Publication Date

2025

Advisor(s) - Committee Chair

T. Keith Philips, Steve Huskey, Carl Dick

Degree Program

Department of Biology

Degree Type

Master of Science

Abstract

Cave beetles are an excellent group to study evolutionary history and speciation by isolation within cave habitats. However, they are underrepresented in such studies, particularly in North America, one of the hotspots of cave biodiversity where beetles account for a significant proportion. The present research addresses this issue by focusing on the Kentucky endemic cave beetle, Neaphaenops tellkampfii, a species hypothesized to comprise four subspecies. Based on allozyme data, previous studies have noted high genetic variation within and high similarity among local populations of this beetle, suggesting complex evolutionary dynamics. In this regard, this study aims to elucidate the evolutionary history of the species while reassessing the validity of the proposed subspecies. For this, specimens were collected from 62 caves within its known range of distribution. Deoxyribonucleic acid (DNA) was extracted, and 1169 bases of the Cytochrome C Oxidase Subunit 1 (CO1) gene were amplified. Bayesian, Maximum Likelihood, and Parsimony phylogenetic trees were constructed, and the genetic structure was visualized with Split tree and Haplotype networks. The beetle showed two distinct mega-populations, separated by the Barren River into southern and northern clades, with genetic differences ranging from 1.7% to 2.7%. High genetic similarity of no more than 0.9% was observed within each of these clades. The subspecies N. t. tellkampfii are proposed as N. tellkampfii (type locality) and include all three northern subspecies. The southern subspecies is raised from the subspecies status, N. t. meridionalis, to species level as N. meridionalis. This study also discovered 26 new caves with populations of both species. The high genetic similarity within the clades indicates the massive connectivity of the caves within the Mississippian Plateau, facilitating dispersal and gene flow. These results have broad application to the speciation of many other cave organisms in this important karst region.

Disciplines

Biology | Ecology and Evolutionary Biology | Entomology | Evolution | Life Sciences

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