The relationship between fitness and baseline glucocorticoids in a passerine bird
The relationship between fitness and baseline glucocorticoids in a passerine bird
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DOI：
10.1016/j.ygcen.2008.12.013
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发表时间：
2009-08-01
影响因子：
2.7
通讯作者：
Robertson, Raleigh J.
中科院分区：
文献类型：
--
作者：
Bonier, Frances;Moore, Ignacio T.;Robertson, Raleigh J.
糖皮质激素（皮质激素）越来越多地应用于自由放养动物的研究中，基线皮质激素水平升高通常被认为表明个体或群体状况更差，适应性更低（皮质激素适应性假说）。皮质和健身之间的关系很少得到验证，研究皮质-健身关系的研究往往发现结果与皮质-健身假说不一致。这些研究的不一致性可能部分是由于生活史各个阶段的皮质-适应性关系的变化。在这里，我们解决了以下问题，在自由放养的树燕子（Tachycineta双色）的两年研究：（1）基线皮质醇水平与健康的生活史阶段？(2)皮质激素与健康的关系在不同的生命史阶段会有所不同吗？(3)皮质-适应性关系在个体生命史的不同阶段是否存在差异？(4)生殖努力影响皮质激素水平，皮质激素水平影响生殖努力吗？我们测量了已知繁殖阶段的雌鸟的基线皮质激素和健身成分。我们发现基线皮质激素水平和健身在一些生活史阶段之间的相关性，但这种关系从早期繁殖期间的负向转变为晚期繁殖期间的正向，即使在同一个体内。在雏鸟期基线皮质激素和健身组件之间的正相关关系表明，生殖投资可能会引起更高的皮质激素水平的反馈，重新分配更多的努力，在关键时期的雏鸟供应繁殖。我们的研究结果提供了质疑Cort健身假说的理由，并对CORT措施在监测保护关注的种群状况中的应用产生影响。(C)2008年爱思唯尔公司All rights reserved.
Glucocorticoid (cort) hormones are increasingly applied in studies of free-ranging animals, with elevated baseline cort levels generally assumed to indicate individuals or populations in worse condition and with lower fitness (the Cort-Fitness Hypothesis). The relationship between cort and fitness is rarely validated and studies investigating the cort-fitness relationship often find results inconsistent with the Cort-Fitness Hypothesis. The inconsistency of these studies may result in part from variation in the cort-fitness relationship across life history stages. Here we address the following questions in a two-year study in free-ranging tree swallows (Tachycineta bicolor): (1) Do baseline cort levels correlate with fitness within a life history stage? (2) Does the cort-fitness relationship vary across different life history stages ? (3) Does the cort-fitness relationship vary across life history stages within an individual? (4) Does reproductive effort influence cort levels, and do cort levels influence reproductive effort? We measured baseline cort and fitness components in female birds of known breeding stages. We find correlations between baseline cort levels and fitness within some life history stages, but the relationship shifts from negative during early breeding to positive during late breeding, even within the same individuals. A positive relationship between baseline cort and fitness components during the nestling period suggests that reproductive investment may elicit higher cort levels that feedback to reallocate more effort to reproduction during critical periods of nestling provisioning. Our findings provide reason to question the Cort-Fitness Hypothesis, and have implications for the application of cort measures in monitoring the condition of populations of conservation concern. (C) 2008 Elsevier Inc. All rights reserved.