University of Notre Dame

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The Diet, Mycobiome, and Bacteriome of Long-tailed Macaques (Macaca fascicularis) Have Context Specific Responses to Anthropogenic Environmental Factors

posted on 2023-07-17, 00:00 authored by Benjamin Gombash

Human expansion will inevitably result in more human/wildlife interaction. Some wildlife species, such as macaques, are able to adapt to anthropogenic environments and coexist in them with humans. This is likely due to the fact that macaques are dietary generalists that naturally exploit variable habitats and can utilize anthropogenic food resources. This dissertation is focused on how macaques and their internal microbial communities respond to varying levels and kinds of anthropogenic influence on their diets and external environments. The goal of this dissertation is to use macaques, which are widely distributed and inhabit a range of anthropogenic environments, to highlight the complex set of interactions that take place between a wildlife species, its external environment, and the members of its internal microbial communities, particularly the mycobiome and bacteriome. I find that the diets of macaques respond to different kinds of anthropogenic food resources in different and contrasting ways on the islands of Singapore and Bali, Indonesia. Macaques in Bali seem to narrow their diets when they are heavily provisioned, although access to provisioned foods is not equal among group members. Macaques in Singapore, however, broaden their diets as they have greater access to anthropogenic resources through urban landscape. I also note that there are demonstrable interactions between macaque diets and their mycobiome, with increasing diet diversity resulting in increased mycobiome diversity. The pattern of interactions varies between the two islands despite a major overlap in fungal and dietary taxa involved. Furthermore, I identify that the variation in those interactions may relate to differences in the physical and anthropogenic environment which have direct and indirect effects on the mycobiome, with anthropogenic environmental factors likely using the diet as an intermediary. Finally, I conducted a meta-analysis of multiple macaque bacteriome studies to look at the relative effects that phylogeny, anthropogenic influences on the diet, and anthropogenic alterations to the landscape have in shaping the bacteriome, looking specifically at alpha diversity and composition. I found that each factor plays a significant role, but that the diet and landscape each play a greater role than phylogeny. Furthermore, it is possible that some of the variation that is explained by the diet and landscape is related to Plasmodium infection, which can create distinctive bacterial communities in macaques. In summary, my dissertation highlights the complex set of interactions between a host organism, its diet, the external environment, and its internal microbial communities.


Date Modified


Defense Date


CIP Code

  • 26.0101

Research Director(s)

Hope Hollocher


  • Doctor of Philosophy

Degree Level

  • Doctoral Dissertation

Alternate Identifier


OCLC Number


Program Name

  • Biological Sciences

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