Seasonal and geographic variation in territorial conflicts by male red-backed salamanders

Abstract

We studied seasonal and geographic variation in the territorial behaviour of male red-backed salamanders, Plethodon cinereus. We examined tail loss in the forest and aggressive and submissive behaviour in the laboratory during summer (non-courtship season) and spring and autumn (courtship seasons) at two localities in Virginia, USA. In both populations, the proportion of tail loss was highest during the spring, while aggression was higher in the summer than in the spring or autumn. Thus, aggression was not directly associated with male–male contests for females or to tail loss. Secondly, we examined geographic variation using males from eight populations varying in elevation, genetic relatedness (two genetic groups), and presence/absence of similar-sized congeners. Behaviour differed based on elevation and genetic group: residents from lower elevations were more submissive and males from one genetic group were more submissive than those from a second genetic group. Therefore, resident-intruder behaviour varied seasonally and geographically.