Policing egg laying in insect colonies

Kinship by itself can't explain the vigilante justice of some ant, bee, and wasp workers, according to a new analysis of colony life.

In a classic social-insect colony, laying eggs is the job of the queen or queens, though in many species, the workers occasionally lay eggs too. In a practice known as policing, other workers, which are all female, often destroy their nestmates' eggs or even attack a fellow worker caught in the act of egg laying.

Because they are unfertilized, eggs laid by workers and that do hatch only yield sons. That has led many researchers to a potential explanation for egg policing: The workers who do the killing are more closely related to the queen's sons, which are their brothers, than they are to their nestmates' sons, which are nephews.

To test the power of that explanation, Robert L. Hammond and Laurent Keller of the University of Lausanne in Switzerland analyzed colony observations and genetic data from their own studies as well as from