety of character sources.
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For easy identification of insects to different levels of classification, various types of
keys are available in the literature which are based mainly on morphological characters.
A key is a systematic framework for zoological classification (generally used for identification to the exclusion of other purposes) with a sequence of classes at each level of
which more restricted classes are formed by overlap of two or more classes at the next
higher level. A key involves no principle of priority and has a purely arbitrary conventional
sequence keys are universally considered artificial. There are many types of Keys, viz.,
Indented keys, Tabulated keys, Dichotomous- bracket keys/ simple non- bracket key,
Pictorial keys, Circular keys, Box-type keys. Most of taxonomic literature or text books
refer to dichotomous/analytical keys. The characters of an organism are expressed in
couplets which are numbered 1 and 1' 2 and 2' and so on. Thus, each step leads to
another step and it alternatives, until a name is reached. One's success in running an
insect through a key depends largely on an understanding of the characters used.
The keys, which have been constructed in majority of the text books or other sources
for the identification of important insects as pollinators belonging to the following different orders, generally include diagnostic characters e.g.:
1.
Hemiptera : Habitat (aquatic, semiaquatic or terrestrial); head constricted behind
eyes or not constricted; antennae 4-or 5-segmented, antennal length (as long as or
longer/shorter than head), antennae exposed or concealed in cavities, ocelli present
(paired) or absent; labium 1 to 4- segmented; membrane of hemelytra (distinct or
indistinct), when distinct, with five/less veins or many veins; corium entire or divided
into cuneus and/or embolium, fore legs (simple or raptorial); tibiae (spinose or not);
tarsi 2- or 3- segmented; scutellum small or large; connexivia of abdominal tergites
(upto 6 or 7 segments) visible.
2. Lepidoptera : Mandibles (functional or non-functional);lacinia of adults (well developed or not), galeae (haustellate or not); antennae variously modified (clavate, setaceous, pectinate, bipectinate, filiform etc.); wing-coupling apparatus (present or absent), wings (broad with well-developed venation or wings narrow or cleft into plumes
with or without venation or reduced venation); tympanal organ (present or absent),
when present may be in metathorax or abdomen; tibial spurs (present or absent);
female (with 1 or 2 genital openings).
3. Diptera : Ocelli(3) present, may be absent or indistinct; antennae (short or elongated), variously modified (aristate, setaceous, plumose, pilose, stylate
etc.);mandibles either absent or modified as stylets in adults; thorax with or without
v-shaped suture on mesonotum; wing venation of fore wings (variable).
4. Hymenoptera : Abdominal attachment with thorax (broad or constricted); antennae
insertion (below eyes and below apparent clypeus or between eyes, well above the
clypeus); flageller length (very long or not abnormally long); hind margin of pronotum
(almost straight or deeply emerginate behind); wings (well developed or absent or
may be very rudimentary), wings when present with distinct venation and closed
cells, fore wings (with or without distinct pterosigma); hind femur (with or without
trochantellus).
233
5. Coleoptera : Habitat (terrestrial or aquatic); clypeus extending or not, laterally in
front of antennal insertions; eyes not divided or completely divided into dorsal and
ventral parts; antennae variously modified (filiform, moniliform, setaceous, pectinate,
serrate, lamellate etc.); metasternum (with or without groove); shape of fore coxae
(conical or spherical), hind coxae (immovably fixed or not immovable fixed to metasternum, dividing or not dividing the first visible abdominal sternite).
Identifying Pollinators One study speculated that it might be "some kind of scent or
marking" that attracts a butterfly. Another study found that many butterflies produce
pheromones to entice the opposite sex, and this scent is similar to flowers that they are
drawn to.
Important pollinators with their significant role in pollination belong to orders
Hymenoptera, Diptera, Coleoptera, Lepidoptera and Hemiptera. Some of the plants have
specific requirements of a particular pollinator and such plants can not survive in the
absence of such pollinators. Similarly, some of the pollinators have specific plant hosts
without which their survival is endangered.
Primary pollinators are honey bees, bumble bees, sweat bees, mining bees, wasps,
butterflies, moths, beetles, dipterous flies and some true bugs. Imported European honey
bees also play a critical role in pollinating crops.
Bees, bumblebees, flower flies, a few types of stink bugs, leafhoppers and several
other types of insects are also found visiting flowers attracted by their nutritious pollen
and nectar. But most of them arrive at the flowers too late, after the flowers are past their
prime and are not receptive for pollination. So it is the beetles that carry the lion share
of the responsibility for perpetuating these plants.
LEPODOPTERA
Butterflies
Butterflies are found on every continent but Antarctica; the U. S. is home to about
700 different species. Their beauty and mystery have enchanted mankind for centuries
and are woven into folklore and legend. In ancient Hopi, Mayan and Aztec cultures, the
butterfly was one of the most frequently represented figures.
Butterflies are very active during the day and visit a variety of wildflowers. Butterflies
are less efficient than bees at moving pollen between plants. Highly perched on their
long thin legs, they do not pick up much pollen on their bodies and lack specialized
structures for collecting it. Butterflies probe for nectar, their flight fuel, and typically
favor the flat, clustered flowers that provide a landing pad and abundant rewards. Butterflies have good vision but a weak sense of smell. Unlike bees, butterflies can see red
Butterflies often feed during the day, and most moths feed at night, though there are
exceptions. utterflies must land on flowers to feed, while many moths are able to flutter
before a flower while feeding. This affects the types of flowers that these insects prefer:
butterflies need a large landing platform, so they prefer large, flat flowers, while moths
can be attracted to cup-shaped flowers.
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Butterfly
Butterfly
Lepidopterous Pollinators
Moth
Butterflies are very active during the day and visit a variety of wildflowers. Butterflies
are less efficient than bees at moving pollen between plants. Highly perched on their
long thin legs, they do not pick up much pollen on their bodies and lack specialized
structures for collecting it. Butterflies probe for nectar, their flight fuel, and typically
favor the flat, clustered flowers that provide a landing pad and abundant rewards. Butterflies have good vision but a weak sense of smell. Unlike bees, butterflies can see red.
One study speculated that it might be "some kind of scent or marking" that attracts a
butterfly. Another study found that many butterflies produce pheromones to entice the
opposite sex, and this scent is similar to flowers that they are drawn to.
As butterflies are perching feeders, they favor flowers with a landing platform (labellum). They gather pollen as they walk around flower clusters on their long and thin legs.
Researchers concluded that butterflies prefer flower nectar containing considerable
amounts of amino acids. Recently, researchers, from the University of Basel in Switzerland, extended this theory by feeding butterflies nectar with, and without, amino acids.
It makes butterflies sound like the blondes of pollinators. Though butterflies may not be
premiere pollinators, their continual flitting from flower to flower more than makes up for
the quantity of pollen they carry. Another reason butterflies have not been taken seriously as pollinators is because they are not considered major players in commercial
food crops. Butterflies laid more eggs when fed nectar containing amino acids. Oddly
enough, butterflies taste with their feet, which is where their taste sensors are located
and by standing on their food, they can taste it to see if their caterpillars are able to eat
it.
Butterflies have smooth, slender bodies, knobbed antennae, rest with their wings
held upright, and fly during warm weather. Their bright coloring is the result of loose,
powdery scales on the wings. Probably the best known of the species in the U. S. is the
orange and black patterned monarch butterfly; however, butterflies come in a wide range
of colors and patterns to delight the eye of the beholder. Butterflies probe blossoms with
their long tongues. Each flower has a nectary usually hidden in narrow tubes or spurs
that is suitable in length. This tongue or proboscis works like a straw, drawing up nectar
and when not in use, the proboscis stays coiled. Butterfly populations are on the decline
due to humans reducing numbers of pollinators by destroying habitats and migratory
nectar corridors, emitting pollution and the misuse of pesticides.
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Moth
After dark, moths take over the night shift for pollination. Nocturnal flowers with
pale or white flowers heavy with fragrance and copious dilute nectar, attract these pollinating insects. Not all moth pollinators are nocturnal; some moths are also active by
day. Some moths hover above the flowers they visit while others land. Hawkmoths are
impressive flyers and some have proboscis longer than their bodies. These giant moths
fly upwind, tracking the airborne fragrance trail to a clump of flowers. Their caterpillars,
tobacco and tomato hornworms, are well known to gardeners as voracious feeders. If
you want to see their colorful adults, sequester these offspring on a few plants in the
corner of your garden. Some moth species, however, are exceptional pollinators. Especially well known are the "hummingbird moths" of the Family Sphingidae. Among the
more important moth pollinators are the hawk moths (Sphingidae). Their behaviour is
similar to hummingbirds: they hover in front of flowers with rapid wingbeats. Most are
nocturnal or crepuscular. So moth-pollinated flowers tend to be white, night-opening,
large and showy with tubular corollas and a strong, sweet scent produced in the evening,
night or early morning. A lot of nectar is produced to fuel the high metabolic rates needed
to power their flight.
Day-flying sphinx moth nectaring
Other moths (Noctuids, Geometrids, Pyralids, for example) fly slowly and settle on
the flower. They do not require as much nectar as the fast-flying hawk moths, and the
flowers tend to be small (though they may be aggregated in heads).
COLEOPTERA
Beetles
Beetles comprise the largest set of pollinating animals, due to sheer numbers. They
are responsible for pollinating 88% of the 240,000 flowering plants globally.
Many beetles visit flowers to prey on other insects, feed on the nectar and pollen, or
on other parts of the plant. Consequently pollen often sticks to them and is inadvertently
transferred between flowers. Beetle-pollinated flowers are usually large, greenish or offwhite in color and heavily scented. Scents may be spicy, fruity, or similar to decaying
organic material. Most beetle-pollinated flowers are flattened or dish shaped, with pollen
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Coleopteran Pollinators
easily accessible, although they may include traps to keep the beetle longer. The plant's
ovaries are usually well protected from the biting mouthparts of their pollinators. Beetles
may be particularly important in some parts of the world such as semi-arid areas.
The pollinating responsibility of beetles has been observed in of these insects that visit
flowers: sap e.g. feeding beetles, tumbling flower beetles, leaf beetles and weevils,
belonging to the families Nitidulidae, Mordellidae, Chrysomelidae and Curculionidae,
respectively.
Beetles were among the first insect to visit flowers and they remain essential pollinators today. They are especially important pollinators for ancient species such as magnolias and spicebush. Beetles will eat their way through petals and other floral parts.
They even defecate within flowers, earning them the nickname "mess and soil" pollinators. Research has shown that beetles are capable of color-vision. Though the majority
of beetles are not floral visitors. Beetles with smooth bodies are not effective pollinators,
but those with hairy bodies can carry pollen between flowers. Beetles visit flowers for
many reasons. Some are truly interested in pollen and nectar as a food source, as are
the other major pollinating insects, but some prefer to eat the flowers themselves, or
other insects. Predatory beetles often hide within flowers, waiting for soft-bodied flies to
visit. Some, such as ladybeetles, visit flowers to feed on small pests such as aphids,
though they may also consume some nectar as a kind of "fast food". Beetles are generally clumsy and rough, compared to the more delicate butterflies and aerodynamic flies.
Beetles tend to visit large, heavily-constructed flowers that are either flat or bowl-shaped
to give them an easy place to land. Relatively large beetles can often damage flowers, or
the pollinating parts of flowers, especially when they feed on pollen with their large
cutting mouth parts. However, many flowers resist this damage either by producing many
more flowers than necessary, or by enclosing their reproductive organs deep within their
corollas.
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HYMENOPTERA
Honey Bees
European honey bee, with black and brownish stripes, living with thousands of
others in a hive full of honeycomb. They range in length from less than one eighth of an
inch to more than one inch; vary in color from dark brown or black to metallic green and
blue; and may have stripes of red, white, orange, or yellow.
Bumble bees
Bumble bees are excellent pollinators, especially of berry species. While bumble
bees are generalist foragers that visit a diversity of flowers, a few groups of flowers, such
as willows and lupines, are particularly important to them. Bumble bees practice what is
called 'buzz pollination' where they grab onto the anthers, the pollen-bearing structure,
of certain flowers and buzz their flight muscles to release the pollen. This behavior is
especially important in pollinating blueberries, cranberries, and tomatoes.
Bumble bees are social insects that build their nests in the ground, often in abandoned mouse burrows, empty bird nests, and under fallen grass. The mated queen overwinters in the soil while the rest of the colony dies at the onset of cold weather. In early
spring, she establishes a new nest and rears the first worker brood. These workers are
small, sterile females that enlarge the nest, forage.
Bumble bees are social insects that build their nests in the ground, often in abandoned mouse burrows, empty bird nests, and under fallen grass. The mated queen overwinters in the soil while the rest of the colony dies at the onset of cold weather. In early
spring, she establishes a new nest and rears the first worker brood. These workers are
small, sterile females that enlarge the nest, forage, and tend to the next generation of
workers. These are larger bees, due to changed nest conditions, such as increased
temperature, cell size, and food availability. Produced in late summer are the fertile
females (next year's queens) and males (called drones), whose sole function is to
fertilize the queens before dying in the fall.
Sweat Bees
Sweat bee is the common name for bees in the Halictidae family, and they are
named for their attraction to the salts in human perspiration. Most sweat bees are small
to medium in size, 1/8 to 3/8 of an inch long. They are generally black or metallic, and
some are brilliant green or brassy yellow. Sweat bees are among the most common
bees. Halictids have a range of nesting habits, from dispersed solitary nests, to densely
238
Bumble bee
Sweet bee
situated ones with individual bees sharing common entrance ways, to primitive social
arrangements. Halictid bees are common insects and good general pollinators.
Andrenid bees
Andrenid bees commonly called mining or digger bees, are another common
pollinator. They resemble the typical honey bee in shape and size. Their bodies are
dark in color and covered with fine, light brown or yellow hairs. Andrenid bees have
chewing-lapping mouthparts used to manipulate and collect nectar and pollen.
The protruding, 'lapping' mouthpart is shorter in mining bees than honeybees, giving
them the common name of short-tongued bees. As their name suggests, mining bees
dig single nests in the soil. Mining bees are solitary and do not form large, socially
organized nests. However, thousands of individuals may nest in a general area with good
nesting habitat.
Wasps
Like bees, yellowjackets and hornets belong to the insect order Hymenoptera. These
species are beneficial to humans for pest control and some pollination. In addition,
thousands of small wasp species are parasites of other insect pests, particularly aphids
and caterpillars. Without parasitic wasps, pests would overtake most crops.
Yellowjackets can be both beneficial and problematic wasps. They are important
predators and scavengers, helping to control pests and recycle organic materials, but
can also be a threat to humans due to their ability to sting repeatedly in defense of their
nests. Yellowjackets are relatively short and stout, holding their legs close to their body
compared with other wasps. Paper wasps, for example, are more slender and have long,
dangling legs. All yellowjackets are striped either black and white or black and yellow.
They are rapid fliers, and are more aggressive than other types of wasps. Their nests are
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Yellowjackets
wasps
Rotundicollis wasp
always enclosed with a papery envelope and can be found in the ground, hanging from
eaves or tree branches, and occasionally in wall voids. The Bald or White Faced 'Hornet,'is
scientifically not considered tobe a hornet, but a large wasp. Its coloration is black and
white. Their nests are found in trees or shrubs and they become very large by summer's
end. The size of the nest, number of individuals in a colony, and the active time beyond
summer all depend on the species.
DIPTERA
Drone Flies
European drone flies ( Eristalis tenax) are actually in the same family as hoverflies
(Syrphidae), but we would like you to count them separately because they are a particularly ubiquitous on some types of flowers and easily recognised once you become familiar with them.
Drone flies are honey bee mimics, but are distinguished by their larger eyes and
their habit of moving their abdomens up and down in a distinctive bobbing motion when
resting on flowers. They also have a more darting flight than honey bees, and generally
appear less "busy" when working flowers. The pattern on the abdomen is also very consistent, although it varies in intensity. Drone flies seem particularly attracted to daisylike flowers with a strong yellow component.
Hover Flies/Syrphid Flies
Hover flies are an extremely variable family (Syrphidae) of flies that range from the
large, bulky and hairy to the small, slender, and shiny. Common features of the family
are large eyes (often wider than the front of the thorax) and a distinctive wing venation in
which veins run parallel to the hind edge of the wing giving the appearance of a false
margin. Although this venation is recognisable in pinned specimens, it will be very difficult or impossible to pick up while doing flower observations. There are two basic forms
of hover flies: the small-bodied types from which the common name is derived, and the
large-bodied varieties that rarely hover.
The small bodied ones tend to be quite recognisable. These are the ones that have a
distinctive hovering flight, in which they appear to hang still in the air (like a tiny
hummingbird), and then dart off rapidly to a new location or settle on a flower. They often
have banded abdomens and may have a black or metallic thorax.
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The large-bodied varieties include some of the bee mimics like the drone fly (which
are discussed separately above), and the narcissus bulb fly, which is a bumble bee
mimic. Other large-bodied hover flies include the native Helophilus varieties which have
a series of pale yellow and black stripes running lengthwise down the thorax and a
variable number of yellow or orange patches on the sides of the abdomen. There is also
a metallic blue variety that is likely to be confused with a blue-bottle blow fly. Don't be
too concerned if you can't figure out the various large-bodied hover flies, as they will still
be picked up in the basic "big flies" category and will hopefully be represented in your
voucher collection.
Crane Flies
Crane flies (also called daddy longlegs) belong to family (Tipulidae) are a very
recognisable group on account of their overly long, fragile legs. With over 550 NZ
species, there is enormous variety, with some measuring just a few millimetres and
others over 15 cm across the legs. Crane flies belong to the thin-bodied group of flies so
should generally be classified as "small flies". Most crane fly activity on flowers occurs
at dusk and the early hours of darkness. Some crane flies, such as the aptly named
Elephantomyia , have greatly elongated mouthparts that are presumed to be adapted for
taking nectar from tubular flowers.
Bulb fly
Tabanid fly
Tachinid fly
Gad fly
Hover fly
Syrphid fly
Tabanid fly
Gad fly
Syrphid fly
Dipterous Pollinators
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Gad Flies
Gad flies (also called horse flies) generally resemble large, somewhat flattened, bigeyed blow flies belong to family Tabanidae. With their long wings held out at a slight
angle from their body they have a somewhat deltoid shape and have been described as
resembling "stealth bombers". Another key feature is the elongate beak-like mouthparts
(some overseas species feed on blood and can give very painful bites). They also have a
distinctive wing venation in which two apical veins are splayed out either side of the wing
tip. There are about 20 species in New Zealand, usually in shades of black, grey and
brown.
When busy foraging for nectar, gad flies walk slowly between flowers and tend to
allow you to observe them very closely. Blow flies, on the other hand, have a tendency to
move rapidly between flowers and are easily scared to flight.
Blow flies and Bristle flies
The blow flies and bristle flies belong to families Calliphoridae and Tachinidae, respectively. These are the "calyptrate" flies. They tend to be fast-flying, fat-bodied species that are often tricky to get close to in a field situation. Blow flies or bluebottles are
well known for breeding in decaying organic material such as carrion, whereas the bristle
flies are obligate parasites. Some of the bristle flies are distinctive, and others, however, are very similar to bluebottles or muscids. For simplicity sake, it is easier to treat
flies you see of this type simply as "big flies".
The insect species belonging to different orders as visitors/ pollinators have been
recorded under agroclimatic condions of Haryana State and expressed in the following
Tables 2-5.
Table 2.
Coleopterous insects as flower visitors/pollinators of different plants
under agro-climatic condition of Haryana
S. No. Scientific name
Family
Order
1.
Coccinella septumpunctata L.
Coccinellidae
Coleoptera
2.
Phyllotreta sp.
Coccinellidae
Coleoptera
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Table 3.
Lepidopterous insects as flower visitors/pollinators of different plants
under agro-climatic condition of Haryana
S. No. Scientific name
Family
Order
1.
Chactoprocta odata
Lycaenidae
Lepidoptera
2.
Cosmolvce boeticus
Nymphalidae
Lepidoptera
3.
Danais aglea creamer
Danaidae
Lepidoptera
4.
Danais chrysippus
Danaidae
Lepidoptera
5.
Eurema hecabe
Pieridae
Lepidoptera
6.
Gonepterynx hemmi
Pieridae
Lepidoptera
7.
Papilio demoleus
Papiliondae
Lepidoptera
8.
Papilio polytes
Papiliondae
Lepidoptera
9.
Potanthus rectifasciata
Danidae
Lepidoptera
Table 4.
Hymenopterous insects as flower visitors/pollinators of different plants
under agro-climatic condition of Haryana
Sr. No. Scientific name
Family
Order
1.
Apis cerana indica.
Apidae
Hymenoptera
2.
Apis dorsata F.
Apidae
Hymenoptera
3.
Apis florea F.
Apidae
Hymenoptera
4.
Apis mellifera L.
Apidae
Hymenoptera
5.
Ceratina sexmaculata
Apidae
Hymenoptera
6.
Chalicodoma sp.
Megachilidae
Hymenoptera
7.
Eumenes petiolata
Eumenidae
Hymenoptera
8.
Eumenes dimidiatipennis
Eumenidae
Hymenoptera
9.
Halictus sp.
Halictidae
Hymenoptera
10.
Nomia sp.
Halictidae
Hymenoptera
11.
Megachile cephalotes
Megachilidae
Hymenoptera
12.
Megachile bicolor
Megachilidae
Hymenoptera
13.
Mellisodes sp.
Anthophoridae
Hymenoptera
14.
Pithitis smargdula
Anthophoridae
Hymenoptera
15.
Polistes hebraeus
Vespidae
Hymenoptera
16.
Vespa orientalis
Vespidae
Hymenoptera
17.
Xylocopa pubescence
Anthophoridae
Hymenoptera
18.
Xylocopa fenestrata
Anthophoridae
Hymenoptera
243
Table 5.
Dipterous insects as flower visitors/pollinators of different plants
under agro-climatic condition of Haryana
S. No. Scientific name
Family
Order
1.
Chrysomya bezzaina (Villcneuve)
Calliphoridae
Diptera
2.
Chrysops dispar
Syrphidae
Diptera
3.
Eristalis sp.
Syrphidae
Diptera
4.
Gasterophilus sp.
Gasterophilidae
Diptera
5.
Musca domestica L.
Muscidae
Diptera
6.
Sarcophaga sp.
Sarcophagidae
Diptera
Hence it may be concluded that the first step while underlying any scientific work
pertaining to an insect pest is to know its correct identity and systematic position.
When it is correctly identified, the available information on the biology and habits of that
insect, its most vulnerable stage, the appropriate time and the most suitable method or
methods to control it can be referred to. The knowledge and understanding of the ecological facts, both biotic and abiotic, influencing the population of an insect pest are
necessary for planning the proper strategy for controlling the pest. A lot of attention is
being paid to this aspect now and elaborate procedures and 'models' have been evolved
to pinpoint the 'key factors' dominantly affecting the development and multiplication of a
particular pest. The assignment of a name to an organism provides the only key to all
the information available about the species and its relatives. Thus, careful and accurate
identification and classification are of vital importance.
In science, as in all progressive enterprises, some logical system of grouping or
classifying according to the types, quality or the needs of the material concerned is
necessary. Knowledge of the orders of insects and characters of each provides more
information than any other basic facts of the science of entomology. It is rather impossible to speak of any taxon under consideration of any study or to think lucidly about it
unless it is named. Even the enforcement of the conservation laws, knowledge of the
species involved must be had.
Suggested Readings
Erwin, T. 1982. Tropical forests: their richness in Coleoptera and other arthropod
species. Coleopterists Bull . 36 : 74-75.
Danks, H. V. 1988. Systematics in support of Entomology. Ann. Rev. Entomol . 33 : 271296.
Mayr, E.; Linsley, E. G. and Usinger, R.L. 1953. Methods and Principles of Systematic
Zoology . Mcgraw Hill, New York, 328 pp.
Snodgrass, R. E. 1956. The Anatomy of the Honey Bee. Cornell University Press; Ithaca,
New York, 70 pp.
Stork, N.E. 1991. The composition of the arthropod fauna of Bornean lowland rainforest
trees. J. Trop. Ecol. 7 : 161-180.
244
CENTRE FOR ADVANCED FACULTY TRAINING
DEPARTMENT OF ENTOMOLOGY, CCSHAU, HISAR
Name & ddresses of participants in the training programme on "Advances in
Bio-Ecology and Management of Insect Pollinators of Crop" under Centre of Advanced
Faculty Training (CAFT) form 21.02.2012 to 12.03.2012.