Mechanisms of Color Production and Animal Visual Signals

Arizona State University, Scottsdale AZ

Investigators

Abstract

PI: Ronald L. Rutowski Proposal Title: Mechanisms of Color Production and Animal Color Signals Proposal No.: 0316120 Animals produce color signals using both chemical pigments and physical structures. The specific mechanism employed is predicted to have consequences for how they use the signals in behavioral interactions. This three-part project examines these consequences in the Orange Sulphur, a common North American butterfly. In this species, pigments produce the yellow-orange and black markings on the male=s upper wing surfaces while structural modifications found only on the male=s upper wing surfaces produce an iridescent and highly directional ultraviolet (UV) reflection. The first part of the project describes the nature and appearance the UV signal by describing its physical characteristics and then analyzes the spatial relationships between interacting butterflies to see if signal transmission is optimized. The second part examines how much males in nature vary in the structural- and pigment-based components of male coloration and the extent to which this variation leads to variation in male mating success and avoidance of harassment by other males. In the third part, males will be reared under different conditions to see how much the environment affects a male=s coloration and therefore the extent to which a male=s coloration may indicate his condition or quality. These last two parts together test recent suggestions that some mechanisms of color production might provide more information than others about the quality of male signalers for females in mate choice. This project provides rich research and training experiences for students from diverse backgrounds and levels of professional development in the hopes of encouraging and enabling their pursuit of careers in science. The results will be disseminated to a broad audience through the scientific and popular press, web-based materials, and public presentations for non-profit natural history organizations.