EXPERIMENTAL MANIPULATIONS OF SOCIAL TENDENCIES IN THE SUBSOCIAL SPIDER COELOTES-TERRESTRIS

In the subsocial terricolous spider Coelotes terrestris, the young usu ally leave the maternal tube and disperse after a 4-6-week gregarious period. In the present experiment they were artificially prevented fro m dispersing, while being liberally provided with prey. Under such con ditions they appeared to maintain a certain level of organization: rep roduction, structured silken production, and stabilized mortality. Thi s last characteristic was shown, using specifically designed tests, to be due to a higher tolerance level in group-maintained as compared to freely dispersed, adult spiders. The influence of social situations o n tolerance tendencies was further assessed (together with the determi ning influence of the mother) by prematurely separating spiderlings fr om their brood. Such phenomena may be considered evidence of preadapta tions to permanent social life in this subsocial species.