Mating behaviour and sexual selection in non-lekking fallow deer (Dama dama)

Abstract: This thesis examines both behavioural and morphological traits influencing male mating success in non-lekking fallow deer (Dama dama). The thesis contains results based on behavioural observations and experimental studies made on Öland and around Uppsala, Sweden.In an initial observational study I found evidence that scent marking may be involved in male competition. While scent marking is an almost universally occurring phenomenon among mammals, the exact function of the scent marks is poorly understood. In an experimental study I found evidence supporting the hypothesis of scent marks being used by fallow deer males for status advertisement. If challenged, males were found to increase scent marking, and males with high rates of scent marking were subjected to fewer agonistic encounters than those with low scent marking rates. In addition I found a positive correlation between scent marking during the early stages of the rut and mating success during the peak of the rut, indicating a possible fitness benefit of scent marking to the males in terms of increased mating success.The optimality argument that first reproduction occurs at the age when the benefits of reproduction outweigh the costs implies that if conditions change, age at first reproduction should also change. In an experimental study in which we examined the response of different aged males to changes in the level of competition, evidence was found supporting this hypothesis. Our results suggest that male social dominance is the most important determinant of the level of participation in the rut for male fallow deer.A negative relationship between trait size and fluctuating asymmetry has been proposed as indicative of trait size being an honest signal of male quality. Using an extensive literature data set I found this relationships to be negative in two species, and positive or flat in two species. Thus, quality signalling through size and fluctuating asymmetry in antlers does not seem to be a ubiquitous mechanism in deer species.