Meeting Abstract

P3-100   -   Uninvited guests: Response of social networks to changing group composition in the maritime earwig Iyengar, VK*; Vipperman, AC; Villanova University; Villanova University vikram.iyengar@villanova.edu

Social networks, described as the structure of interactions between individuals of a population, can aid us in understanding the relationships and processes that occur between individuals, groups, and entire populations. Social network analysis, in turn, can provide insight on the spatial distribution of organisms, selective pressures, and fitness. The maritime earwig (Anisolabis maritima) is an excellent organism for social network studies because these insects are found in high densities under driftwood shelters that lead to frequent, monitorable interactions between individuals. Maritime earwigs exhibit strong sexual dimorphism in terms of temperament and morphology, as females often use their straight pincers for aggressive, lethal strikes whereas males tend to use their asymmetrically curved pincers in non-lethal encounters. These sex-based behavioral differences often manifest within larger groups, where it has been shown that female-biased populations tend to have more rigid, less dense social networks than male-biased ones. However, maritime earwigs join and leave shelters regularly in dynamic ‘fission-fusion’ social systems where group size and composition are in flux. Our study mimicked the variable nature of wild populations by creating equal-sex groups and subsequently incorporating new, different-sex groups. When we examined social network parameters before and after additions, we found that node-based and network-wide attributes remain primarily determined by sex, as aggressive females are more central than their more timid male counterparts. Our results reveal how sex differences in behavior and movement can affect social networks in organisms with fluid population dynamics.