The Cape honeybee of South Africa seems at first like an ordinary bee. Like many bees, it lives in a colony where the only fertile individual is the queen, who returns from mating flights to lay eggs containing more workers, each pairing the genes of the queen and her mates. But in certain situations, in which the queen is absent or a worker happens upon another bee subspecies’ hive, a worker bee can rise up. Freed from the hormonal stranglehold that the queen usually maintains over the rest of the colony, she begins to lay eggs.
Each new bee is a perfect clone of herself. When they hatch, the rapidly reproducing clones can take wing and raven through the countryside in search of other subspecies’ hives, where they invade hapless victims’ nests, lay their own eggs, and act as parasites until the host colony collapses. But by then, other copies of the insubordinate worker have been born and flown over the horizon in search of new queens to dethrone.
In a bee, this is monstrously strange. Generally, colonies of bees and other social insects function like a single superorganism, with the many supporting the reproduction of the few. They are all so closely related that this amounts to helping themselves. When a Cape honeybee transforms from a placid social insect into a parasite, it’s doing something that appears outside the natural order. Ever since people discovered parasitic Cape honeybees inside collapsing colonies in South Africa, about a hundred years ago, beekeepers and biologists have considered: How does this happen? In a new paper out in Molecular Biology and Evolution, biologists provide the beginnings of an explanation, revealing that a single blip in the genetic code is the only difference between these bees and their peaceful siblings.