Bees play a fundamental role in ecosystems worldwide. Their diligent work as pollinators enables the reproduction of countless plants, including many that provide food for humans. This process often involves the collection and transport of pollen, for which bees possess specialized adaptations.
How Bees Carry Pollen
Bees, especially honey bees, possess specialized features for pollen transport. The most recognized is the “pollen basket” or corbicula, located on their hind legs. This structure is a smooth, concave area surrounded by stiff hairs. As a bee visits flowers, pollen grains, which often carry an electrostatic charge, adhere to the bee’s hairy body. The bee then uses its other legs and mouthparts to brush the collected pollen towards its hind legs.
The pollen is moistened with a small amount of nectar or saliva, which helps it stick together and form a compact pellet. This sticky pellet is then packed into the corbicula. While honey bees and bumble bees utilize corbiculae, other bee species, such as leafcutter bees, employ dense tufts of hair called scopae, often located on their legs or the underside of their abdomen, to carry pollen. This allows bees to carry loads of pollen, visible as colorful pellets on their hind legs when they return to the hive.
Why Bees Collect Pollen
Bees collect pollen primarily as a food source for their colony. Pollen provides proteins, fats, vitamins, and minerals, important for the growth and development of young bees and the overall health of the adult bee population. Unlike nectar, which is a carbohydrate source providing energy, pollen supplies the necessary nutrients for building tissues and supporting the bee’s physiological processes.
The protein content in pollen can vary significantly depending on the plant source, ranging from 6% to 30% of its dry weight. This protein is important for feeding larvae and newly emerged adult bees, enabling their bodies to complete development. Without an adequate supply of pollen, a colony’s ability to rear new brood and maintain its population can be severely impacted.
Pollen’s Broader Significance
Once pollen is brought back to the hive, it is transformed. Worker bees pack the pollen into honeycomb cells, where it is mixed with honey and bee secretions. This mixture then undergoes a lactic acid fermentation, converting it into “bee bread.” Bee bread is a more digestible and nutritionally enhanced form of pollen, serving as the primary protein source for the hive, especially for feeding larvae. Its composition, including amino acids and minerals, varies based on the floral sources and environmental conditions.
Beyond its role as a food source for the bee colony, the act of pollen collection has an ecological impact. As bees move between flowers, some pollen dislodges from their bodies and is transferred to the stigmas of other flowers. This transfer facilitates pollination, where pollen from a flower’s male part reaches its female part, leading to fertilization and seed production. Bees are responsible for pollinating a substantial portion of the world’s crops and wild plants, making them key for maintaining biodiversity and supporting food webs in various ecosystems.