Honey Bees and Pollination:
A. Parts of the Flower
http://www.agen.ufl.edu/~chyn/age2062/lect/lect_15/22_62.GIF
1. A perfect flower contains both stamens (male parts) and pistil (female parts).
2. An imperfect flower contains only male or female parts.
3. Inflorescence – an arrangement of flowers on a stem
4. Floret – one flower
5. Monoecious – plants that have both male and female flowers on the same plant
6. Dioecious – plants that have only one sex of flower on the same plant
B. What is pollination?
1. Pollination – the transfer of pollen from the anthers of a flower to the stigma of
the same or different flower
2. Fertilization – when male genetic material passes down the pollen tube and
reaches an ovule
3. Flower receptivity – the time period in which a female flower is open and can
be fertilized
Examples: 1 day for seedless watermelon; 7 days for blueberry
Fertilization
C. Types of fruits
1. Berry – fleshy outer wall surrounding one or more fairly small seeds.
Example – blueberry
2. Pome – fleshy outer wall surrounding a tough core with seeds.
Example – apple
3. Drupe (stone) – fleshy outer wall surrounding one stony seed
Example – peach, cherry
4. Aggregate – many pistils develop together as a single mass
Example – blackberry, strawberry
Fruit Set – the proportion of flowers that successfully produce fruit
a) may require multiple pollination events
Example: It takes 24 bee visits to sufficiently pollinate a seedless
watermelon flower and form quality fruit.
D. How does pollination occur?
1. Wind
2. Mechanical transfer (usually insects)
3. Wind pollinated plants – Examples: pine trees and grasses
a ) produce many small pollen grains
b) don’t disperse well, occur in stands
c) advantage – does not require a pollinator
4. Mechanical Transfer
a) Types of Pollinators:
1) Birds
2) Bats
3) Insects: Examples: Bees, Butterflies, Beetles, True Bugs,
Flies
5. Insect Pollinated Plants
a) Mutualistic relationship between the plant and the pollinator – produce
rewards
b) Have nectarines
c) Produce less pollen and have larger pollen grains
6. Pollinator Rewards
a) Pollen – lipid, starch, or protein
b) Nectar – sugar solution
c) The plant must provide adequate rewards to promote foraging by the
pollinator but not so large a reward that it discourages movement to
other flowers.
E. Why do pollinators seek rewards?
1. Foraging Energetics:
intake energy – output energy = Net energy gain
2. Output Energy:
a) Distance – How far away is the foraging area?
b) Discrimination Time – How long does it take to travel from flower to
flower?
c) Handling Time – How much time does it take to work the flower to get
nectar and pollen?
3. Intake Energy:
a) Quality of rewards – sugar content of nectar
F. Cross-pollination
1. Self- sterility – plants that require pollen from a different plant or even a
different variety
2. Cross-pollination - the transfer of pollen from flowers of one plant to the
flowers of a different plant or different variety
3. Pollenizer - variety interplanted within main variety to provide crosspollination
4. Cross-pollination benefits
a) Higher % fruit set
b) Larger Fruit
5. Choosing varieties
a) Do your homework!
b) Choose varieties that will bloom at the same time.
Examples - Blueberries – Premier and Climax;
Seedless Watermelons – Sugar Heart and Crimson Sweet
c) Planting Schemes
1) Every other tree is a pollenizer
2) Every third tree in every third row is a pollenizer
3) Think about hive placement
G. Special Cases:
1. Self-fertile – plants that can develop seeds and fruit when pollen is transferred
from anthers of a flower to the stigma of the same flower or
different flower on the same plant
2. Self-pollinating - plants that do not require insects to move pollen to the
stigmas
3. Parthenocarpic - plants that develop fruit without requiring the pollination
process
H. What makes a “good” pollinator?
1. Carries a high percentage of donor pollen.
2. Visits a high percentage of receptive stigmas.
3. Visits pollen-donor and pollen-receiver flowers successively.
4. Covers stigmatic surfaces.
5. Works rapidly.
6. Works long hours.
I. Why are honey bees good pollinators?
1. Large numbers – large colony size, lots of individuals, large foraging force
2. Generalists – forage on a wide variety of plants
J. Minimum hive strength standards
1. Bees blanket tops of 6-10 frames
2. Brood fills 4-6 frames, preferably young brood
3. Queenright
4. No uncontrolled diseases or parasites.
K. Hive placement
1. The optimum foraging distance from the colony is 300ft. (Remember foraging
energetics)
2. Spacing colonies 500ft apart will maximize optimum foraging distance and
give better coverage, but difficult and not always practical to do this.
3. Most hives for pollination are placed on the edge of the field. Placing colonies
side by side in close proximity will increase the foraging distance and push
bees further into the field. Competition increases field coverage.
4. Naïve honey bees generally perform best. Moving bees into an area after the
bloom has begun will increase the chance that bees will forage in that area.
Bees that have been in the area for awhile have already found other forage and
may overlook the target crop.