Bees and pollen: what you've always wanted to know

Updated: Mar 11, 2021

thcollection and use of pollen in the honeybee colony.

The colony needs a fertile queen and the pheromone from the open brood to stimulate the foraging bees to collect pollen. Returning foragers recruit further foragers by dancing on the comb the position of the source of pollen; the specific type of pollen is recognised by the aroma of the pollen on the bees legs.

The number of pollen foragers varies considerably between colonies from just a few percent to as much as 90% of the colony.

How a bee forages for pollen.

After a bee has observed the waggle dance performed by other foragers in the colony it leaves the hive and flies to the co-ordinates it has provided. When it arrives it alights on a flower and moving quickly, bites the anthers off the stamen of the flower with her mandibles in order to dislodge the pollen grains. These pollen grains attach themselves to the plumose hairs which cover the whole of the bees exoskeleton. Interestingly the pollen is further helped in attaching to the hairs by the static charge which is built up whilst the bee is in flight, exactly the same as the static charge that is produced when a helicopters rotor blades spin.

Then the bee leaves the flower and hovers nearby to clean the pollen from her body and to load it into her 'pollen baskets', this process is as follows:

a) The front legs: by means of stiff hairs collect pollen from the head and the first thoracic segment. The pollen is moistened with honey or nectar deposited on the front legs by the proboscis.

b) The middle legs: collect the pollen from the front legs and the rest of the thorax particularly the ventral side which is then passed on to the inner side of the basitarsi of the hind legs.

c) The hind legs: clean the abdomen and when sufficient pollen is collected on the inner surface of the basitarsi, these surfaces are then raked by the 'pollen rake' at the bottom of the tibia of the other hind leg. The pollen is then forced as a paste on the flat surface of the auricle which is bevelled upwards and outwards. The tarsus closes against the tibia and the pollen is squeezed upwards and outwards onto the outside surface of the tibia.

it is held in place here by hairs on the corbicula, (pollen Basket) of the tibia which has a single hair acting like a pin through the load. One full load of two pellets represents approximately 100 flowers visited.

Storage of pollen.

When the pollen forager returns to the hive with a load it has to be stored. She selects a cell near to the unsealed brood, grasps the edge of the cell with her forelegs and arches her abdomen so that the posterior end rests on the opposite side f the cell. The hind legs hang into the cell and the middle legs are used to push the pollen loads off the rear legs and into the cell. The forager departs immediately in search of another load. A house bee now takes over the process and breaks up the pollen and presses firmly into the bottom of the cell with her mandibles. Honey or Nectar are added to the pollen mass; it becomes darker, has a higher sugar content and is known as 'bee bread' .

The use of pollen in a honeybee colony.

a) it is the principal source of protein, fat and minerals in the honeybee diet

b) it can provide a surplus product from the apiary.

Pollen demand in the colony is related to the amount of unsealed brood. Bees cannot rear brood without pollen because the nurse bees cannot produce brood food from the hypopharyngeal glands, unless the bee has first consumed pollen. A strong colony will collect c. 50-100lbs during the season.

#pollen #bees

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