Doctoral Dissertation Research: The Role of the Gut Microbiome in Digestion and Energy Production in Wild Primates Across a Shifting Nutritional Landscape

Studies of the microbiome have shown that gut microbe communities can affect a host’s ability to harvest energy and store fat. However, the significance of gut microbiome plasticity and its relevance to host survival when faced with environmental fluctuations in nutrient availability remains unclear. This doctoral dissertation research uses evolutionary and ecological approaches to examine gut microbiota changes in wild primates that cope with extreme variability in forest fruit production, resulting in substantial fluctuations in caloric intake and major shifts in the types of foods available for consumption. This study advances knowledge about primate microbiome adaptations, which may also provide comparative data for examining adaptations in the hominin lineage and microbiome function in modern humans. The project facilitates doctoral degree completion for a woman and first-generation student and provide field, laboratory, and bioinformatics training for students from groups underrepresented in STEM research. The project also enhance research capacity at the research location through training workshops and collaboration. Orangutans cope with environmentally-induced variations in diet, such as reductions in caloric intake by up to 48%, and fall short of their energetic requirements for several months out of the year. Because gut microbiota have the potential to be powerful drivers of orangutan energetics during periods of fruit scarcity, this study investigates whether gut microbial community compositions change across marked fluctuations in nutritional intake, and also whether those changes result in increased energy harvest and microbial energy production. More specifically, this project (1) monitors environmental changes in fruit availability; (2) uses observations to estimate food intake and match intake with known nutritional values; (3) identifies gut microbial compositions from fecal samples using Next-Generation DNA sequencing; and (4) approximates microbial energy production by measuring short-chain fatty acid concentrations in fecal samples. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.