DISSERTATION RESEARCH: Mechanisms that maintain behavior in the face of environmental change

University Of Alabama Tuscaloosa, Tuscaloosa AL

Investigators

Abstract

Non-Technical Paragraph: Human activities are altering environments at an alarming rate, and these changes can dramatically affect animals and their behavior. An emerging area of concern is with endocrine disrupting compounds (EDCs), which are synthetic or natural compounds that infiltrate habitats in a variety of ways and wreak havoc on functions of the body that aid in survival and reproduction. Oftentimes, behavior is the first thing to change following EDC exposure, but what does it mean when behavior does not change? Frequently this is interpreted as EDCs not having an impact on the individual, but there are many alternative explanations that might provide a greater understanding of how animals cope with environmental stressors. The goal of this research is to determine if animals that are exposed to EDCs maintain their behavior by altering patterns of hormone production, and whether the measures that animals use to counteract the effects of EDCs might be beneficial or harmful to the animal. This project will include an education program to introduce high school students to the impacts of rapidly changing environments on organisms. It will also include outreach to the community by partnering with a local non-profit organization to create 'fish guides' to inform the public of safe areas to catch fish for consumption. Technical Paragraph: The influx of endocrine disrupting compounds (EDCs) into aquatic systems constitutes a major anthropogenic disturbance that influences both physiology and behavior. Sometimes, however, behavior does not change in response to EDC exposure. We do not currently understand the costs associated with behavioral maintenance in the face of environmental change. This project uses an emerging vertebrate model, mangrove rivulus fish (Kryptolebias marmoratus), to explore how changes in endocrine function promote behavioral maintenance in animals exposed to EDCs and alter the correlation structure among behaviors. Behavioral correlation structures are important indicators of an individual's flexibility and can be used to determine how well they can respond to environmental perturbations, both in the short-term and evolutionarily. The researchers measured behavior and collected hormone samples after exposing individuals of different ages and sexes to a gradient of ecologically relevant concentrations of two major EDCs, ethinyl estradiol and nonylphenol. Behavior analysis indicated that there were no changes in average behaviors following exposure, but the correlation structure among behaviors changed. By assaying hormones, the researchers will determine the extent to which endocrine function impacts singular behaviors and the structure of behavioral correlations following EDC exposure. This approach forwards new perspectives on the interpretation of null results, especially for studies seeking to understand the fitness impacts on individuals persistently exposed to EDCs. It will also provide insights into how physiological systems structure the behavioral phenotype, and perhaps restructure it in response to EDCs in ways that impact individual fitness and opportunities for selection to drive behavioral evolution.