A fundamental challenge of modern Zoology is to understand why, in some cases, large numbers of similar-appearing animal species have formed, and continue to coexist, in relatively limited geographical areas. This study will examine the role of communication in facilitating species boundaries in communities of Anolis lizards. Male Anolis lizards utilize a visual communication signal that consists of the display of a colorful throat fan called the dewlap. Each species has a different color and/or pattern on its dewlap that helps to maintain species diversity by allowing lizards to easily detect, recognize and mate with members of their own species, and avoid interbreeding and unnecessary competition with other similar species. The dewlap?s effectiveness depends strongly on light conditions in each habitat, and on the neural responses of the Anolis visual system. This study will focus on lizard communities on the islands of Jamaica, Hispaniola and Puerto Rico. It will employ techniques from physics, optical engineering, neuroscience, behavioral biology, anatomy, and computer modeling to learn how lizard visual systems detect and discriminate between the colors and patterns found on the dewlaps of different species, and how differences in habitat light influence these capabilities. This project includes a strong educational outreach component. High school, undergraduate and graduate students will actively participate in all aspects of the research and a special effort will be made to include groups underrepresented in sciences. Findings will be communicated to the public via popular articles, public presentations, and web-based modules that allow interested individuals to explore the interactions between the physical properties of light, visual physiology, and ecological conditions. By explaining the role of effective communication in the maintenance of reproductive boundaries between species, the project will provide information that is critical for conservation efforts aimed at preserving biological diversity through habitat preservation and reconstruction.