Biomarker Strategy for a Comprehensive Survey of "Pure UV" Plumage Reflectance

University Of Wisconsin-Madison, Madison WI

Investigators

Abstract

Color is one of the most striking characteristics of many animals, and color can be used as a means of communication for animals. Animals differ widely in the means they use to convey information, and communicate. Understanding the causes and consequences of these differences can lead to fundamental insights into the nature of communication. Birds and humans both rely on visual communication, but birds can see many more colors, including ultraviolet (UV) colors invisible to humans, and in some cases, most of bird coloration is in the UV. To date, the study of the frequency and distribution of pure UV among birds has been hampered by both technical challenges (time-consuming nature of reflectance measurements) and by a focus on within species variation related to sexual dimorphism and sexual selection, rather than potential differences among species. This project will use the PI''''s recent discovery of a subtle, noncolored, but human-visible, marker associated with, and likely producing, pure UV coloration. This project is risky because at present we do not know how wide spread this marker is, if it always generates pure UV color, or if there are other, yet undiscovered properties of feathers that generate similar pure UV. This mechanism may be restricted to the birds the PI has already examined, or could be wide spread, and if so, would dramatically change our perspective on the importance of pure UV coloration for communication in birds. The PI proposes to examine specimens in major museum collections for this marker, test whether this marker does in fact confer pure UV reflectance in all species where it is found, and then use the large collections in American museums to look at the frequency and distribution of pure UV coloration in all of the birds of the world. Once this survey is completed, the resulting information could transform our understanding of several basic biological processes, including how organisms use structure to generate color, and the importance of enhanced color vision (sensitivity to pure UV) for the evolution of biodiversity and within versus between species communication. This work has many broader impacts. This work is ideal for introducing young scientists to the fields of functional morphology, biophysics, systematics, and biodiversity. One graduate and one undergraduate student will participate in the project. The development of an inexpensive and low-teach biomarker method for evaluating the hidden colors of birds could open up this otherwise technical area of inquiry to developing science programs both domestically and abroad.