Date of Graduation

Spring 2019

Degree

Master of Science in Biology

Department

Biology

Committee Chair

Alicia Mathis

Keywords

Ambystoma, chemical communication, alarm cue, ontogeny, heartrate

Subject Categories

Behavior and Ethology | Ecology and Evolutionary Biology | Terrestrial and Aquatic Ecology

Abstract

Detection of predators early in a predation sequence may allow prey to increase their probability of survival by taking evasive action. For aquatic species in ephemeral ponds visibility is often limited, so predation risk assessment via chemical cues can be useful. Most mole salamanders of the genus Ambystoma breed in vernal ponds, and larvae suffer high mortality rates due in part to high levels of predation. I tested whether larvae can assess predation risk by detecting chemicals (alarm cues) released from the skin of damaged conspecifics, and, if so, what factors influence the response to this alarm cue. Field-caught spotted salamander larvae (Ambystoma maculatum) responded with fright to the chemical cue of damaged conspecifics, but not to control cues. To investigate the ubiquity of this response throughout ontogeny, I conducted further experiments to examine effects of age and experience of cue donors and receivers on alarm responses. In a second experiment, I measured responses of neonate larvae to alarm substance from two different age classes of conspecifics, using heartrate as indicator of fright. The neonate larvae showed increased heartrate (fright) to the cue from older conspecifics, but not the cue from conspecifics from their own age class. My third experiment tested whether larval experience is required for response to the alarm cue. In this experiment, lab-reared individuals did not distinguish between conspecific alarm cues and the control stimuli. My study provides the first evidence for the production of chemical alarm cues by larval salamanders and indicates that alarm responses may vary due across ontogenetic development.

Copyright

© Katlyn M. Gardner

Open Access

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