Skip to Main Content
 

Global Search Box

 
 
 
 

Files

File List


MaiaR_dis (final comments 1).pdf (19.62 MB)

ETD Abstract Container

Abstract Header

The Development and Evolution of Iridescent Colors in Birds

Maia Villar de Queiroz, Rafael
http://rave.ohiolink.edu/etdc/view?acc_num=akron1407503755

Abstract Details

2014, Doctor of Philosophy, University of Akron, Integrated Bioscience.
A key question in evolutionary biology is the origin and evolution of morphological innovations. Iridescent colors in feathers are produced by the interaction of light refracting through nanostructurally organized arrays of keratin and melanin-containing organelles (melanosomes), and are responsible for the brightest and most diverse colors found in birds. Such diversity arises from minute changes to nanostructural components, and birds have evolved extensive modifications to the shape and composition (hollowness) of melanosomes, providing a labile template for selection to act. Further, feather colors play a crucial role in intraspecific communication, sexual and social selection, and prezygotic isolation. Thus, this system is ideal for examining how complex morphologies arise ontogenetically and how they affect color diversification. I explored how this nanostructural arrangement emerges developmentally, showing that organization takes place in the final stages of feather growth, potentially through self-assembly. This implies that the fine-tuning color-producing structures can result from changes in the relative concentrations of different components and the timing of feather maturation. Further, quantitative variation to the degree of long-range order is responsible for variation in the degree of glossiness. Gloss was negatively associated with the thickness of the keratin layer, and positively with the continuity of the underlying melanosome layer. As a consequence, a continuum from matte black to iridescent colors can be observed. In African starlings, transitions from the ancestral rod-shaped melanosome to more optically complex morphologies occur irreversibly and towards greater optical complexity. As innovations to melanosome morphology evolve, novel colors can evolve up to forty times faster, as the optical complexity of these structures allows for different aspects of coloration to be modified independently. As a consequence, these innovations also provide opportunities for faster lineage diversification. These changes in color-producing mechanisms also have a stronger association with the evolution of plumage color patterns, but not dichromatism, than some ecological or social aspects of their biology, highlighting the importance of proximate mechanisms in regulation and constraint of the evolution of different color types. Together, these results reinforce the importance of understanding how complex phenotypes are produced to elucidate how they can be selected upon and diversify.
Matthew Shawkey, Dr. (Advisor)
Todd Blackledge, Dr. (Committee Member)
Richard Londraville, Dr. (Committee Member)
Jutta Luettmer-Strathmann, Dr. (Committee Member)
Dustin Rubenstein, Dr. (Committee Member)
146 p.
Biology; Evolution and Development
evolution, phylogenetics, optics, sexual selection, feather

Recommended Citations

Citations

  • Maia Villar de Queiroz, R. (2014). The Development and Evolution of Iridescent Colors in Birds [Doctoral dissertation, University of Akron]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=akron1407503755

    APA Style (7th edition)

  • Maia Villar de Queiroz, Rafael. The Development and Evolution of Iridescent Colors in Birds . 2014. University of Akron, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=akron1407503755.

    MLA Style (8th edition)

  • Maia Villar de Queiroz, Rafael. "The Development and Evolution of Iridescent Colors in Birds ." Doctoral dissertation, University of Akron, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=akron1407503755

    Chicago Manual of Style (17th edition)

akron1407503755
591
© 2014, all rights reserved.
This open access ETD is published by University of Akron and OhioLINK.