Introduction to the Symposium: Stress Phenotype: Linking Molecular, Cellular, and Physiological Stress Responses to Fitness

Although most organisms respond to environmental and social stressors by initiating a stress response that is expected to increase fitness, we currently lack information about how the stress response is integrated across levels of biological organization. Organismal biologists and physiological ecologists have tended to focus on questions related to how the glucocorticoid stress response varies across ecological contexts and is related to fitness, whereas, molecular and cellular biologists have typically investigated the fundamental underlying mechanisms. However, it is becoming increasingly clear that a comprehensive understanding of the evolution of the stress response will require integrative studies that span levels of analyses. This information will be critical for predicting how selection will influence the expression of this complex phenotype at the organismal level, as well as how the integration of the underlying mechanisms will influence the evolutionary response to selection. As diverse organisms are expected to experience rising stress exposure in the face of anthropogenic disturbance and climate change, this information is becoming increasingly urgent. The overarching goals of this symposium were to bring together researchers that study the stress response across levels of organization in diverse organisms to identify important gaps in knowledge and novel research approaches that could be used to advance the field.