Determination of conspecific alarm constituent and study of learned predator recognition in Aquatic and Terrestrial Environments using Newts.

摘要

The constant threat of predation has forced many prey species to evolve efficient strategies to survive. It has been demonstrated that amphibians elicit an innate anti-predator response to conspecific injury-released alarm cue. Yet the active component of conspecific alarm cues in newts is unknown. Using HPLC techniques to separate the components of newt skin extract (NSE) for two species of newt (Cynops pyrrhogaster and Notophthalmus viridescens) and common behavioural assays, I attempted to identify the location of the active component in newt damage-released alarm cue. The results indicated that there may be more than one active component that elicits an alarm response in NSE. The identity of these active components in NSE remains unknown. Previously it has been thought that amphibians employ only innate predator recognition but it has been shown that they also have the ability to learn a novel predator using olfaction and facilitated by injury-released alarm cue. Until now, the learning of novel predator cues has only been demonstrated by newts in aquatic environments. I tested the ability of N. viridescens to learn unfamiliar predators in both an aquatic and terrestrial environment. I found that red-spotted newts were able to learn novel largemouth bass odour in an aquatic environment. However, in a terrestrial environment, no learning occurred. The lack of learning on land is potentially due to latent inhibition based on previous life stage experiences in a terrestrial environment where the newt was less vulnerable to predation. My study provides new insight into the complexity of conspecific alarm cues in newts and the possible effects of life history on risk allocation and future learning.