The XX Factor

Every Sperm is Sacred

Don’t you hate it when you accidentally have sex with your sister? This happens to Indian meal moths , a common kitchen pest that feeds on grains and cereals. Being moths, they don’t really care about the moral issues, but offspring of an incestuous moth union are likely to be infertile. And since the moths have only a week get busy before heading off to the Great Pantry in the Sky, they can’t afford too many reproductive dead ends.

But new research, published in this month’s Animal Behavior, shows that male moths can stop worrying about fruitlessly spending their sperm on their sisters. Male Indian meal moths are tantric masters . If they’re getting down with an unrelated lady friend, they give her ejaculate chock-filled with the very finest of sperm. But if they met their sweetie in the next cocoon over, they only release half as many sperm. That way, the moth isn’t wasting energy on a whole Flowers in the Attic scene and can save his sperm for a less related lady.

While many female insects have a built-in morning-after pill that allows them to discard sperm they don’t like , it was thought that male insects just had to thrust and think of England. But apparently even male moths yearn for control over the ultimate fate of their gametes. After all, when a single sperm can make the difference between being a grandpa moth or evolutionary roadkill, every sperm is indeed sacred.

Photograph of mating Indian Meal Moths by Richardus / Wikipedia.