Meeting Abstract

P3.19  Sunday, Jan. 6  Meathead queens: Lethal fighting linked to larger heads in Messor pergandei BESPALOVA, IOULIA*; HELMS, KEN; Arizona State University; University of Vermont ibespalo@asu.edu

In certain populations of Messor pergandei, colony foundation entails obligate lethal fighting between queens. In such populations, queens cooperate with each other in digging nests and rearing the first brood, but reduce to one queen through lethal fighting shortly after workers emerge (secondary monogyny). This fighting behavior is not present in other populations of the same species, where queens either cooperate for the entire life of the colony (primary polygyny) or remain solitary (haplometrosis). We examined whether the necessity of fighting resulted in differences in head width, a proxy for mandible strength, in queens from these three behavioral regions. Workers and newly-mated queens were collected from two sites exhibiting primary polygyny, two sites exhibiting secondary monogyny, and one site exhibiting haplometrosis. Log of head width and hind femur, alinotum and first gaster segment length were measured and regressed against each other using Standard Major Axis (SMA) regression, then linear slopes and elevations were compared among sites. Queens from sites exhibiting lethal fighting were found to have wider heads at a particular alinotum, hind femur, and first gaster segment length, while workers did not show a clear or significant distinction in regression lines between populations with fighting and non-fighting queens. This trend indicates that M. pergandei queens in populations which exhibit secondary monogyny have evolved stronger mandibles in response to the necessity of lethal fighting during colony founding.