Female dispersal in a female-philopatric species, Cebus capucinus

Abstract

[White-faced capuchins ( Cebus capucinus ) reside in multimale–multifemale groups characterized by female philopatry and frequent male dispersal. However, over the years we have observed five females immigrate into our study groups and 23 disappear/emigrate. We examined long-term demographic and behavioural data on three groups of C. capucinus residing in Santa Rosa, Costa Rica, between 1986 and 2007. During this time, 56 females resided in our study groups and as of June 2007, 23 were still present, ten were confirmed/presumed dead and 23 were missing. Here we review the circumstances surrounding the five immigrations and 23 missing females and evaluate three main hypotheses to explain female dispersal in a female philopatric species: inbreeding avoidance, reduction of intragroup feeding competition and infanticide avoidance. The two main predictions of the inbreeding avoidance hypothesis were not supported by our study; male tenure did not exceed female age at first birth and the majority of dispersers were parous females. The reduction in intragroup feeding competition hypothesis received moderate support; dispersing/disappearing females tend to leave during the dry season and they have fewer matrilineal kin than females remaining in their natal group. Our data were most consistent with the infanticide avoidance hypothesis in that females are more likely to disperse/disappear during years with male replacements, a time when infant deaths are also more common. These data provide further evidence of the large impact that the movement and actions of adult male white-faced capuchins have on the lives of females in this species., White-faced capuchins ( Cebus capucinus ) reside in multimale–multifemale groups characterized by female philopatry and frequent male dispersal. However, over the years we have observed five females immigrate into our study groups and 23 disappear/emigrate. We examined long-term demographic and behavioural data on three groups of C. capucinus residing in Santa Rosa, Costa Rica, between 1986 and 2007. During this time, 56 females resided in our study groups and as of June 2007, 23 were still present, ten were confirmed/presumed dead and 23 were missing. Here we review the circumstances surrounding the five immigrations and 23 missing females and evaluate three main hypotheses to explain female dispersal in a female philopatric species: inbreeding avoidance, reduction of intragroup feeding competition and infanticide avoidance. The two main predictions of the inbreeding avoidance hypothesis were not supported by our study; male tenure did not exceed female age at first birth and the majority of dispersers were parous females. The reduction in intragroup feeding competition hypothesis received moderate support; dispersing/disappearing females tend to leave during the dry season and they have fewer matrilineal kin than females remaining in their natal group. Our data were most consistent with the infanticide avoidance hypothesis in that females are more likely to disperse/disappear during years with male replacements, a time when infant deaths are also more common. These data provide further evidence of the large impact that the movement and actions of adult male white-faced capuchins have on the lives of females in this species.]