O.K., in my roundabout way, I’m finally going to get to my point. Bees not only store pollen and honey in the combs, but they also store food reserves in their bodies. This is done mainly in the form of a compound called “vitellogenin.” vitellogenin is classed as a “glycolipoprotein,” meaning that is has properties of sugar (glyco, 2%), fat (lipo, 7%), and protein (91%) (Wheeler & Kawooya 2005). Vitellogenin is used by other animals as an egg yolk protein precurser, but bees have made it much more important in their physiology and behavior, using it additionally as a food storage reservoir in their bodies, to synthesize royal jelly, as an immune system component, as a “fountain of youth” to prolong queen and forager lifespan, as well as functioning as a hormone that affects future foraging behavior!
This is a great example of the conservatism of evolution. Just as the same genes that code for a fish’s fins also code for a dog’s paw, a human hand, or a bird or bat’s wing, bees have expanded the role of vitellogenin to perform multiple functions in their systems. They are able to do this because most of the bees in a colony are sterile females who rarely lay eggs. Therefore, they have the mechanism to produce this egg yolk precurser, but no use for it. So instead, they deposit it in fat bodies in the abdomen and head.***