Lecture 4: ROLE OF HONEY BEES IN CROSS POLLINATION - THEIR
EXPLOITATION - CASE STUDIES WITH SELECTED CROPS
For SEXUAL reproduction in flowering plants transfer of anther to stigma is
essential - Pollination
Self pollination
Transfer to sligma of same plant
No external agents are involved
Cross pollination
Transfer pollen from one plant to stigma of another plant
External agents are involved
External agents involved in pollination
A. Abiotic agents
a. Wind (Anemophily)
Wind carries pollen from one plant to another
Flowers are small, inconspicuous, unattractive
Pollen are dry and light in weight
Stigma feathery with large surface area
eg: Maize, barley, wheat, sugarcane
b. Water (Hydrophily)
Water carries pollen from one plant to other
B. Biotic agents
Bird, bat and insects are important biotic agents
Among insects honey bees play major role
Honey bees and flowering plants have coevolved
In insect pollinated plants, flowers are large, brightly colour, distinct fragrance,
presence of nectar and sticky pollen
True honeybees (Apis spp.) - Most valuable pollinators of commercial crop
Qualities of honeybees which make them good pollinators
1. Body covered with hairs and have structural adaptation for carrying nectar and
pollen.
2. Bees - Not injurious to plants
3. Adult and larva feed on nectar and pollen - Available in plenty
4. Superior pollinators - Since store pollen and nectar for future use
5. No diapause - Need pollen throughout year
6. Body size and probascis length - Suitable for many crops
EXPLOITATION - CASE STUDIES WITH SELECTED CROPS
For SEXUAL reproduction in flowering plants transfer of anther to stigma is
essential - Pollination
Self pollination
Transfer to sligma of same plant
No external agents are involved
Cross pollination
Transfer pollen from one plant to stigma of another plant
External agents are involved
External agents involved in pollination
A. Abiotic agents
a. Wind (Anemophily)
Wind carries pollen from one plant to another
Flowers are small, inconspicuous, unattractive
Pollen are dry and light in weight
Stigma feathery with large surface area
eg: Maize, barley, wheat, sugarcane
b. Water (Hydrophily)
Water carries pollen from one plant to other
B. Biotic agents
Bird, bat and insects are important biotic agents
Among insects honey bees play major role
Honey bees and flowering plants have coevolved
In insect pollinated plants, flowers are large, brightly colour, distinct fragrance,
presence of nectar and sticky pollen
True honeybees (Apis spp.) - Most valuable pollinators of commercial crop
Qualities of honeybees which make them good pollinators
1. Body covered with hairs and have structural adaptation for carrying nectar and
pollen.
2. Bees - Not injurious to plants
3. Adult and larva feed on nectar and pollen - Available in plenty
4. Superior pollinators - Since store pollen and nectar for future use
5. No diapause - Need pollen throughout year
6. Body size and probascis length - Suitable for many crops
