In vertebrates, the endocrine system translates environmental changes into physiological responses on which natural selection can act to regulate individual fitness and, ultimately, population dynamics. Corticosterone (CORT) and dehydroepiandrosterone (DHEA) are important regulators of the avian endocrine system but relatively few studies have investigated their downstream effects on key morphological fitness‐related traits in free‐living populations. This study quantified endocrine–morphology relationships in free‐living Greenland Barnacle Geese Branta leucopsis that breed in the high Arctic. CORT and DHEA were extracted from feather and blood samples and tested for relationships with three morphological traits associated with survival and reproduction: bodyweight, body size and facial plumage coloration. We expected CORT concentration to be higher in birds with less favourable morphological traits (i.e. lighter, smaller and less attractive) and DHEA to be higher in birds with more favourable traits (i.e. heavier, bigger and more attractive). As expected, individuals with higher CORT during the post‐breeding moult (July/August) had significantly lower bodyweight during the following winter (November–April). In contrast, we found no robust DHEA–morphology relationships and no statistically significant relationship between CORT and body size or facial plumage. Overall, this study provides evidence of a negative relationship between CORT and bodyweight extending across different seasons of the annual cycle in a long‐distance migrant. This is of particular interest because bodyweight fluctuates rapidly in response to environmental resources and is closely linked to both survival and reproductive success in this species. Understanding the relationship between CORT and key morphological traits is important because endocrine‐disrupting contaminants in the Arctic increasingly interfere with CORT function in birds, including Barnacle Geese, and based on the results of this study may have consequences for bodyweight regulation.

中文翻译：

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北极迁徙鸟类的蜕皮季节皮质酮与冬季体重相关

在脊椎动物中，内分泌系统将环境变化转化为生理反应，自然选择可对这些反应做出反应，以调节个体的适应能力并最终调节种群动态。皮质酮（CORT）和脱氢表雄酮（DHEA）是禽类内分泌系统的重要调节剂，但相对较少的研究研究了它们对自由生活人口的主要形态健康相关性状的下游影响。这项研究量化了自由生活的格陵兰藤壶鹅黑雁的内分泌-形态关系在北极高海拔地区繁殖。从羽毛和血液样本中提取CORT和DHEA，并测试其与生存和繁殖相关的三个形态特征的关系：体重，体型和面部羽毛着色。我们预计形态特征较差（即较轻，更小且吸引力较小）的鸟的CORT浓度较高，而性状较有利（即较重，较大且更吸引人的鸟类）的DHEA较高。正如预期的那样，繁殖后蜕皮期（7月/ 8月）中CORT较高的个体在随后的冬季（11月至4月）中体重显着降低。相反，我们发现DHEA与形态之间没有牢固的关系，CORT与体型或面部羽毛之间也没有统计学上的显着关系。总体，这项研究提供了证据，证明长途移民的CORT与体重在年周期的不同季节之间呈负相关。这是特别令人感兴趣的，因为体重会随着环境资源的变化而迅速波动，并且与该物种的生存和生殖成功密切相关。了解CORT与关键形态特征之间的关系非常重要，因为北极的内分泌干扰污染物越来越多地干扰包括藤壶鹅在内的鸟类的CORT功能，并且基于这项研究的结果可能会对体重调节产生影响。这是特别令人感兴趣的，因为体重会随着环境资源的变化而迅速波动，并且与该物种的生存和生殖成功密切相关。了解CORT与关键形态特征之间的关系非常重要，因为北极的内分泌干扰污染物越来越多地干扰包括藤壶鹅在内的鸟类的CORT功能，并且基于这项研究的结果可能会对体重调节产生影响。这是特别令人感兴趣的，因为体重会随着环境资源的变化而迅速波动，并且与该物种的生存和生殖成功密切相关。了解CORT与关键形态特征之间的关系非常重要，因为北极的内分泌干扰污染物越来越多地干扰包括藤壶鹅在内的鸟类的CORT功能，并且基于这项研究的结果可能会对体重调节产生影响。