Date of Last Revision

2023-05-02 13:44:38



Date of Expected Graduation

Spring 2015


Sexual selection favoring the most attractive peafowl is very well understood, but the answer to what drives the variation in peacock feather coloration remains a mystery. The goal of this experiment is to determine the precise physical mechanism used by peafowl to generate such elaborate color variations in the eyespots of their tail feathers among males within the species. Barbs from eyespots of Pavo cristatus were embedded in an epoxy resin, sectioned on a microtome, and TEM images of the nanostructure within each barbule were analyzed. Results indicate that melanosome diameter is a significant positive predictor of iridescence and that as melanosome diameter increases and spacing decreases, brightness will increase. Variation in melanosome size does not predict physiological superiority among peafowl, but because melanin production is established genetically, females choosing to mate with more iridescent males may receive an additional benefit of a higher quality mate.

Research Sponsor

Dr. Matthew Shawkey

First Reader

Dr. Hazel Barton

Second Reader

Dr. Stephen Weeks



To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.