Are bee colonies incestuous?

Chris - Well actually, the bees aren't all genetically identical.

What happens is that a queen bee comes out of the nest when she's young and she releases a pheromone and she attracts something like 16,000 male bees called drones.

Those male bees, about 200 of them, that are lucky enough will mate with her and she will collect millions and millions of sperm.

She then goes back to the nest with the sperm and uses it for the rest of her life, maybe 7 years or more, just to fertilise eggs. So she's got a mixture of sperm from different drones there. That's the first point.

The drones are all themselves haploid, in other words, they only actually have one set of genetic material. So all of their sperm are genetically identical and the effect of this is that the worker bees, which are all female actually, because they're not haploid they're diploid, they actually have both male and female chromosomes in them. And as a result, they are all 75% genetically identical to each other.

So if they actually were to start reproducing, they would produce less genetic diversity in the colony than if the queen reproduces by mating with the drone using the sperm she's got stored.

So it's slightly more subtle than you thought and it does actually work very, very well because the bees are a collective colony, the sisters, because they're also so closely related - these workers. They're actually working towards helping the queen to reproduce because then their own genes are being passed on more efficiently than if they were to actually start mating internally within the colony.

The queen does actually police this. She does actually stop the workers trying to reproduce. But, as the queen gets older, this can occasionally begin to happen. It's a sort of escape.