Date of Graduation

Spring 2025

Degree

Master of Science in Biology

Department

Biology

Committee Chair

Alicia Mathis

Abstract

Environmentally induced stressors can include threats from predators and competitors. Individuals in territorial species, including the subject of this study, Southern Red-backed Salamanders, Plethodon serratus, face ongoing competitive threats, and loss of contests may be more consequential to territory owners (losing a territory) than to intruders (continuing to be without a territory). Therefore, when the threat of increased predation risk is added, residents may respond differently than intruders. Here, I tested the impact of physical stress, residency status and sex on the territorial behavior of Southern Red-backed salamanders. Territorial behavior was assessed through staged contests with same-sized and same-sexed individuals, using a simulated predator attack as the physical stress. The amount of time salamanders displayed the aggressive posture was significantly affected by an interaction among stress treatment, residency status, and sex. Overall, stressed salamanders showed fewer aggressive displays than non-stressed salamanders, but this difference was stronger for intruders, and particularly female intruders, than for residents. Marking behavior (chin taps) was generally more common in non-stressed salamanders, with the strongest effects for female intruders. The stronger response to stress by intruders than residents and the particularly strong effects on female intruders likely reflect a difference in the costs and benefits of territory ownership. For residents the benefit of maintaining ownership of a territory may outweigh the cost of increased predation risk. Female intruders may value gaining a territory more than males, suggesting a high value of territory ownership for females.

Keywords

Plethodon serratus, territoriality, physical stress, residency status, sex differences, high density population

Subject Categories

Biology | Life Sciences

Copyright

© Abigail C. Nagl

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