"Social learning, i.e., learning from others, can be essential for rapidly adapting to changing environments, particularly those involving novel risks. The functional importance of learning from others has been examined across a diversity of contexts and taxa, but the neural mechanisms underlying social learning remain poorly understood. A better understanding of these neural mechanisms could help us attribute differences in social learning propensities across taxa to either evolutionary or experiential variation and provide us with a more complete understanding about the determinants, distribution and impacts of social learning. In this thesis, I explore the behavioural and neural processes underlying learning about novel dangers in the Trinidadian guppy (Poecilia reticulata), using two types of conspecific (social) information: alarm cues, which are chemicals released during tissue damage as part of a predation event, and cues from experienced conspecifics. To gain insight about which brain regions contribute to social learning, I quantified pS6 expression as a measure of neuronal activity in key forebrain areas that are implicated in various forms of learning or social behaviour. In Chapter 2, I demonstrate that guppies learn to associate a novel light stimulus with alarm cue and that learning leads to significant increases in activity in the ventral part of the ventral telencephalon (area Vv; a putative homologue to the lateral septum) as well as in the preoptic area. In Chapter 3, I found that guppies socially learned an aversion to an originally neutral light stimulus via interactions with previously trained conspecific ‘demonstrators.’ However, I did not observe differences in neural activity in response to learning. Taken together, these results show that guppies can learn about novel dangers from both alarm cue and alarmed conspecifics but raise the possibility that forebrain circuits differentially contribute to these forms of social learning. I discuss how cue variability and social context might affect learning rates, and whether some forms of social learning could be mediated by changes in activity in certain neuronal subpopulations. Overall, this thesis underscores the importance of taking a multifaceted approach towards exploring the neural substrates of social learning and lays foundations for exciting future studies into the neural mechanisms of adaptive behaviours"--

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 aquatic species produce chemical alarm cues that serve as a warning to nearby conspecifics. In mixed-species aggregations, individuals may also benefit by “eavesdropping” on the chemical alarm cues of other species that are in the same prey-guild. Rainbow Darters (Etheostoma caeruleum) are benthic fish that co-occur with native Ozark Minnows (Notropis nubilus), recently-introduced Western Mosquitofish (Gambusia affinis), and native Oklahoma Salamanders (Eurycea tyrnerensis), all of whom are vulnerable to the same predators. We tested the responses of darters to the damage-released alarm cues of conspecifics (positive control), minnows, and mosquitofish; alarm cues from Bumblebee Gobies (Brachygobius doriae) served as a negative (allopatric) control. We also tested the response of sympatric and allopatric darters to the damage-released alarm cues of Oklahoma Salamander. Darters exhibited a fright response to conspecific and minnow alarm cues, but not to cues from mosquitofish or gobies. Lack of response to mosquitofish cues could be because they are introduced or because they typically occur higher in the water column than darters. Darters that were sympatric with the salamander exhibited a fright response to the alarm cues of the salamander, while allopatric darters did not. Rainbow Darters can develop responses to the alarm cues of syntopic species (minnows and Oklahoma Salamander) within their prey guild.

Recent studies have shown that juvenile centrarchids undergo significant ontogenetic shifts in habitat use, foraging strategies and perceived predation risk, as well as in the use of conspecific and heterospecific damage-released chemical alarm cues. Microhabitat characteristics, such as habitat complexity and light availability, limit the use of visual cues, which increase perceived risk and can delay the shift to chemical alarm cues. The first experiment explores the behavioural responses of largemouth bass (Micropterus salmoides) between 40 and 65 mm SL to heterospecific or conspecific alarm cues in both high and low light conditions, or complex and open habitats. Individuals were exposed to the same chemical cue under both visually limited and unlimited conditions to study the plasticity of behavioural decisions by an individual. The second study was conducted in the field and used three focal size classes of pumpkinseed sunfish (Lepomis gibbosus) exposed to conspecific and heterospecific alarm cues in varying levels of habitat complexity. The results demonstrate significantly threat-sensitive behavioural decisions. With low habitat complexity or high light availability perceived risk was low and more significantly individuals demonstrated a foraging response. In high habitat complexity and low light availability perceived risk was high and individuals showed a greater anti-predator response. These results confirm that the shift from anti-predator to foraging responses is a threat-sensitive response and individuals are constantly making behavioural decisions based on the perceived risk and reliability of information available to them.

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.

Encyclopedia of Animal Behavior, Second Edition, Four Volume Set the latest update since the 2010 release, builds upon the solid foundation established in the first edition. Updated sections include Host-parasite interactions, Vertebrate social behavior, and the introduction of ‘overview essays’ that boost the book's comprehensive detail. The structure for the work is modified to accommodate a better grouping of subjects. Some chapters have been reshuffled, with section headings combined or modified. Represents a one-stop resource for scientifically reliable information on animal behavior Provides comparative approaches, including the perspective of evolutionary biologists, physiologists, endocrinologists, neuroscientists and psychologists Includes multimedia features in the online version that offer accessible tools to readers looking to deepen their understanding