Date of Award

2024

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Biology

First Advisor

Dr. Carl D Anthony

Abstract

Following the retreat of glaciers in North America, a wide diversity of organisms rapidly migrated into previously uninhabited regions, including animals with limited dispersal abilities such as amphibians. I wanted to better understand the strategies that salamanders use to aid in their dispersal abilities and to understand if patterns of post-glacial range expansion affect phenotypic traits such as anti-predator strategies. In this study, I used existing phylogeographic evidence of clade membership as a framework to examine whether red-backed salamanders (Plethodon cinereus) differed in tail autotomy behavior at the range edge versus the range core, and across the geographic range of two clades; one of limited range (the Ohio Clade) and one that has dispersed north along the Atlantic coast into Canada, westward, and south into Michigan and Indiana (the Northern Clade). I hypothesized that salamanders belonging to the Northern Clade and salamanders belonging to range-edge groups would exhibit high tail autotomy frequencies and a greater degree of antipredator postautotomy characteristics. I conducted lab experiments and used museum specimens to examine tail autotomy frequencies and other tail autotomy characteristics, including latency to autotomize under predation pressure, duration of tail movement following autotomy, postautotomy tail movement undulations, and tail regrowth. In my lab experiments, I found significantly higher tail autotomy frequencies within range-core populations and significantly greater postautotomy tail movement duration in my sampled populations from the Northern Clade. Further, I found significantly greater frequencies of autotomy in the Northern Clade in my museum specimen analysis. Therefore, I conclude that Plethodon cinereus exhibits geographic variation in tail autotomy frequencies, although the observed patterns of tail autotomy in this study did not align with my initial hypotheses and instead appear to be influenced by several other unidentified variables.

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