Community processes structuring assembly and disassembly of bat gut-microbial communities across a gradient of habitat degradation

Texas Tech University, Lubbock TX

Investigators

Abstract

Mammal guts are home to communities of microbes that play an important role in the nutrition and health of individual animals. These microbial communities, or microbiomes, are made up of hundreds of species of bacteria, but which species are present, and how common they are, varies from individual to individual animal. This variability is important because abnormal communities can lead to conditions that range from obesity to depression. However, the rules by which microbial communities come together or breakdown are poorly understood. Using wild bats as models, the researchers will investigate how host sociality, diet, genetics, and microbe functions and interactions shape the make-up of digestive microbiomes. The results of this research to understand the rules governing microbiome composition can help advance human and wildlife health. To improve students' understanding of how scientific research is conducted, the team will engage elementary school students from around the country in the project, sharing data live from the field in real time. Students will learn how to analyze and interpret the project data through the researchers' STEM K-12 initiative: The Malaysian Bat Education Adventure. Using an existing Biodiversity module (grades 5-6) and a new module "Microbial Diversity: What's in your bat?" (grades 6-7), students will be introduced to topics of microbial ecology and diversity. The program's success in changing student STEM knowledge, skills and attitude will be evaluated with quantitative methods in a pre- and post- intervention design with control group. The research will determine the relative role of community processes in structuring gut-microbial composition and function in insectivorous bat species co-distributed across a gradient of habitat degradation. The researchers hypothesize that microbiome community assembly and disassembly involve deterministic processes of niche filtering, species interactions, and dispersal. This research will test the hypothesis that changes in host ecology wrought by habitat degradation will alter the relative influence of these processes with consequences for community composition and function. Bats will be studied across a forest modification gradient in Malaysia, and individually-matched samples of gut-microbial composition, metagenome function, dietary composition, host genotype and measures of social interaction obtained for each bat. These data, in conjunction with analyses of co-occurrence, phylogenetic and functional trait patterns, will be used to test structural equation models specified to untangle the processes structuring communities in a causal modeling framework. Evidence of the role of dispersal in structuring microbiomes will derive from comparisons of co-distributed host species that differ in sociality. Interspecific associations will be assessed using co-occurrence network approaches. Functional trait space is developed from genomic inference for each bacterial phylotype within an individual bat's microbiome. Phylogenies are estimated using maximum likelihood and 16S gene alignment among community members. To test the role of diet and host genetics (the host environment) in community processes, the researchers describe diet from feces with the COI DNA barcodes, and quantify host diversity and relatedness through genome fingerprinting. 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.