Variation in the Antipredator Responses of Three Sympatric Plethodontid Salamanders to Predator-diet Cues

Organisms may reduce the risk of predation by responding to chemical cues from predators. Recent research shows that many species vary their antipredator response depending on the diet of the predator. We examined the responses of three plethodontid species of salamander (Plethodon cinereus,Eurycea bislineata, and Desmognathus ochrophaeus) to chemical cues from a shared snake predator (Thamnophis sirtalis). At the time of the study, Eurycea bislineata showed overlap in habitat with Plethodon cinereus and Desmognathus ochrophaeus, but Plethodon cinereus and Desmognathus ochrophaeus showed no overlap with one another. Each salamander species was presented with chemical cues from snakes fed Desmognathus ochrophaeus (TSDo), Eurycea bislineata (TSEb), and Plethodon cinereus (TSPc). Plethodon cinereus avoided both TSPc and TSEb, whereas Eurycea bislineata avoided only TSEb. Conversely, Desmognathus ochrophaeus did not avoid any cues from the predator, regardless of the diet of the snake. When we analyzed activity data, we discovered that Plethodon cinereus showed higher activity levels when exposed to TSPc than to the other cues. Individual Eurycea bislineata did not vary their activity to the three treatments. Lastly, Desmognathus ochrophaeus, which did not avoid any of the cues from the predator, were more active in response to TSDo and TSEb than to TSPc. These results show that phylogenetically related prey species may employ a variety of antipredator behaviors and suggest that discrimination of predator diet-cues may be linked to the degree of microhabitat overlap among the different prey species at the time of our study. Our study also highlights the importance of using multiple response variables when examining antipredator behavior.