Evolution of Social Behavior in Spiders (Araneae; Eresidae and Theridiidae)

Whereas most spiders are asocial, species in eight families are known to live all their life in communities and are thus “permanent-social.” Their special attributes are: tolerance, interattraction, and cooperation. These peculiarities must have been achieved step by step several times independently. Periodic-social spiders have been studied as a link between asocial and permanent-social spiders. In two families—the cribellate Eresidae and ecribellate Theridiidae—different steps of periodic sociality have been discovered, from brood-care to feeding by regurgitation. The comparative study of the phylogeny of social behavior in both families uncovers remarkable convergences of patterns from asocial to permanent-social via periodical-social species of spiders.