The impact of habitat quality on female red colobus monkey (Procolobus rufomitratus) reproduction

This study examines the relationship between habitat quality and reproduction in female red colobus monkeys in Kibale National Park, Uganda. Because energetic constraints impact reproductive function in female primates, this dissertation includes data on feeding ecology, activity budgets, mating behaviors, ketone levels, and reproductive hormone concentrations. This multi-faceted approach tests a model in which habitat quality impacts diet and behaviors, which ultimately effect reproductive success. By including four research groups, two in logged areas and two in old-growth areas, this research adds to our understanding of the reproductive behaviors and physiology of red colobus monkeys as well as a comparative perspective for understanding intraspecific differences for primates living in different quality habitats. Red colobus monkeys in logged areas eat more tree species, smaller amounts of each of these species, and include novel foods in their diet compared to red colobus living in old growth forest. They also spend more time feeding than individuals in old-growth areas. Female red colobus monkeys in logged areas are more constrained in their mating behaviors than females in old growth forests. Specifically, they have lower overall copulation rates and focus mating efforts during conceptive periods; whereas, females in old-growth areas mate more often, including during non-conceptive periods. Females in logged areas also have a shorter duration of maximal tumescence. This pattern supports predictions of the cost-of-sexual-attraction hypothesis, where females in poor quality habitats adjust mating behaviors to maximize the likelihood of conception while minimizing their energetic output. However, this energetic strategy may come at a cost of reducing the ability for females to use nonconceptive sex as a reproductive strategy to confuse paternity, avoid infanticide, and enhance male support. Despite differences in habitat quality, females in logged and old-growth areas do not differ as expected in their reproductive hormone concentrations, ketone levels, or degree of reproductive seasonality. Phenotypic and behavioral plasticity in diet and energy expenditure may allow female red colobus monkeys to maintain reproductive function in lower quality habitats that are stable and protected. The ability to adjust to previously logged habitats that are now protected has important implications for conservation management strategies, such as prioritizing areas for protection, and provides insight into how extant primates, including humans, adjust to environmental change