在北太平洋地區(qū)生活著一種黑色海鳥——小海雀,，其雄鳥頭上長有羽冠。一項新研究表明,，這種羽冠的尺寸是雄小海雀生存能力大小的“特征標(biāo)志”,，羽冠越大的雄小海雀越容易找到“對象”。
美國阿拉斯加大學(xué)費爾班克斯分校的赫克·道格拉斯等人在《比較生理學(xué)Ｂ》（Journal of Comparative Physiology B）上發(fā)表論文說,，雌小海雀喜歡羽冠大的雄小海雀，但科學(xué)家一直不清楚其中的原因,。他們于是在2002年從美國阿留申群島捕捉了一些小海雀進(jìn)行研究,，結(jié)果發(fā)現(xiàn)，羽冠越大的雄小海雀,，其體內(nèi)的壓力激素——皮質(zhì)醇的水平越低,。
道格拉斯說，雄性體內(nèi)的壓力激素越少,，越容易適應(yīng)外部環(huán)境,，羽冠大的雄小海雀在尋找食物、與其他雄鳥爭奪筑巢地點以及幫助孵化和培育后代方面都占有優(yōu)勢,。
研究人員因此推斷,，羽冠是雄小海雀用來贏取雌性“芳心”的“外在特征標(biāo)志”，而不只是好看的“裝飾物”。（生物谷Bioon.com）
生物谷推薦原始出處：
Journal of Comparative Physiology B,，doi:10.1007/s00360-008-0312-6,，Hector D. Douglas III，Alexander S. Kitaysky
Size of ornament is negatively correlated with baseline corticosterone in males of a socially monogamous colonial seabird
Hector D. Douglas III1, 2 , Alexander S. Kitaysky3, Evgenia V. Kitaiskaia3, Aidan Maccormick4 and Anke Kelly5, 6
(1)Institute of Marine Science, University of Alaska Fairbanks, Fairbanks, AK 99775, USA
(2)Biology Department, Kuskokwim Campus, CRCD, University of Alaska Fairbanks, Bethel, AK 99559, USA
(3)Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK 99775, USA
(4)Division of Environmental and Evolutionary Biology, Institute of Biomedical and Life Sciences, Graham Kerr Building, University of Glasgow, Glasgow, G12 8QQ, UK
(5)Department of Animal Physiology, University of Bayreuth, 95440 Bayreuth, Germany
(6)Biology Department, Brandeis University, Waltham, MA 02454, USA
The Goymann–Wingfield model predicts that glucocorticoid levels in social animals reflect the costs of acquiring and maintaining social status. The crested auklet is one of the few avian colonial species where a mutual ornament in males and females is used in both sexual and aggressive displays. Previous studies of the crested auklet support the notion that the crest ornament is a badge of status in this species. Here, we examined the relationship between the crest ornament size and the adrenocortical function in breeding crested auklets. Crest length was negatively correlated with corticosterone at baseline in males, but not in females. Baseline corticosterone in females (but not in males) was negatively correlated with body condition index. Although male and female crested auklets are monomorphic in their ornamental traits, our results suggest that the socially mediated physiological costs associated with status signaling may differ between the sexes.
