The role of prey size and abundance in the geographical distribution of spider sociality
Leticia Avilés, Department of Zoology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada (e-mail: email@example.com).
- 1Social species in the spider genus Anelosimus predominate in lowland tropical rainforests, while congeneric subsocial species occur at higher elevations or higher latitudes.
- 2We conducted a comparative study to determine whether differences in total biomass, insect size or both have been responsible for this pattern.
- 3We found that larger average insect size, rather than greater overall biomass per se, is a key characteristic of lowland tropical habitats correlating with greater sociality.
- 4Social species occupied environments with insects several times larger than the spiders, while subsocial species nearing dispersal occupied environments with smaller insects in either high or low overall biomass.
- 5Similarly, in subsocial spider colonies, individuals lived communally at a time when they were younger and therefore smaller than the average insect landing on their webs.
- 6We thus suggest that the availability of large insects may be a critical factor restricting social species to their lowland tropical habitats.