An experimental test of the contributions and condition dependence of microstructure and carotenoids in yellow plumage coloration

Matthew D. Shawkey, Geoffrey E. Hill, Kevin McGraw, Wendy R. Hood, Kristal Huggins

Research output: Contribution to journalArticle

60 Citations (Scopus)

Abstract

A combination of structural and pigmentary components is responsible for many of the colour displays of animals. Despite the ubiquity of this type of coloration, neither the relative contribution of structures and pigments to variation in such colour displays nor the relative effects of extrinsic factors on the structural and pigment-based components of such colour has been determined. Understanding the sources of colour variation is important because structures and pigments may convey different information to conspecifics. In an experiment on captive American goldfinches Carduelis tristis, we manipulated two parameters, carotenoid availability and food availability, known to affect the expression of carotenoid pigments in a full-factorial design. Yellow feathers from these birds were then analysed in two ways. First, we used full-spectrum spectrometry and high-performance liquid chromatography to examine the extent to which variation in white structural colour and total carotenoid content was associated with variation in colour properties of feathers. The carotenoid content of yellow feathers predicted two colour parameters (principal component 1 - representing high values of ultraviolet and yellow chroma and low values of violet-blue chroma - and hue). Two different colour parameters (violet-blue and yellow chroma) from white de-pigmented feathers, as well as carotenoid content, predicted reflectance measurements from yellow feathers. Second, we determined the relative effects of our experimental manipulations on white structural colour and yellow colour. Carotenoid availability directly affected yellow colour, while food availability affected it only in combination with carotenoid availability. None of our manipulations had significant effects on the expression of white structural colour. Our results suggest that the contribution of microstructures to variation in the expression of yellow coloration is less than the contribution of carotenoid content, and that carotenoid deposition is more dependent on extrinsic variability than is the production of white structural colour.

Original languageEnglish (US)
Pages (from-to)2985-2991
Number of pages7
JournalProceedings of the Royal Society B: Biological Sciences
Volume273
Issue number1604
DOIs
StatePublished - Dec 7 2006

Fingerprint

plumage
Carotenoids
carotenoid
microstructure
carotenoids
Color
Microstructure
color
Feathers
feather
testing
feathers
Pigments
Availability
pigment
Viola
pigments
food availability
test
Food

Keywords

  • American goldfinch
  • Carduelis tristis
  • Carotenoid pigmentation
  • Diet
  • Honest signalling
  • Sexual selection

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Agricultural and Biological Sciences (miscellaneous)

Cite this

An experimental test of the contributions and condition dependence of microstructure and carotenoids in yellow plumage coloration. / Shawkey, Matthew D.; Hill, Geoffrey E.; McGraw, Kevin; Hood, Wendy R.; Huggins, Kristal.

In: Proceedings of the Royal Society B: Biological Sciences, Vol. 273, No. 1604, 07.12.2006, p. 2985-2991.

Research output: Contribution to journalArticle

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