Environmentally-induced stress is common in the life histories of organisms, and, to a large extent, the organism's response to those stressors determines successful survival and reproduction. Therefore, in order to understand feedbacks between environment and organism performance, it must be determined whether and how organisms adapt their phenotypic responses to commonly encountered stressors such as predators. These responses to stressors may come at both current and future costs to the organisms performance. This project aims to determine whether and how local adaptation of the stress response occurs in populations of wood frogs (Rana sylvatica) that live along a gradient of larval predation risk. Using a common-garden approach coupled with stress hormone manipulation, the project will test for adaptation in two potential mechanisms that would reduce the costs of stress in high-predator ponds: reduction of stress hormone production to predators, and reduction of physiological responsiveness to circulating stress hormones. If the cost of chronically responding to the constant presence of predators is greater than the benefit, then investigators expect that tadpoles from populations in high-predator ponds will exhibit either reduction of their production of stress hormones or reduction in their response to experimentally-elevated stress hormones. The results from this project will contribute to our general understanding of the effects of environmental stress on organisms as well as provide insights into how amphibians in particular are able (or unable) to cope with chronic environmental challenges. In addition, this project will provide opportunities for involving undergraduates in primary research, as well as incorporating public outreach and education to local landowners regarding the amphibians and other organisms their ponds and wetlands support.
