Summitting the Smokies: Insights from high elevation endemic beetles

Elevation gradients provide a wealth of habitat for a wide variety of organisms. The Great Smoky Mountains are known for their high biodiversity and rates of endemism in arthropods, including leaf litter taxa. Trechus (Coleoptera: Carabidae) is a genus of litter inhabitants with a near global distribution and over 50 Appalachian species. The Smokies hosts 19 of these species, and Clingman’s Dome alone has eight. The diversification of this 3-5 mm flightless beetle through geological time can provide insight into how the litter arthropod community has responded to historical environments, and how they may react to current and future climate change. We identified beetles morphologically and sequenced six genes to reconstruct a phylogeny of Appalachian Trechus. We then analyzed relatedness in conjunction with recreated niche and assessed the correspondence of hypothesized environmental changes in the region with evolution of niche occupancy across the phylogeny.