TY - JOUR
T1 - Carotenoid-based plumage coloration reflects feather corticosterone levels in male house finches (Haemorhous mexicanus)
AU - Lendvai, Á Z.
AU - Giraudeau, M.
AU - Németh, J.
AU - Bakó, V.
AU - McGraw, Kevin
N1 - Funding Information:
Acknowledgments ÁZL and JN were supported by the Hungarian Research Fund grants (OTKA PD76862 and K75965) and ÁZL by the Bolyai fellowship of the Hungarian Academy of Sciences and by the Eötvös State Grant by the Hungarian Scholarship Board. During the preparation of the manuscript, ÁZL was supported by an NSF grant (1145625) to Frances Bonier and Ignacio T Moore. KJM was supported by a National Science Foundation grant (IOS-0923694). We thank anonymous reviewers and the associate editor who provided helpful and constructive comments on the manuscript.
PY - 2013/11
Y1 - 2013/11
N2 - Indicator models of sexual selection predict that exaggerated traits communicate information about sender condition or quality to conspecific receivers. Environmental challenges have often been considered as one such condition that could be encoded in an ornamental trait, and there is now extensive evidence showing how different stressors (e.g., nutritional, parasitological, and environmental) impact sexual signal elaboration. One of the primary means of assessing stress is by quantifying glucocorticoid (corticosterone or cortisol (CORT)) levels. For many ornaments, CORT impairs trait expression; however, the evidence is limited and mixed for one of the classic honest signals in animals, ornamental carotenoid coloration. In a model species for studies of carotenoid ornamentation (the house finch, Haemorhous mexicanus), we examined the relationship between male plumage redness and feather CORT levels, which serve as an integrated measure of hormone concentration during feather growth. We measured CORT in both tail (melanin-containing) and breast (carotenoid-containing) feathers and found that CORT levels were not different between body regions, but they were negatively correlated with plumage hue, with redder birds having more CORT in feathers. Despite opposing traditional views on stress and ornamentation, our results actually corroborate three other studies showing positive relationships between carotenoid coloration and CORT levels. Though the molecular mechanisms underlying such a relationship are still unclear, our results suggest that CORT should not be considered as a simple indicator of individual quality but rather as a mediator of complex allocation decisions or signals of metabolic activity that could link up with more elaborate expression of ornamental traits.
AB - Indicator models of sexual selection predict that exaggerated traits communicate information about sender condition or quality to conspecific receivers. Environmental challenges have often been considered as one such condition that could be encoded in an ornamental trait, and there is now extensive evidence showing how different stressors (e.g., nutritional, parasitological, and environmental) impact sexual signal elaboration. One of the primary means of assessing stress is by quantifying glucocorticoid (corticosterone or cortisol (CORT)) levels. For many ornaments, CORT impairs trait expression; however, the evidence is limited and mixed for one of the classic honest signals in animals, ornamental carotenoid coloration. In a model species for studies of carotenoid ornamentation (the house finch, Haemorhous mexicanus), we examined the relationship between male plumage redness and feather CORT levels, which serve as an integrated measure of hormone concentration during feather growth. We measured CORT in both tail (melanin-containing) and breast (carotenoid-containing) feathers and found that CORT levels were not different between body regions, but they were negatively correlated with plumage hue, with redder birds having more CORT in feathers. Despite opposing traditional views on stress and ornamentation, our results actually corroborate three other studies showing positive relationships between carotenoid coloration and CORT levels. Though the molecular mechanisms underlying such a relationship are still unclear, our results suggest that CORT should not be considered as a simple indicator of individual quality but rather as a mediator of complex allocation decisions or signals of metabolic activity that could link up with more elaborate expression of ornamental traits.
KW - Honest signaling
KW - Plumage ornamentation
KW - Sexual selection
KW - Stress hormones
KW - Stress response
UR - http://www.scopus.com/inward/record.url?scp=84885918659&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84885918659&partnerID=8YFLogxK
U2 - 10.1007/s00265-013-1591-9
DO - 10.1007/s00265-013-1591-9
M3 - Article
AN - SCOPUS:84885918659
VL - 67
SP - 1817
EP - 1824
JO - Behavioral Ecology and Sociobiology
JF - Behavioral Ecology and Sociobiology
SN - 0340-5443
IS - 11
ER -