Testing mating systems and sexual selection theories in a polygynous model system

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Sexual selection has been widely studied, but it remains controversial, partly because the foundations of the theory are still largely untested. While many components of sexual selection (e.g. aggressive competition, mate choice and sexual conflict) have been clarified, most studies focus principally on insects and birds, taxa with peculiar life histories. Ultimately we need similar evidences from other taxa, including mammals, for which theoretical and experimental work is lacking. Moreover, some major unsolved issues exist, such as the mechanisms that favor conspicuous secondary sex ornaments and signals; an understanding of the evolution of female preferences, or the evolution of mating systems. Building from our experience working on the reproduction ecology of a reindeer (Rangifer tarandus) population for more than 10 years, my research team will address the above mentioned gap in order to move the field forward. My research program will test the key predictions of mating systems theory, including the underlying mechanisms of sexual selection. More specifically, over the next 5 years, my students and I will: (1) determine whether females compete for mates, use alternative mating strategies and exhibit mate choice; (2) establish to what extent the intensity of male-male competition and male mating tactics change with the operational sex ratio (the ratio of males to females that are ready to mate); (3) evaluate the potential for postcopulatory sexual selection in reindeer; determine (4) how female density influences mating group dynamics and mating tactics, and how they in turn (5) affect the opportunity for sexual selection. My research program uses a combination of approaches (manipulative large-scale field experiments; long-term individual based demographic data, and observational field work) to test fundamental aspects of mating systems theory that is also relevant to wildlife managers. Taking advantage of our unique study population (e.g. fully-controlled GPS-based population, with a known pedigree), the proposed research will enhance our understanding of the evolution of mating systems while shedding light on critical aspects of female sexual selection that have been overlooked. The research has management implications by exploring how population density influences the distribution of male mating success and population productivity, and by providing information necessary for long term conservation. By testing the sperm quality hypothesis, reindeer herders may use our results to select their breeding males. The project will also contribute to the training of highly qualified personnel (2 PhD, 4 MSc and at least 5 BSc) in behavioural ecology, evolutionary ecology, as well as wildlife conservation and management. In addition, the students will gain invaluable field experience while working in the circumpolar North, and in an international environment.