Intellectual merit Elaborate animal signals, like the colorful plumage of birds, are costly to produce and maintain, thus communicating reliable information about the bearer to potential mates or competitors. The sensory systems of receivers can drive the evolution of these signals and shape their form and elaboration. However, relatively little is known about the costs of and constraints on the development and maintenance of sensory systems. In the house finch (Carpodacus mexicanus) and many other bird species, carotenoid pigments are used to create colorful sexually selected displays, and their expression is limited by health and dietary access to carotenoids. Carotenoids also accumulate in the avian retina, protecting the retina and tuning color vision. If the accumulation of retinal carotenoids is condition-dependent, then carotenoid pigments may provide a direct biochemical link between color production and perception of these sexually selected displays. In our work to date, we have found that retinal carotenoid accumulation in the house finch varies considerably in wild birds and, in experimental studies, is positively related to dietary carotenoid access and health status. We request finds to expand this research with the use of microspectrophotometry and behavioral experiments to examine whether increased retinal carotenoid accumulation improves color vision and enhances visually-mediated foraging and mate choice. The coevolution of sensory systems and sexual signals has been identified as an important force driving the divergence of populations and species. However, such studies have focused on how sensory systems, adapted to the local environment, subsequently drive the evolution of signals. Our study is transformative because it examines a direct individual-level biochemical link between sensory tuning and signal expression and represents a new direction for the study of the evolution of animal signals. Broader impacts We will integrate education and outreach into every stage of our project and are committed to providing research opportunities for minority students. In the work completed thus far, we have involved and mentored seven undergraduate students, teaching them a variety of biochemical and behavioral research techniques. Two of these students have used our project as a spring board to develop their own collaborative honors project examining the color preferences of foraging house finches that was independently supported by funds from the Howard Hughes Medical Institute Undergraduate Science Education Program and the Barrett Honors College at ASU. The behavioral studies described in this proposal are particularly well-suited to continued involvement of undergraduate researchers, and we would work to increase the involvement of minority students through the NSF Minority Access to Research Careers program at ASU. We are also eager to share our science with the general public and in the past two years we have each given a number of public scientific presentations (KJM - 10, MBT - 2). Additionally, carotenoids play an important role in human visual health and are thought to prevent age-related macular degeneration. Because of their high levels of retinal carotenoid accumulation, birds have emerged as a model organism for studies of the mechanisms and functions of retinal carotenoid accumulation, and our research in a wild bird will inform and enhance the development and utility of this model system.
|Effective start/end date||6/15/09 → 11/30/11|
- NSF: Directorate for Biological Sciences (BIO): $11,372.00