Effects of Hunger and Predation Risk on Foraging Behavior of Graybelly Salamanders, Eurycea multiplicata

Abstract

We examined the effects of predation and hunger levels on foraging behavior of adult neotenic graybelly salamanders, Eurycea multiplicata griseogaster. Hungry and satiated salamanders were exposed to chemical stimuli from a predatory fish (sculpin, Cottus carolinae) and from two nonpredatory species, golden redhorse fish (Moxostoma erythrurum) and tadpoles of leopard frogs (Rana sphenocephala). Latency to attack prey was lengthened in the presence of chemical stimuli from predators regardless of hunger levels, but hungry salamanders had shorter latency times than satiated salamanders. There was no interaction between hunger and threat levels. In addition, salamanders distinguished between chemical stimuli from predatory (sculpin) and nonpredatory (redhorse) fishes; responses to redhorse and tadpole stimuli were not different. Handling times were not affected by either predator treatment or hunger level. In summary, graybelly salamanders can (1) recognize sculpin predators based solely on chemical cues, (2) distinguish between chemical stimuli from predatory and nonpredatory fish, and (3) adjust their foraging behavior according to both hunger and predation risk.