Date of Award

January 2012

Degree Type

Open Access Thesis

Degree Name

Master of Science (MS)

Department

Biological Sciences

First Advisor

Paul V. Cupp

Department Affiliation

Biological Sciences

Abstract

The morphology and behavior of most species are influenced by predator-prey interactions. To avoid microhabitats that pose an increased predation risk salamanders may use predator avoidance. Salamanders detect chemical alarm cues via the vomeronasal organ and their avoidance of the chemical cues is based upon the apparent associated risk. The objective of this study was to better understand predator avoidance by means of chemical alarm cues in northern zigzag salamanders, Plethodon dorsalis. Adult salamanders were placed into Petri dishes with a choice between treated substrate (filter paper treated with chemical cues) or untreated substrate (filter paper treated with distilled water). After a period of habituation, the salamander locations within the dishes were recorded every 3 minutes for 60 minutes. The dishes where then rotated 180O and tested for another 60 minutes. To test for the effects of tail autotomy and time on predator avoidance, responses of tail-autotomized salamanders to chemical cues were compared to responses of tail-intact salamanders on days ranging from 1 to 12 following tail autotomy. Tail-intact and tail-autotomized P. dorsalis avoided the chemical cues of injured conspecifics (whole body macerations) and those of eastern garter snakes, Thamnophis sirtalis. Tail autotomy combined with the time since tail autotomy did not influence predator avoidance of P. dorsalis to chemical alarm cues of injured conspecifics or those of T. sirtalis. Also, P. dorsalis did not avoid chemical cues of tail-intact or tail-autotomized ravine salamanders, P. richmondi (a related sympatric species) or whole body macerations of P. richmondi. Plethodon dorsalis was shown to avoid the chemical alarm cues of a rinse from the spotted salamander, Ambystoma maculatum. Chemical cue avoidance of autotomized conspecific tails approached significance in P. dorsalis. The results show no significant difference in the response of male and female salamanders to the chemical cues of P. richmondi or conspecific autotomized tails. Plethodon dorsalis may reduce the possibility of predation by avoiding microhabitats containing chemical alarm cues of injured conspecifics or those of predators. This research indicates that a reduction in the anti-predator arsenal of a salamander does not play an influential role in predator avoidance, and the responses to chemical alarm cues are selective in minimizing the associated tradeoffs of reduced foraging and mating opportunities.

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