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.

Many prey species lack innate recognition of their potential predators. Hence, learning is required for them to recognize and respond to predation threats. When wild-caught, these same species may show amazing sophistication in their responses to predator cues. They are able to adjust the intensity of their antipredator responses to a particular predator according to the degree of threat posed by that predator. This ability is therefore acquired through learning. While many studies have shown that prey can learn to respond to predator cues through different learning modes, little is known about what the prey are actually learning. The results presented in this thesis show that learned predator recognition goes beyond the simple labelling of predators as dangerous. Using fathead minnows (Pimephales promelas), woodfrog (Rana sylvatica) tadpoles and boreal chorus frog (Pseudacris maculata) tadpoles, I demonstrated that a one time learning event, either through pairing with alarm cues or through social learning, was enough for prey to learn the level of threat associated with the novel predator cues. I showed that the level of danger associated with the predator cues was determined by the concentration of alarm cues when learning through pairing of alarm cues, or by the intensity of antipredator response displayed by the tutors and by the tutor-to-observer ratio when learning occurred through cultural transmission. Moreover, when subsequently exposed to predator cues, prey adjusted their antipredator responses according to the change in concentration of predator cues between the learning event and the subsequent exposure. Prey displayed stronger antipredator responses when exposed to higher concentrations of predator cues and vice versa. When minnows were provided with conflicting information about the danger level associated with a predator, they displayed a safety strategy and used the most recent information available to respond to predation threats. On a longer time.

This SpringerBrief answers the question on how birds recognize their predators using multidisciplinary approaches and outlines paths of the future research of predator recognition. A special focus is put on the role of key features to discriminate against predators and non-predators. The first part of the book provides a comprehensive review of the mechanisms of predator recognition based on classical ethological studies in untrained birds. The second part introduces a new view on the topic treating theories of cognitive ethology. This approach involves examination of conditioned domestic pigeons and highlights the actual abilities of birds to recognize and categorize.

Throughout their lives, prey organisms must balance the tradeoff between fitness-related activities and the risk of predation. To successfully mediate such tradeoffs, prey must have an accurate method to gauge current predation risk. For many aquatic organisms, the use of chemosensory information has been shown to be a ubiquitous and useful tool in mediating predation risk. The chemical cues to which aquatic organisms respond include the odour of known predators and the odour of a damaged conspecific or known or closely related heterospecific. In fishes, the response to damage-released cues from conspecifics or closely related heterospecifics has been shown to be innate, while the response to distantly related unknown heterospecific cues are likely learned. In a series of laboratory and field studies I examined the role of learning in the ability of fathead minnows to respond to damage-released cues of brook stickleback as an indication of predation risk. My results indicate that minnows from a population without stickleback do not recognize stickleback cues as dangerous. However, following the introduction of stickleback, minnows learn to recognize stickleback cues as dangerous. Further study indicated a low ratio of stickleback to minnows in a given population will decrease the likelihood of learning when compared with a similar sized population containing a higher ratio of stickleback to minnows. I also demonstrated that an increase in habitat complexity decreases the ability of minnows to learn to recognize stickleback cues. Studies have further demonstrated that in the face of predation (as indicated by chemical cues from minnows and stickleback) minnows will decrease their antipredator response when in the presence of a fish shoal, especially a shoal of conspecifics. Finally, an examination of the effects of a minnows length, body condition and breeding status indicate that morphological parameters can play a significant role in the intensity of response to he.

I compared populations of the muricid gastropod Urosalpinx cinerea from its native Atlantic and introduced Pacific ranges, examining its responses to major abiotic and biotic environmental factors. Specifically, I assessed its ability to right itself across a range of winter temperatures (Chapter 1), and its behavioral responses to cues from potential introduced range predators (Chapter 2). These studies represent the first phenotypic comparisons between introduced and native populations of U. cinerea, as well as the first comparisons between U. cinerea living in different parts of the introduced range. Taken together, these studies emphasize the value of combining biogeographic comparisons with experimental approaches to explore the evolutionary and ecological dynamics of biological invasions. Chapter 1: Temperature sensitivity of righting response in Urosalpinx cinerea from the native and introduced ranges. Anticipating the ecological consequences of anthropogenic climate change and biological invasions for marine ecosystems requires understanding how changing climate regimes affect ecologically relevant behaviors in introduced species. I compared the temperature sensitivity of righting response speed, a behavior related to overall movement and important to surviving dislodgment and evading predators, between native and introduced populations of U. cinerea. Such comparisons are essential to detecting whether introduced phenotypes have diverged from native range counterparts and have rarely been performed among marine species. Righting speed of U. cinerea from two native range bays (in Connecticut and Delaware, USA) and three introduced range bays (in Washington and California, USA) was tested under three temperature treatments spanning winter conditions across much of its range (5°C, 10°C, 15°C) and at 20°C, a temperature previously identified as optimal for feeding and reproduction in the native range. Snails took significantly longer to right themselves as temperatures dropped from 20°C to 5°C, with the greatest temperature sensitivity in the interval from 10°C to 5°C. However, there were no geographic differences, with snails from all regions responding similarly; therefore, local environmental conditions are likely to determine U. cinerea activity levels across seasons. Since the interval of greatest temperature sensitivity coincides with winter minimum water temperatures in the introduced range, warmer winters brought on by global climate change could allow U. cinerea to be more active throughout the year, with potential concomitant impacts on native oysters and other prey species. Chapter 2: Detection of predation risk cues in Urosalpinx cinerea from the native and introduced ranges. Determining the factors governing the success of introduced predators is key to predicting and managing their impacts. By exploring how an introduced predator uses cues to detect predation risk from top predators in the introduced range, and by comparing individuals from the native and introduced range, we can gain insight into the roles of predator recognition and naiveté in introductions. This study measured cue recognition in U. cinerea, and examined how snails collected from several populations in the native and introduced ranges responded to chemical cues from two crab predators and injured conspecifics. Both native and introduced range U. cinerea responded to Cancer antennarius and Carcinus maenas kairomones, and to conspecific alarm cues. This is the first report of native range individuals of an introduced species demonstrating a pre-existing ability to recognize chemical cues from an introduced range predator with which they had no prior experience. U. cinerea may have benefitted from similarity between their native community and the resident community in their introduced range, as they were capable of recognizing ostensibly unfamiliar crab predators, possibly by relying on common cues or on generalization from predators U. cinerea evolved with in their native range. The ability to avoid disadvantages of novelty may aid the successful establishment of many introduced species.