Sexual Dimorphism and Ecological Correlates in Macaca maura (H.R. Schinz, 1825)

Sexual Dimorphism and Ecological Correlates in Macaca maura (H.R. Schinz, 1825) A variety of causal models beyond sexual selection have been suggested in order to explain degree of body mass dimorphism, among which are body size, niche divergence, energetic requirements (e.g., reproduction) and energetic constraints associated with diet. Whereas in monomorphic species costs of male and female body maintenance are equal, in species with positive body mass dimorphism (pBMD), male costs can outweigh those of females. However, this may not hold true if female reproductive costs, in combination with different degrees of BMD, are considered. In fact, when pBMD is slight, female overall costs usually exceed male costs of body maintenance; when pBMD is moderate, female costs may still outweigh, or else counterbalance, male costs. However when pBMD is strong, male costs generally outweigh overall female costs. In macaque species pBMD is reported as being ‘moderate to strong’ and Macaca maura is no exception. Energetic investments and requirements in BMD species may be investigated by studying sex differences in daily activity budgets and diet composition. Behavioural data were collected on a M. maura (IUCN red list; EN) free ranging social group (n = 31) living in Karaenta (Bantimurung Bulusaraung National Park, South Sulawesi) from September to December 2014 (450 group scans). Sexes differed significantly in daily activities (p = 0.0005) with females spending more time than males foraging and feeding (p = 0.02) and less time resting (p = 0.00007). While sex did not show an overall effect on diet composition (plants/arthropods/ fungi/other), females differed in the higher proportion of arthropods eaten compared to males (p = 0.0001). Preliminary results suggest potential effects of sex on activity budgets and diet composition.