Inter-group conflicts involving adult female and male bearded capuchins, Sapajus libidinosus (Primates: Cebidae), in the context of provisioned resources: resource defense or sexual selection?

Abstract

Intergroup conflicts are energetically more costly than intra-group disputes, and thus typically occur in contexts in which the energetic returns are relatively high. In anthropogenic environments, provisioned resources tend to be rich in energy and highly agglomerated. While females are expected to defend provisioned resources, the adult males, in turn, are expected to defend the females. Based on this premise, the present study focused on an urban forest in the city of Goiânia (Goiás, Brazil), which is inhabited by two groups of bearded capuchins. Behavioral data were collected using instantaneous scan sampling and all-events records to document intergroup conflicts and define their context. We used a backward logistic regression and stepwise linear regression to analyze the participation of the individuals in the conflicts. Conflicts were more frequent in the context of provisioning, although the number of neither females nor males involved in the conflict varied significantly between contexts. The females did avoid participating in conflicts involving adult males, however, to minimize the risk of being attacked by them. The adult males participated more in the presence of other adult males, which is partly consistent with the hypothesis of the defense of reproductive partners. The conflicts were not more intense in the context of provisioned resources, which contrasted with expectations. The hierarchical relationship between the two study groups, and the fact that the groups were derived from the same social unit, may have contributed to a reduction in the intensity of the conflicts.