23.6 Wednesday, Jan. 4 It takes all kinds :Iterative evolution of increased trait variance proves advantageous for spider societies PRUITT, JN*; OUFIERO, CE; AVILES, L; RIECHERT, SE; University of Pittsburgh; University of California, Davis; University of British Columbia; University of Tennessee, Knoxville Agelenopsis@gmail.com
The evolution of sociality is often regarded as a key transition, in part, because group-living is thought to change the adaptive landscape in which ancillary traits evolve. Here we investigate the behavioral correlates of sociality across a clade of polyphenic social spiders in genus Anelosimus. We then experimentally evaluated these trait shifts by staging associations among individuals possessing the hypothesized ancestral character state in four exemplar species. We found that social species tended to be less aggressive towards prey and predators and exhibited lower activity-levels relative to their subsocial ancestors. Additionally, social species exhibit greater trait variation relative to subsocial species. In staged group prey-capture events, groups of non-aggressive individuals outperformed groups of aggressive individuals. Furthermore, groups composed of a mixture of non-aggressive and aggressive individuals outperformed either monotypic group, suggesting the increased trait variance within spider societies is, in fact, functionally adaptive.