Sex-specific consequences of life in the city
Sex-specific consequences of life in the city
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DOI：
10.1093/beheco/arl050
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发表时间：
2007-01-01
影响因子：
2.4
通讯作者：
Wingfield, John C.
中科院分区：
文献类型：
--
作者：
Bonier, Frances;Martin, Paul R.;Wingfield, John C.
绝大多数物种被排除在人类主导的景观之外，但一些物种坚持下来，似乎茁壮成长，尽管面临着在较少受干扰的栖息地不会遇到的挑战。皮质类固醇（cort）分泌可能在使动物应对城市繁殖栖息地方面发挥重要作用，因为它有助于调节对环境挑战的生理和行为反应。在这里，我们提出了关于城市动物皮质醇分泌的3个假设的检验：1)环境挑战在城市和农村栖息地之间存在差异，这反映在这些栖息地类型中繁殖的动物皮质醇分泌水平的不同上；2)种群内皮质醇水平的变化与适应性相关；3)寄生虫负荷是皮质醇水平变化与繁殖成功之间的机制联系之一。城市生境雄性白冠麻雀的皮质酮基线水平显著高于农村生境雄性，而雌性白冠麻雀的皮质酮基线水平在两种生境类型间无显著差异。为了评估激素水平变化的适应度相关性，我们监测了一个城市人群的季节性繁殖成功率，发现基线皮质酮水平可预测雌性而非雄性的繁殖成功率：皮质酮水平较高的雌性繁殖后代较少。数据并未表明皮质酮水平与健康之间存在直接关系，而是表明激素分泌、领地质量、身体状况和繁殖成功率之间存在间接关系。有血寄生虫的雌性比没有血寄生虫的雌性有更低的嗜异性淋巴细胞比率，更低的身体状况评分，更少的交配，更少的后代。相比之下，寄生虫对雄性的繁殖成功率没有负面影响，但与身体状况下降有关。皮质酮水平在携带和不携带寄生虫的鸟类之间没有差异。在对所有3个假设的测试中，我们发现了性别特异性的影响，强调了在研究对干扰的生理反应时考虑性别的重要性。
The vast majority of species are excluded from human-dominated landscapes, but some species persist and appear to thrive, despite facing challenges they would not encounter in less disturbed habitat. Corticosteroid (cort) secretion may play a significant role in enabling an animal to cope with urban breeding habitat because it helps mediate physiological and behavioral responses to environmental challenges. Here we present tests of 3 hypotheses relating to cort secretion in urban animals: 1) environmental challenges vary between urban and rural habitat, as reflected in differing levels of cort secretion in animals breeding in these habitat types, 2) there are fitness correlates associated with variation in cort levels within populations, and 3) parasite load is one of the mechanistic links between variation in cort levels and reproductive success. Male white-crowned sparrows (Zonotrichia leucophrys) in urban habitat had significantly higher baseline corticosterone levels than males in rural habitat, whereas female Z. leucophrys' hormone levels did not differ between the 2 habitat types. To assess the fitness correlates of variation in hormone levels, we monitored seasonal reproductive success in one urban population and found that baseline corticosterone levels were predictive of female, but not male, reproductive success: females with higher corticosterone fledged fewer offspring. Data do not suggest a direct relationship between corticosterone levels and fitness and instead indicate an indirect relationship between hormone secretion, territory quality, body condition, and reproductive success. Females with blood parasites had lower heterophil:lymphocyte ratios, lower body condition scores, fewer mates, and fledged fewer offspring than females without parasites. In contrast, parasites did not negatively affect reproductive success in males but were associated with reduced body condition. Corticosterone levels did not differ between birds with and without parasites. In tests of all 3 of our hypotheses, we found sex-specific effects, highlighting the importance of considering sex in investigation of physiological responses to disturbance.