Will Aguado
Plant secondary metabolites, nutrients, and physiology in wild Bornean orangutans
My study will examine how a class of Plant Secondary Metabolites (PSMs) called tannins, as well as nutrients guide the feeding behavior of Bornean orangutans (Pongo pygmaeus wurmbii) inhabiting the PSM-rich peat swamp environment of Tuanan, Indonesia. He aims to integrate PSMs into a nutritional ecology framework and to elucidate how PSMs may have influenced the course of primate physiological evolution. Tannins are common, often abundant in plant tissue, and are known to deter some mammalian herbivores by binding to plant protein to create complexes that pass through the digestive tract. Studies on some primate species suggest that tannins act as feeding deterrents, while others show that tannins have no effect, or even promote feeding on certain plants. Both negative and positive effects of tannins on food selection have even been found within a single primate species (e.g., chimpanzees). This research uses orangutans of Tuanan as a primate model for understanding how both nutrients and tannins can impact foraging. By analyzing urinary measures of energy and protein balance in conjunction with food availability, tannin activity, and nutritional intake, we will be able to elucidate the relationships between these factors and shed new light on how primates maintain their health when faced with nutritional shortfalls.
Dominique Raboin
The Adaptive Value of the Juvenile Period: Growth, Hormones, and Energetics in Immature Olive Baboons (Papio anubis) in Different Habitats
The juvenile period is a fundamental component of mammalian life histories, but its length varies considerably across species. Primates are conspicuously unusual in having the longest juvenile periods for their body sizes compared with other mammals. The Ecological Risk Aversion hypothesis (ERA) posits that the extended juvenile period in primates is due to extrinsic constraints on survival, such as predation, feeding competition, and food availability. A rigorous though rarely utilized means of testing the ERA hypothesis is comparative study of juvenile primates of the same species occupying environments that differ in predation risk and food availability. By adopting this framework, this research will more directly address the longstanding debate about the adaptive significance of the extended juvenile period that defines primate life histories. To do so, I aim to answer the following questions (in Kanyawara, in Kibale National Park, Uganda). How do juveniles in two populations (of olive baboons) characterized by divergent ecological conditions vary in: 1) feeding competition; 2) growth trajectories; 3) energetic status and psychosocial stress; and, 4) social relationship quality and social network position?
