Meeting Abstract
63.8 Wednesday, Jan. 6 Can temperature drive the intensity of male-male competition across a latitudinal cline? CAMERON, S. F.*; WILSON, R. S.; The University of Queensland, Australia; The University of Queensland, Australia s.cameron3@uq.edu.au
Theory predicts that increased competition for resources should lead to a higher level of intensity of male-male combat in highly territorial species. Environmental temperature has the potential to indirectly drive such increases in competition via changes in population density, activity and aggressive behaviour. However, the role temperature plays in mediating the intensity of competition and sexual selection among populations is relatively unknown. In this study, we investigated the intensity of male-male combat and sexual dimorphism among populations of the Asian house gecko (Hemidactylus frenatus) along a latitudinal cline. Asian house geckos are a highly invasive species that have recently dispersed across Australia, from the tropics to temperate regions. Males of H. frenatus are also highly territorial and frequently engage in intense disputes and physical fights. We quantified the influence of temperature on the level of activity, aggression, sprint performance and maximum bite performance in males of H. frenatus. In addition, we quantified the level of male-male aggression, activity and competitive signalling along their latitudinal distribution. Finally, we assessed the extent of sexual dimorphism in body and head size among populations and determined their functional consequences for sprint and bite performance. We predicted there would be higher levels of male-male aggression in warmer environments and this would be associated with increased sexual dimorphism. As expected, acute increases in temperatures resulted in higher levels of activity and aggression and better whole-animal performance. We also found marked differences in the level of male-male aggression among the populations and their relationship to sexual dimorphism will be discussed.
