Date of Award
5-2024
Document Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Plant and Environmental Science
Committee Chair/Advisor
Dr Michael Caterino
Committee Member
Dr Peter Adler
Committee Member
Dr David Maddison
Committee Member
Dr Robert Baldwin
Abstract
Insects have long been used as tools for understanding the health of the natural world and how changes to climate, landscape, and human interaction have affected the communities those environments support. The Appalachian Mountains, located in eastern North America, is the oldest mountain range on the continent, and during its lifespan it has supported an abundance of microhabitats and endemic species to fill them. Conservationists must balance the need to preserve the diversity that is known and continue to explore the region for new taxa, often with limited budget and expertise. A genus of small carabids, Trechus Clairville, may aid in bridging the gap between these objectives. There are over 50 species in Appalachia, with more to be described. Many are endemic to one mountaintop or range, but they are often sympatric with one another, indicating a complex history. In this study, I assess phylogenetic relationships for Appalachian Trechus, revise taxonomy to reflect these relationships, and weigh the relevance of environmental factors to Trechus distributions.
To resolve relationships of Appalachian Trechus, we sampled across their range, collecting specimens by hand and via litter sifting. Individuals were identified morphologically and sequenced for six genes. To test the monophyly of the Appalachian lineages, we included samples from other global trechine lineages in broad ML and Bayesian analyses. We then used these trees to trace the history of the group. Taxonomy was revised consulting type material to better reflect relatedness among taxa. For modern environmental analysis, abiotic factors were extracted to sampling points in ArcGIS Pro, and a canonical correlation analysis was performed in R.
Phylogenetically, Appalachian Trechus are sisters; Microtrechus and the “T. hydropicus group” are reciprocally monophyletic, largely reflecting a boundary at the Asheville Depression (North Carolina). These groups divided approximately four million years ago, and waves of rapid speciation occurred throughout the Pleistocene. The “T. hydropicus group” is described as its own subgenus – Appatrechus n. subgen.. Seven subspecies are elevated because of lack of species monophyly and cladistic age, and three new species are described – Trechus laurelensis n.sp., T. defoei n.sp., and T. virginicus n.sp. CCA analysis returned several environmental variables, including aspect and elevation, as important for these beetles on all taxonomic levels and road density as a negative correlation for all taxa except one. With these revisions and analyses, Trechus of Appalachia can be better utilized as an ecological model for the region, providing a different perspective complementing established systems.
Recommended Citation
Wooden, Patricia, "Phylogenetics and Biogeography of Appalachian Trechus (Coleoptera: Carabidae)" (2024). All Dissertations. 3565.
https://tigerprints.clemson.edu/all_dissertations/3565
Author ORCID Identifier
0000-0001-5744-2094