Bee pollen, also known as bee bread and ambrosia, is a ball or pellet of field-gathered flower pollen packed by worker honeybees, and used as the primary food source for the hive. It consists of simple sugars, protein, minerals and vitamins, fatty acids, and a small percentage of other components. Bee pollen is stored in brood cells, mixed with saliva, and sealed with a drop of honey. Bee pollen is harvested as food for humans and marketed as having various, but yet unproven, health benefits.
In honeybees (Apis species) pollen is stored in the chambers of the hives. It differs from field-gathered pollen as honeybee secretions induce a fermentation process, where biochemical transformations break down the walls of flower pollen grains and render the nutrients more readily available.
Forager bees that gather pollen do not eat it themselves, since they stop producing the proteolytic enzymes necessary to digest it when they transition to foraging. The foragers unload the pollen they gather directly into open cells located at the interface between the brood and stored honey, creating a typical band of what is called bee bread – the substance which is the main food source for honeybee larvae and workers.
Foraging bees bring pollen back to the hive, where they pass it off to other worker bees, who pack the pollen into cells with their heads. During collection and possibly packing, the pollen is mixed with nectar and bee salivary secretions, signalling the start of the lactic fermentation process. Bee pollen is the primary source of protein for the hive.
Bees other than Apis typically form pollen into balls; these are primarily ground-nesting bees or twig-nesting bees, most of which are solitary, such as leafcutter bees. With the leafcutter bee, as in most such bees, when the pollen ball is complete, the female lays an egg on top of the pollen ball, and seals the brood cell. The egg hatches and the larva consumes the pollen directly; the pollen is not stored separately from the brood.