Predator Avoidance in Lab-Reared Juvenile Rough-Skinned Newts, Taricha granulosa

Abstract

Predator avoidance strategies are often viewed in the context of innate or learned, yet a true test of this hypothesis requires animals that are completely nao ¨ve to potential predators. We examined the predator avoidance behavior of juvenile Rough-skinned Newts (Taricha granulosa) that had been reared in captivity since being deposited as eggs and had never been exposed to predators or predator stimuli. In contrast to a previous study on adult newts, juveniles avoided a broader range of chemical stimuli from potential predators, including alarm cues from damaged conspecifics and stimuli from 2 Common Gartersnakes (Thamnophis sirtalis) that had recently consumed newts. These results suggest that predator avoidance in Taricha granulosa is innate. Unlike adult newts, the avoidance of a wider range of stimuli by juvenile newts is likely an effective strategy at reducing predation risk given their small size and lower tetrodotoxin concentrations (compared to adults), both of which render them vulnerable to predation by gartersnakes.