Summary: Journal of Animal
© 2007 The Authors.
© 2007 British
Blackwell Publishing Ltd
The role of prey size and abundance in the geographical
distribution of spider sociality
KIMBERLY S. POWERS* and LETICIA AVILÉS*
*Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721, USA, Department of
Zoology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; and David Evans and Associates, Inc.,
2100 River Parkway, Portland, OR 97201, USA
1. Social species in the spider genus Anelosimus predominate in lowland tropical rain-
forests, while congeneric subsocial species occur at higher elevations or higher latitudes.
2. We conducted a comparative study to determine whether differences in total biomass,
insect size or both have been responsible for this pattern.
3. We found that larger average insect size, rather than greater overall biomass per se,