Clinical Assistant Professor Erin Morrison, in collaboration with Ahva Potticary and Alexander Badyaev from University of Arizona's Department of Ecology and Evolutionary Biology, has published a study investigating the adaptive associations between feather structure and carotenoid compounds in birds. Carotenoids are compounds that produce red, yellow, and orange pigment. Different combinations of carotenoids and variations in the concentrations of these compounds deposited in bird feathers produce different plumage colors. Birds, however, cannot produce carotenoids themselves. They have to initially acquire them from their diet, but once consumed many species of birds can transform them into different compounds via pathways of enzymatic reactions. In this study, Morrison and her collaborators examined how feather structure in house finches (Haemorhous mexicanus) adapts to the deposition of unfamiliar carotenoid compounds acquired from new diet sources during rapid range expansion in western North America.
The study found that incorporating novel carotenoids initially induces modifications to feather structure, but also determined that these changes are gradually lost in older populations as the compounds became integrated into feather development. The results of the study shed light on the mechanisms that underlie the persistence of adaptations in new environments.