The gut microbiota, defined as the collection of microbes inhabiting the gastrointestinal tract of animals, is critical for their hosts’ functioning. In mammals, resident gut microbes prime the development of their host’s immune system, detoxify plant secondary compounds, synthesize essential vitamins, and contribute to their host’s digestive efficiency. Prior studies conducted across a wide range of mammalian taxa reveal that host phylogenetic relatedness and host diet are strong drivers of gut microbiota structure; however, depending on the host taxa surveyed and the type of habitats and diets represented, one factor may be more influential than the other. Here, we use 16S rRNA gene sequencing surveys to disentangle the effects of host phylogeny and host dietary guild on the gut microbiota of 11 species of herbivores living sympatrically in the Masai Mara National Reserve, Kenya. The study species represented three orders and 5 families (Bovidae, Equidae, Giraffidae, Suidae, Elephantidae), and were classified as either grazers, browsers, or mixed-feeders.
Results/Conclusions
Our results demonstrate that host family and species accounted for 34% of the variation in the gut microbiota while dietary guild explained 12% of the variation. However, within a single host family (Bovidae), host dietary guild and host species explained similar amounts of variation in the gut microbiota (~13%) and within a dietary guild, the gut microbiota was highly species-specific, with host species identity accounting for >30% of the variation. Overall, these findings suggest that host phylogeny may structure the microbiota at broad taxonomic scales, but diet may be more influential in driving the composition among more closely related species.
IMPORTANT NOTE: In the recorded seminar, at the 9:37 time mark (the phylosymbiosis scatterplot slide), the mantel test statistic is incorrectly reported as r=0.25. The correct statistic is r=0.75. The mantel statistic for the second scatterplot (for Bovids) is reported correctly.