Kevin J. McGraw

Dr. Kevin J. McGraw

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Research Focus & Metrics

Academic Career Length

23Years (2004-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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28 July 2005 in The Science of Nature
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KMKevin J. McGraw
Kevin J. McGraw
EAE. Adkins-Regan
E. Adkins-Regan
RPR. S. Parker
R. S. Parker

10 October 2005 in Functional Ecology
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Journal Article
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KMKevin J. McGraw
Kevin J. McGraw
RSR. J. Safran
R. J. Safran
Kazumasa WakamatsuKazumasa Wakamatsu
Kazumasa Wakamatsu

1 April 2008 in Pigment Cell & Melanoma Research
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Journal Article
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KMKevin J. McGraw
Kevin J. McGraw

23 December 2005 in Behavioral Ecology and Sociobiology
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KMKevin J. McGraw
Kevin J. McGraw
SCStephanie M. Correa
Stephanie M. Correa
EAElizabeth Adkins-Regan
Elizabeth Adkins-Regan


1 January 2010 in Physiological and Biochemical Zoology
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Journal Article
Closed access
KMKevin J. McGraw
Kevin J. McGraw
MTMatthew B. Toomey
Matthew B. Toomey
Carotenoid pigments produce the bright yellow to red ornamental colors of many animals, especially birds, and must ultimately be derived from the diet. However, they are also valuable for many physiological functions (e.g., antioxidants, immunostimulants, photoprotection, visual tuning, yolk nourishment to embryos), and as a result they are present in numerous internal body tissues (e.g., liver, adipose tissue, retina) whose carotenoid types and amounts are rarely studied in the context of color acquisition. Because male and female animals typically place different priorities on fitness-enhancing activities (e.g., gametic investment in females, sexual attraction in males), carotenoid allocation may track such investment patterns in the two sexes, and we can test for such sex-specific priorities of carotenoids by assessing body-tissue distributions of these pigments. We used high-performance liquid chromatography to identify and quantify carotenoid pigments from the plasma, liver, adipose tissue, and retina as well as the beak and legs of male and female zebra finches (Taeniopygia guttata), a species in which males display sexually attractive, red, carotenoid-based beak coloration and females also display some (albeit a less rich orange) beak color. To our knowledge, this is the first study of the predictors of carotenoid-based leg coloration-another potentially important visual signal-in this species. The same suite of dietary (e.g., lutein, zeaxanthin, beta-cryptoxanthin) and metabolically derived (e.g., dehydrolutein, anhydrolutein) yellow and orange carotenoids was present in plasma, liver, and adipose tissue of both sexes. Retina contained two different metabolites (astaxanthin and galloxanthin) that serve specific functions in association with unique photoreceptor types in the eye. Beaks were enriched with four red ketocarotenoid derivatives in both sexes (alpha-doradexanthin, adonirubin, astaxanthin, and canthaxanthin), while the carotenoid profile of legs was similar to that of plasma/liver/adipose tissue but with the additional presence of canthaxanthin. Sex differences in beak coloration were attributable to different concentrations of all four red ketocarotenoids. Males also had more colorful legs than did females, and this color difference was due to the increased presence of canthaxanthin in males. Males had higher carotenoid concentrations in plasma and retina than did females, but females had higher carotenoid concentrations in liver and adipose tissue than did males. These patterns are consistent with the apparently different life-history strategies employed for carotenoids by adult males and females, with females prioritizing future access to carotenoids (in tissue stores for egg production) and males prioritizing current access (in circulation, for maintaining bright color and/or health).