A Comparative Analysis of Santa Cruz Island Fox and Island Spotted Skunk Microbiomes

Abstract

Santa Cruz island foxes and island spotted skunks, two mammalian carnivores cohabitating an island environment, exist in a unique relationship where niche overlap has driven interspecific competition but not the displacement of either predator from the island. The factors that allow the coexistence between these island-endemic predators to persist has not been fully explained. This paper seeks to identify the main drivers of variation in the microbiomes of these uniquely coexisting wild populations to understand how phylogenetic and ecological differences between these skunks and foxes may be reflected in microbe presence and diversity in their microbial communities. We characterize the microbial communities of the two species using 16S rDNA sequencing to identify the presence and diversity of microbial taxa within different skunk and fox body sites. We identify host species as the primary driver of variation in microbial diversity and find that the most abundant microbe phyla within both host species are consistent with the core set of mammalian microbes established in previous microbiome research. We additionally find that certain microbiota are differentially abundant between the gut microbiomes of host species. This initial microbiome study on Santa Cruz island foxes and island spotted skunks contributes to a growing understanding of mammalian host microbes as shaped by phylogenetic and ecological influences.