Both experimental and theoretical approaches are used. In many species of social Hymenoptera workers cannot mate but possess ovaries. Because of haplodiploidy any unfertilized eggs they lay are male. In some species of social Hymenoptera, such as bumble bees and Dolichovespula wasps, many of the colony's males are workers' sons. In other species, such as the honey bee and Vespula wasps, very few of the colony's males are workers' sons.
Worker bees eat eggs laid by other workers but leave eggs laid by the queen.
Inclusive fitness studies have shown that worker policing is favored by natural selection when queens are inseminated by more than two males, as in the honey bee and Vespula wasps. Many animals spend part or all of their life in a social group. For example a bird family, a colony of honey bees or other social insects, the brood of a parasitic wasp developing within a single host. A variety of techniques, such as game theory and inclusive fitness modeling, can be used to build simple mathematical models of social behavior. My particular interest is studies of reproductive behavior, conflict and cooperation.