Meeting Abstract
Although testosterone (T) is typically a primary mediator of male aggression in lizards, Caribbean Anolis lizards do not all seem to follow the rule of more testosterone-more aggression. We manipulated non-steroid hormones to determine what might mediate behavior in a low-T-high-aggression species (Anolis sagrei), as well as to determine whether similar responses would be observed in a high-T-high-aggression species (A. cristatellus). Following a 3-week period of acclimation in the laboratory, 17 male A. sagrei and 14 male A. cristatellus were randomly assigned experimental groups (arginine vasotocin, mesotocin, or saline IP injection), using standard doses. Behavioral responses to a mirror were video-recorded for 20 min after a 15-min acclimation period. Analysis of the responses noted the type(s), frequency and duration of aggressive bouts for each individual. We then compared the experimental groups to the controls before making a comparative analysis between the species. In A. sagrei, mesotocin-injected lizards tended to be less aggressive than the other treatments, but much more variable. In A. cristatellus, mesotocin-injected lizards also had more variable responses, but they tended to be more aggressive than the other treatments. Our results suggest that more than just T signaling may be responsible for variation in aggression among Caribbean anole species.
