Males of many species possess extravagant, brightly colored structures that are costly to produce and that increase their likelihood of being seen and eaten by predators. One of the great problems of evolutionary biology is understanding why females select for such extravagant traits in males. The "sensory bias hypothesis" states that female mating preferences are by-products of natural selection on the sensory system. Under this hypothesis, strong natural selection on animals to find food, avoid predators, and find proper habitats results in indirect selection on mating preferences. The fundamental assumption of this hypothesis is that the genes (and neurological pathways) that affect foraging preferences also affect mating preferences. This project will determine the extent to which different behaviors that share a common sensory system can evolve independently. The objective of the study will be to determine if behaviors share a common sensory system and/or does variation in the sensory system lead to variation in behavior. To address these questions, large amounts of phenotypic variation in visual properties will be generated and multiple aspects of behavior will be measured using the bluefin killifish, Lucania goodei, a species previously demonstrated to have large amounts of variation in visual properties both within and between populations. Broader Impacts: The study will provide the graduate student and several undergraduates experience with a variety of techniques drawn from many disciplines. This project involves the collaboration of evolutionary biologists and molecular biologists/vision physiologists that will help build connections between the evolutionary biology group within the Biological Science Department and other groups, particularly the university-wide Program in Neuroscience. The project should demonstrate that studying natural variation in vision physiology is a worthwhile endeavor, while developing further insights into the evolution of vision physiology.