The Communal Lifestyle of Web-Building Spiders in Tropical Forests

Abstract

Most web-building spiders build their webs solitary, and they usually prevent other individuals from invading their webs. However, some web-builders make their webs communally, and these are found mostly in tropical rain forests. The advantage of communal web building is thought to be improved prey capture. The communal capture of large insect prey has been observed in a number of social web-building spiders and communal spiders have been shown to capture larger prey than do solitary spiders. Philoponella raffrayi is a communal web-building uloborid spider that is distributed throughout southeastern Asia. This study describes the colony composition, and prey capture and handling behavior of the uloborid spider P. raffrayi. It determines whether the efficiency with which this species captures large insects is higher when spiders hunt cooperatively than when they hunt alone. Although most prey was captured by individual spiders, I occasionally observed two spiders cooperatively wrapping and capturing prey. Cooperation increased prey-capture efficiency when the prey was larger than half of a spider’s body length. Furthermore, interspecific associations of P. raffrayi in the Pasoh Forest Reserve (Pasoh FR) is described.