By Susan Milius
Acts of apparent altruism in European paper wasps can be explained by plain old self-interest, a new study finds.
Polistes dominulus females can either establish their own nests to raise young or join other females for joint homemaking. In those joint nests, though, one female fights her way to the top and does most of the egg-laying while the others do most of the drudge work in taking care of the top wasp’s young.
When a subordinate helps her sister, that’s not hard to explain: The underling may not end up with her own offspring, but her reproductive success includes an indirect share of her sister’s brood, because relatives share genes. Forgoing her own direct offspring counts as a kind of altruism, in which an individual helping kin trades direct for indirect benefit. Either way, the wasp’s self-interest is served.