© 1992 International Society for Behavioral Ecology
research-article |
Resource distribution, density, and determinants of mate access in puku
Large Animal Research Group, Department of Zoology Downing Street , Cambridge CB2 3EJ, UK
ABSTRACT
The puku is a dimorphic, polygynous, grazing African antelope that lives in patchy alluvial habitats in central Africa. The use of resources and distribution of females was investigated as the key to understanding male social organization. During the dry months, when most mating occurred, females selected the swale vegetation communities close to exposed oxbow lagoons. These communities were unevenly distributed, and female density was positively correlated with mean patch size. Territorial males selected communities similar to females during the breeding season. Differences in selection ratios suggested that territorial males excluded bachelor males from favored communities during the breeding season. Although the operational sex ratio did not differ between good- and poor-quality habitats, differences in the overall sex ratio showed that bachelor males frequented only the areas with high female densities. Indeed, analysis of the costs and benefits of territoriality suggested that intermale competition was greater in the good-quality habitats and that males settled according to the distribution of the resources that determined female densities. However, male mate access was simultaneously and independently related to both territory quality and male phenotype. Male puku have a darkened neckpatch, the intensity of which partially determines mate access.