Abstract

Using research done in my group on social spiders, I will illustrate how sociality—group living and cooperation—arise as a result of an interaction between intrinsic features of the organisms and the environments in which they live. I will show how the dense tridimensional webs that characterize the genera where social spiders have originated may interact with environmental factors such as insect size, predation rate, and precipitation intensity to determine the geographical distribution of spider sociality. I will also show how, in turn, group living and cooperation may become an axis for niche differentiation, thus potentially playing a role in the assemblage of natural communities. I will illustrate the latter point by analyzing communities of the spider genus Anelosimus across the Americas to test the hypothesis that their composition in terms of species’ body size and level of sociality is more over-dispersed than expected by chance.