Meeting Abstract
Rapid, novel changes to an organism’s environment due to invasive species are a global threat to biodiversity. Behavioral shifts are often the first phenotypic response to such changes, particularly when the invasive species poses a predatory threat. The high level of plasticity inherent to most behavior may potentially permit population survival until adaptive changes can occur, and the initial behavioral plasticity itself may even facilitate adaptation. Thus, in order to fully understand how behavioral responses are shaped by novel environments created by invasive predators, it is important to consider both the behavioral responses and the degree of plasticity of that behavior. Northern pike, Esox lucius, is an invasive species in Southcentral Alaska, where it constitutes a novel, intense predatory threat to threespine stickleback, Gasterosteus aculeatus. In this experiment, we asked how antipredator behavior differs among stickleback from pike-invaded and pike-free populations. We quantified stickleback behavior after a simulated attack when placed in one of four chemical cue conditions, thus creating environments differing in the degree of threat (e.g. control vs alarm/predator cues) and specificity of threat (general conspecific alarm cue vs specific predator cue). Populations differed in whether they had experienced the cues associated with the invasive predator within their recent evolutionary history. We show population differences in general antipredator behavior to a simulated attack (differences among individuals in the control condition), as well as population differences in behavioral plasticity, with population-specific responses to chemical cue treatments. We discuss these results here in a broader evolutionary context.
