Two cooperatively social populations of the theridiid spider Anelosimus studiosus in a temperate region.

Social spiders are typically found only in the tropics. In laboratory tests and field observations, adult female A. studiosus in two populations in Tennessee, U.S.A., a temperate region, showed inter-attraction (grouping behaviour caused by the presence of conspecifics), greater tolerance towards conspecifics, and cooperation during prey capture and brood care. These are the three classical conditions considered typical of social spiders. The populations also had female-biased sex ratios and limited dispersal. Anelosimus studiosus can thus be regarded as a quasi-social or cooperative spider species. These populations of A. studiosus are the first social spiders to be described from typically temperate regions. Copyright 1998 The Association for the Study of Animal Behaviour Copyright 1998 The Association for the Study of Animal Behaviour.