Different colors reveal different information

How nutritional stress affects the expression of melanin- and structurally based ornamental plumage

Kevin McGraw, Emiko A. Mackillop, James Dale, Mark E. Hauber

Research output: Contribution to journalArticle

241 Citations (Scopus)

Abstract

Avian plumage colors have emerged recently as model systems for investigating the types of information that can be signaled by showy sexual displays in animals. In many species, the brightness of carotenoid-based plumage reflects the health and condition of individuals and is used in mate selection. The information contained in melanin-based and structurally based ornamental colors in birds is less well resolved, however. We subjected male house sparrows Passer domesticus and brown-headed cowbirds Molothrus ater to stressful nutritional conditions during molt to test the hypothesis that melanin- and structurally based plumage colors are nutritionally condition-dependent. We restricted food access for treatment males during randomized 6h periods on 4 days per week, while allowing control birds access to food ad libitum throughout the course of the molt. We found that the size and brightness of the melanin-based throat badges in male house sparrows were not affected by nutritional stress. Similarly, there were no differences between treatment and control male cowbirds in the size or brightness of the melanin-based brown hood. However, the structurally based iridescent plumage of cowbirds was indicative of the nutritional condition of males during molt. Nutritionally stressed cowbirds grew significantly less colorful plumage than did males with access to food ad libitum. These results are consistent with observations in other avian species that different types of plumage color communicate different sets of information. Melanin ornaments are less sensitive to nutritional conditions during molt and instead may reflect the hormonal status and/or competitive ability of males, whereas structural coloration appears to be an accurate signal of health and condition.

Original languageEnglish (US)
Pages (from-to)3747-3755
Number of pages9
JournalJournal of Experimental Biology
Volume205
Issue number23
StatePublished - Dec 2002
Externally publishedYes

Fingerprint

melanin
nutrition information
plumage
Melanins
Color
molt
color
Passer domesticus
molting
Sparrows
Molothrus ater
Food
Birds
food
bird
Aptitude
throat
bird control
Health
competitive ability

Keywords

  • Brown-headed cowbird
  • Condition-dependent
  • House sparrow
  • Molothrus ater
  • Ornamental trait
  • Passer domesticus
  • Plumage

ASJC Scopus subject areas

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

Cite this

Different colors reveal different information : How nutritional stress affects the expression of melanin- and structurally based ornamental plumage. / McGraw, Kevin; Mackillop, Emiko A.; Dale, James; Hauber, Mark E.

In: Journal of Experimental Biology, Vol. 205, No. 23, 12.2002, p. 3747-3755.

Research output: Contribution to journalArticle

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