Acute physiological response by the plethodontid salamander Eurycea cirrigera (Southern Two-lined Salamander) to predation stress from alarm chemicals and predator kairomones

Plethodontid salamanders may reduce predation risk via behavioral responses to predator kairomones and alarm chemicals from injured salamanders. However, it not known whether such predator cues prompt acute physiological responses, which may enhance arousal and the physical ability to escape from a predator. I examined whether predator chemical cues elicit an acute cardiac response in Southern Two-lined Salamanders, Eurycea cirrigera (Green, 1830). I compared heart rates before and after exposure to the odor of large predatory Red Salamanders, Pseudotriton ruber (Latreille, 1801) and exposure to alarm chemicals from homogenized skin of conspecifics. For two controls, I compared heart rates before and after exposure to the odor of live conspecifics and the odor of large non-predatory Mississippi Slimy Salamanders, Plethodon mississippi Highton, 1989. In comparison to resting values, heart rates significantly increased in response to predator kairomones (mean rate increased 10.9% after 2 min and 12.7% after 5 min) and alarm chemicals from conspecifics (mean rate increased 12.0% after 2 min and 14.5% after 5 min). In contrast, heart rates after exposure to each control odor did not significantly differ from resting values. Results demonstrate an acute cardiac response to chemical cues indicative of either a predator or a predation event.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author