Research Programs

The Rich Lab uses molecular biomarkers and other indirect tools to compare primate physiologies and health outcomes in the face of human-mediated environmental challenges. We collaborate with AZA-accredited zoos and maintain a long-term field project at Itwara Forest Reserve in Uganda. Molecular biomarker development and implementation centers around our facility in Allwine Hall at the University of Nebraska Omaha.

Estrogenic Considerations for Zoo Animal Health

Estrogens control female and male reproductive function and respond broadly to diet and other environmental factors. They mainly operate by activating two receptors: ER⍺ and ERꞵ, which modulate a robust network of genes and proteins. Many environmental compounds can also activate estrogen receptors, including naturally occurring plant chemicals (i.e., phytoestrogens). After it became clear that phytoestrogens compromise fertility among domestic animals, the livestock industry began closely monitoring and controlling their concentration in the manufactured feed.

Zoos carefully control phytoestrogen content in pachyderm diets, too. In vitro, estrogen activation assays revealed that purified phytoestrogens found in alfalfa hay consistently activate Southern White Rhinoceros ERs to a greater degree than Greater One-Horned Rhinoceros ERs. When zoos updated their rhinoceros' dietary protocols to account for this,  breeding programs for the Southern White Rhinoceros rebounded to meet the success rates of the Greater One-Horned Rhinoceros. Endocrine-tailored diets for zoo-based cheetahs and pandas also incorporate this approach. It is currently under investigation for other felids (work led by our neighbors and collaborators at Omaha’s Henry Doorly Zoo). Still, zoo guidelines for primates do not generally consider dietary estrogenicity.

We are working with several different AZA institutions and groups to investigate (1) whether standard zoo-based primate diets contain potential phytoestrogens, (2) whether some primates are more or less sensitive to receptor activation or blocking by those compounds, and (3) how we can use that information to develop practical, endocrine-informed recommendations that optimize primate health. Our lab at UNO uses targeted GC-MS profiling to identify the presence and concentration of known phytoestrogens in different zoo diets, especially commercially manufactured pellets. We also construct phylogenetic models of variation in estrogen receptor genes across primate species using publicly available sequences. Through close, long-term collaboration with the Reproductive Sciences Division at San Diego Zoo Wildlife Center, we develop species-specific receptor assays like those previously designed for the rhinoceros. We are also developing RT-PCR-based methods to monitor in vivo dietary estrogenicity responses.

Comparative Ecophysiology at the Itwara Primate Project

The Itwara Primate Project applies an evolutionary framework to examine the relationship between climate change, plant stress, and comparative primate ecophysiology in a region experiencing severe habitat fragmentation. Under Uganda’s National Forestry and Tree Planting Act of 2003, Central Forest Reserves, including Itwara, are preserved for commercial forestry. Itwara’s rich primate community, comprised of chimpanzees, baboons, black and white colobus, red-tailed monkeys, blue monkeys, and pottos, enables simultaneous observation of diverse, species-specific costs and coping mechanisms arising from shared environmental challenges. That, and the reserve’s small area (87 km2), make it an ideal place to investigate relationships between human behavior, forest edge effects, and primate ecophysiology. 

Environmental stressors such as anthropogenic pollutants, heat stress, wind, and UV irradiation intensify along forest edges, and meanwhile, the forest interior buffers organisms against these challenges. Depending on their typical ranging patterns, primates experience varied edge or buffering effects directly as they cope with the heat and other stressors but also indirectly through the consumption of plants, which often cope with those geographic stress gradients by secreting defensive metabolites. Preliminary data match our expectation that baboons spend more time foraging along Itwara Forest’s edges than chimpanzees do, while the latter spend more time in the forest interior.

We use fecal-derived genetic sampling and spatially-explicit camera trap monitoring to develop more conclusive comparisons of chimpanzee and baboon spatial dynamics in and around the reserve. We are also developing detailed plant-based dietary inventories from the same fecal DNA samples through amplicon sequencing of chloroplast DNA and profiling the spatial dynamics of plant metabolite secretion through GC-MS. Once all of these data help us better understand the eco-spatial dynamics facing chimpanzees and baboons, we will apply RT-PCR-based methods to the same fecal samples to compare biomarkers of health on a molecular scale.

Human Migration, Behavior, and Landscape Modification

Plans in progress. Check back soon!