Date of Award

2023

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Biology

First Advisor

Dr. Carl Anthony

Abstract

Lineages that have undergone genetic divergence and subsequently experience secondary contact present fascinating situations related to the potential for reproductive isolation. Within species hybrid zones provide unique opportunities to test the strength of reproductive barriers through behavioral experiments when genetic relatedness between groups is established. Among the complex interactions that operate to maintain species boundaries, mate recognition and mate choice are two behaviors that serve to promote evolutionary independence across diverse taxonomic lineages. I explored mate recognition in genetically distinct populations of the Eastern Red-backed Salamander, Plethodon cinereus, a small, abundant, terrestrial salamander with a widespread distribution throughout northeastern United States and in southeastern Canada. Earlier studies identified distinct mitochondrial and nuclear clades in northern Ohio, despite some populations of different clades existing in close geographic proximity. To investigate whether female P. cinereus showed a preference for male odors based on clade membership, individuals of two clades were collected and mate recognition trials were performed in the laboratory. One experiment tested the level of interest of females of both clades by quantifying the number of nose taps directed at male odors and a second experiment assessed association by females with male odor via time in proximity to odors. Females did not discriminate between male odors of either cluster based on number of nose taps and the results of the association experiment yielded mixed results. The results of these behavioral experiments corroborate recent studies suggesting that the sex-specific pheromones of P. cinereus in the two clades studied are not yet different enough to result in reproductive isolation between the two genetic lineages. Other explanations for female response to male odors include avoidance behavior and asymmetric mate recognition, among other possibilities. I compare my results with similar studies on mate recognition and discuss future research directions concerning this ecologically valuable salamander species.

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