We don't usually think of spiders as social. In fact, most are not. Even mating can be a dicey proposition. However, some degree of sociality has evolved in some spiders, including the local huntsman (Delena cancerides), which lives in family groups. The Delena genus is particularly interesting for the study of spider sociality, because it has been lost in a closely related spider species. This project will aim to understand what makes spider social, particualrly focusing on the hypothesis that aggression is mediated by metabolic rate, in other words, pro-social behavior can evolve by selection on metabolism. The project will use comparative physiology, gene expression and possibly population genetics to test this hypothesis.