Biology and Demography of Ephestia kuehniella (Pyralidae: Lepidoptera)
80
1
60
0.75
Survivorship
Abstract
Ephestia kuehniella z. is a major stock pest not only in Iran but also around the
world which attacks a large number of products in stocks and damages them.
Flour moth (E. kuehniella) is very important and is used as a leading laboratory
host in breeding and mass production of parasitoid wasps of Trichogramma
genus and some other predators. Life table of Flour moth was studied at
temperature of 25±0.5°C, humidity of 50 ±0.5% and in darkness and flour and
yeast as the food. The obtained data were analyzed according to conventional
life table. Intrinsic rate of population growth (rm), finite rate of population growth
(λ), net reproduction rate (R0), gross reproduction rate (GRR), mean generation
time (T), doubling time (DT) were respectively 0.0683 days, 1.0707 days,
133.861 female offspring, 1147 female eggs, 71605 days, and 10135 days.
Egg per female
Z. Moghadamfar1, M. Amir-Mafi2 and H. pakyari1
1- Department of plant protection, faculty of Agriculture, Islamic Azad University, Takestan Branch- Iran, pakyari@tiau.ac.ir.
2- Sunn pest Research Department, Iranian Research Institute Of Plant Protection, Tehran, Iran
40
20
0
0.5
0.25
0
0 1 2 3 4 5 6 7 8 9 101112131415161718
Adult age (days)
0 1 2 3 4 5 6 7 8 9101112131415161718
Adult age (days)
Key words Ephestia kuehniella , Biology, Demography
Fig. 5. Daily egg production of adult
mediterranean flour moth at 25 °C.
Introduction
The Mediterranean flour moth, Ephestia kuehniella Zeller, 1879 is a serious
cosmopolitan pest of stored products, particularly cereal mills (Rees 2003) and
its eggs are used to rear parasitoids and predators for biological control
programs (Tavares et al. 1989, Viera et al. 1992).
The improvement of mass rearing is dependent on the knowledge of
rereproductive capacity and related biological traits. Therfore, the objectives of
this study were, to estimate basic demographic parameters that could be used in
mass rearing program and control research.
Survivorship of female is given in fig. 6. No females died during the first 3 days.
After 7 days about 60% of the original female cohort was alive. Those remaining
females continued to live for 10 days.
Summary statistics of the adult characteristics are given in table 1. the
expectation of life at female eclosion was 8.53 days. Gross and net fecundity
were 392 and 295 eggs/female respectively. A female living to her maximum life
span laid 90% fertile eggs. Net fertility was 32% less than was gross fecundity.
Of this percentage, 22%was due to adult mortality and 10% due to infertility. In
short, adult mortality played larger role than infertility in reducing gross
reproduction.
Materials and Methods
Insect's colonies: E. Kuehniella were reared for 2 generation in metal boxes
(30 × 20 × 5 cm) each filled with 1 kg of a standard diet (970 g of wheat flour
and 30 g of brewer’s yeast for 250-300 pyralid eggs (Attaran 1996) (Fig. 1).
Temperature and relative humidity was maintained in an incubator at 25±0.5⁰C
, 50±% RH and in darkness (Fig. 2).
Life Table: For the life table study, 100 eggs laid within 4 h randomly, were
collected from colony by fine brush. Eggs were individually placed on standard
diet (2 g) in plastic Petri dishes (5 cm in diameters and 1 cm in depth) (Fig.
3)..
All Petri dishes were kept in an incubator under the same conditions as
described above. The survival and developmental stage were checked daily.
As adult moths emerged, males and females were paired in plastic vials (5.5
cm in diameters and 5 cm in depth) that its bottom end was covered by fine
mesh net (Fig. 4) and provided with sugar water (10%). The daily survival of
each individual and fecundity of each female fecundity were recorded daily
until the death of all individuals.
Population parameters, life and fertility tables were estimated following the
methods described in Carey (1993).
Fig. 2
Fig. 6. Age specific survival.
Table. 1. Summary statistics of adult life history trait
General trait
Survivorship
Fecundity
Egg hatch
Fertility
Parameter
Expectation of life at eclosion
Gross fecundity
Net fecundity
mean eggs per day
mean age of fecundity
Gross hatch
Net hatch
mean age hatch
Gross fertility
Net fertility
mean fertile eggs per day
mean age of fertility
Value
8.53 (days)
392 (eggs)
295 (eggs)
23 (eggs)
5.12 (days)
90%
90%
7.5 (days)
353 (eggs)
265 (eggs)
20.7 (eggs)
5.12 (days)
Table. 2. Population parameters
GRR
207.8422682 (offspring)
R0
60.10627561 (offspring)
rm
0.063765093 (d-1)
λ
1.065841996 (d-1)
T
64.23756387 (day)
DT
10.87032331 (day)
Fig. 1
Fig. 3
Fig. 4
Results
The Mediterranean flour moth, Ephestia kuehniella Zeller, 1879 is an important
pest of cereal mills and its eggs are used widely to rear Trichogramma spp. for
biological control programs in Iran.
Eggs: Eggs are laid singly. They are ellipsoid and white when laid, turning light
yellow as embryo develops. The time taken for the eggs to hatch at 25 °C, ranged
from 1 to 7 days. The mean developmental time was 4.27±0.11 d.
Larvae: Larvae are cream coloured and sparsely covered with long hairs. E.
kuehniella have six instars. After hatching enter the infested flour, begin feeding
and remain unseen. At 25 °C, mean developmental time of larvae was 46.9±1.96
d. (ranged 35-81 d.).
Pupa: E. kuehniella pupate in silken cocoons. Mature larvae crawl to the surface
of flour, and spin silk cocoons. Pupae are pale green at the early stage and then
turn to reddish brown and at the last day of development pupae become dark in
colour. At 25 °C, mean developmental time of pupa was 9.19±0.69 d.
Adults: E. kuehniella females are ready to mate and lay eggs when the emerge,
but egg production began after 1 day. The number of eggs per female peaked at
3 days, then it decreased steadily from day 4 to 14 and tapered off to zero after
this time (Fig. 5).
Population parameters. The intrinsic rate of increase and the net reproductive
rate were 0.0.0638 and 60.106, respectively, indicating a daily increase of 6.38
% and a 60-fold increase from generation to generation. The population size
was estimated to double in ~11 d., while the mean generation time was 164.23
d..
References
ATTARAN, M.R. 1996. Effect of laboratory hosts on biological attributes of
parasitoid wasp Bracon hebetor Say. M.S. THESIS, Tarbiat Modarres University,
Iran.
CAREY, J. 1993. Applied demography for biologists. Oxford University Press,
New Yourk.
REES, D. 2003. Insects of stored products. CSIRO Publishing, London. 181 pp.
TAVARES, J., ANUNCIADA, L., OLIVEIRA, L. and VIEIRA, V. 1989. Produção
em massa da Ephestia kuehniella Zeller (Lep., Pyralidae). III - Metodologia para
a avaliação da produção de adultos e ovos. Bolm. Soc. port. Ent. 104: 13-24
VIEIRA, V., TAVARES, J. and DAUMAL, J. (1992): Influence des temperatures
alternées sur le developpement larvaire d'Ephestia kuehniella Zeller (Lep.,
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