Causes, mechanisms and consequences of female competition in red-fronted lemurs

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In the context of mammalian reproduction, female competition is much more pervasive than assumed by classical sex role theory. Episodic targeted aggression among females, which may result in eviction and even death, has been intensively studied in carnivores, but comprehensive field studies of primates are lacking. Here we propose to conduct a field study of the causes, mechanisms and consequences of female competition within the frameworks of sexual and social selection theory. In a group-living primate from Madagascar (red-fronted lemurs, Eulemur rufifrons), related females are regularly evicted from their natal group, and the victims of this intense form of aggression are unable to join or form other groups, presumably resulting in their premature death. By combining long-term demographic with behavioral and physiological data from this species, we will (1) evaluate the relative importance of social selection and sexual selection in shaping competitive regimes to illuminate causes of female competition, (2) characterize social and physiological phenotypes of victims and actors of aggression to address mechanisms of female competition, and (3) contrast patterns of reproductive skew between the sexes to understand its evolutionary consequences. By also contrasting patterns of female competition with male emigration, by examining their potential interdependence, and by exploiting behavioral variation among groups as well as ecological variation among seasons, we will contribute to a refined understanding of an evolutionarily puzzling phenomenon and the interplay between social and sexual selection.