Meeting Abstract
Dispersion patterns within a group can reveal important aspects about social interactions and sexual selection within a species. We examined the distribution patterns of the maritime earwig Anisolabis maritima, an insect well-suited for studies of aggression and sociality (both sexes live in close proximity and possess weaponry) and sexual selection (males possess asymmetrical, curved forceps whereas females have straight forceps). We first examined single-sex and mixed-sex groups of 18 earwigs in large enclosures to determine whether they had random, uniform, or clumped distributions. Similar to our field observations, males tended to form aggregations similar to leks whereas females were distributed uniformly, a pattern indicative of territoriality. Mixed-sex groups were initially uniform and then become clumped, and patterns suggest that females behave consistently across contexts while males alter their behavior in response to females. We also conducted trials among three earwigs with limited access to shelters to determine how intra- and intersexual interactions at the individual level may influence overall distribution patterns. In single-sex trios, we found that females exhibited stronger size-based intrasexual aggression than males, as small females were more likely to be excluded from shelters than large females whereas males were more likely to cohabitate with other males. In mixed-sex trios, we found that individuals of both sexes tended to cohabitate with the smaller of two different-sized opposite sex partners. However, a closer examination of the participants suggests different mechanisms driving this similar pattern, which further reflects sex and size-based differences in aggression that may influence the mating system.
