Bees play a significant role in ecosystems worldwide. Their interaction with flowering plants facilitates pollination, which is fundamental for plant reproduction and the production of many fruits, vegetables, and seeds. Bees diligently collect pollen, a substance essential for their own survival and the well-being of their colonies.
How Bees Collect and Store Pollen
Bees have specialized anatomical features for efficient pollen collection and transport. As a bee moves among flowers, its fuzzy body attracts pollen grains, often aided by electrostatic forces that cause them to cling to its hairs. The bee then grooms itself, brushing collected pollen towards specific carrying structures.
Honey bees and bumble bees utilize corbiculae, commonly known as pollen baskets. These are concave, polished areas on the outer surface of their hind legs, bordered by stiff hairs. The bee moistens pollen with nectar or saliva, creating a sticky pellet. It then uses leg movements and a “pollen press” to compact and push this pellet onto the corbicula. Each hind leg can carry a single, often brightly colored, pollen pellet, which can weigh up to 35% of the bee’s body weight.
Other bee species, particularly solitary bees, use a scopa. A scopa is a dense mass of elongated, branched hairs, typically found on the hind legs or, in some species like mason bees, on the underside of the abdomen. Unlike the corbicula, the scopa does not form a compacted pellet; pollen grains are held loosely within these specialized hairs.
Why Bees Carry Pollen
Bees collect pollen primarily as a food source for their colony, providing nutrients for growth and development. Pollen is a rich dietary component, supplying essential proteins, lipids (fats), vitamins, and minerals that bees require. The protein content in pollen can vary significantly, ranging from 6% to 30% of its dry weight, depending on the floral source.
This protein is important for the growth of larval bees, enabling their development into healthy adults. Nurse bees within the hive consume pollen to produce royal jelly, a special secretion used to feed young larvae and the queen bee. Pollen also contributes to the overall health and longevity of adult bees and supports the queen’s egg-laying capacity.
Pollen’s role differs from that of nectar, which bees collect as their primary source of carbohydrates. Nectar provides the quick energy needed for activities like flight and hive maintenance. While nectar fuels the bees’ daily tasks, pollen ensures the structural and developmental needs of the entire colony are met.
Pollen’s Arrival at the Hive
Upon returning to the hive, a foraging bee unloads its pollen pellets by scraping them off its hind legs into empty honeycomb cells. House bees, often younger workers, then prepare this collected pollen. They pack it tightly into the cells, often using their heads to compact it.
During packing, pollen is mixed with nectar or honey and bee saliva, which contains enzymes. This mixture then undergoes a natural fermentation process, primarily driven by lactic acid bacteria and yeasts. This transformation converts the raw pollen into “bee bread,” a more digestible and nutrient-enhanced form.
Bee bread is a crucial food for various members of the colony. Nurse bees consume it to produce brood food for larvae. The queen bee also relies on bee bread for her nutrition, supporting her egg production. This stored and fermented pollen ensures the colony has a consistent supply of protein and other nutrients, especially during periods when fresh pollen is scarce.