Courtship behaviour in male red-backed salamanders: the ESS dating game ☆

Abstract Social interactions in red-backed salamanders, Plethodon cinereus are complex and often depend upon the sex and reproductive status of individuals. In the population at Mountain Lake Biological Station, Virginia, adult males outnumber sexually active (gravid) females by approximately 2:1, because males court annually while females accept mates only biennially. Field observations of male P. cinereus suggest that males maintain feeding territories and allow non-gravid (not sexually active) females access to their territories for foraging, whereas they defend their territories against intrusion by males. We used a game-theoretic analysis of models of male fitness to examine conditions that would favour the evolution of this ‘permissive’ behaviour. Under a series of increasingly realistic behavioural assumptions, we found that the critical factor in the evolution of male permissive behaviour is female preference for permissive males. If non-gravid females are more likely to return to mate with a male that allows access to his territory, then permissive behaviour is likely to evolve. Furthermore, the evolution of permissive behaviour is facilitated when energetic losses due to territorial defence exceed those due to allowing females to forage.