Samonds, Karen E.
Irwin, Mitchell T.
M.S. (Master of Science)
Department of Biological Sciences
The integration of nutritional ecology into primatology has provided considerable insight into the feeding strategies of primates, and the ecological factors limiting populations - critical knowledge in a world of rapidly changing habitats. The eastern rainforest of Madagascar is home to one of the world’s most diverse primate communities, often hosting over 12 sympatric lemur species; however, the ecological mechanisms by which these species are able to coexist are not well understood. Two species within this community that have been especially understudied are the nocturnal and folivorous Avahi laniger and Lepilemur mustelinus. My research team observed and collected feeding data on A. laniger and L. mustelinus over a 2-month period (October-December 2020) at Tsinjoarivo, Madagascar. I quantified the nutritional chemistry of the foods eaten by these two species and combined these data with data previously collected on four sympatric lemurs (Eulemur fulvus, Eulemur rubriventer, Hapalemur griseus, and Propithecus diadema) to assess their niche separation. I compared foods eaten by each of these species to discern if there was dietary overlap in foods selected and determine if there were interspecific differences in nutritional variables. I also examined and compared the nutritional chemistry of foods and non-foods (foods not eaten by any of these lemurs) to gain insight on the food selection rules guiding these species’ feeding behaviors.A. laniger and L. mustelinus were largely observed resting, and consuming young leaves. L. mustelinus showed more dietary diversity than A. laniger, consuming 22 plant species, encompassing 18 families, and A. laniger consuming 16 plant species, encompassing 12 families. The two species only shared 5 plant species out of 33 plant species collected- one of which was the same species but different parts. There was high dietary diversity in plant species consumed by the six lemur species, and very little overlap – only 55 out of 213 foods tested being shared by at least two lemur species. Overall, both plant secondary metabolites (PSMs) and macronutrients appeared to drive food selection. A. laniger and P. diadema tolerated high levels of tannins in their diet (which bind to available protein), while as L. mustelinus and H. griseus avoided them, confirming previous studies on the influence of PSMs on food selection. Leaves selected by different species depended on diet type and adaptations: the frugivorous Eulemur species selected high-protein leaves, likely to balance their low-protein fruit foods, while two of the folivores (A. laniger and P. diadema) seemed to tolerate low-protein leaves. These findings suggest that A. laniger and P. diadema may have physiological adaptations that allow them to counteract the effects of tannins, and obtain the protein they need. Most foods not fed on by any of the six lemurs contained tannins, and some are known to contain alkaloids. This study is important for understanding niche separation in primate communities, plant-herbivore coevolution and its generation of diversity in ecological communities, bottom-up control of primate populations, and nutrient cycling. It also has implications for conservation, as understanding the resources needed by these species and their divergences in dietary strategies can help develop more effective conservation efforts. The plants fed on by multiple species could be the focus of reforestation efforts and restoration projects to provide these lemurs with the foods needed to meet their nutritional requirements, and ensure their survival.
Gherardi, Chloe Nicole Marie, "Chemical Niche Divergence in Sympatric Lemurs: Understanding Species' Food Selection" (2021). Graduate Research Theses & Dissertations. 7063.
Northern Illinois University
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