Bee bread

Bee pollen is the pollen ball that has been packed by worker honeybees into pellets. Bee bread is also the bee pollen with added honey and bee secretions and stored in brood cells, chambers of honeybees or of wood and mud created by female ground-nesting (such as the Leafcutting Bee) bees. With the Leafcutting Bee, when the pollen ball is complete, a single female lays an egg on top of the pollen ball, and seals the brood cell. Pollen balls are harvested as food for humans. Bee pollen is sometimes referred to as ambrosia. Where as with Honeybees, the thing to keep in mind is that the forager bees that gather pollen do not eat it themselves, since when they transition to foraging, they stop producing the proteolytic enzymes necessary to digest it. So the foragers unload the pollen they’ve gathered directly into open cells located at the interface between the brood and stored honey, creating a typical band of what is called beebread - the substance which is the main food source for honey bee 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. Bee pollen is the primary source of protein for the hive. This method of packing can be seen in the bee species Xylocopa sulcatipes and Xylocopa varipuncta.

Like honey and propolis, other well-known honey bee products that are gathered rather than secreted (i.e., in contrast to royal jelly and beeswax), the exact chemical composition depends on the plants the worker bees gather the pollen from, and can vary from hour to hour, day to day, week to week, colony to colony, even in the same apiary, with no two samples of bee pollen exactly identical. Accordingly, chemical and nutritional analyses of bee pollen apply only to the specific samples being tested, and cannot be extrapolated to samples gathered in other places or other times. Although there is no specific chemical composition, the average composition is said to be 40-60% simple sugars (fructose and glucose), 2-60% proteins, 3% minerals and vitamins, 1-32% fatty acids, and 5% diverse other components. A study of bee pollen samples showed that they may contain 188 kinds of fungi and 29 kinds of bacteria. Despite this microbial diversity, stored pollen (also called bee bread) is a preservation environment similar to honey, and contains consistently low microbial biomass.

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Wikipedia