Rebolo-Ifrán Natalia, Carrete Martina, Sanz-Aguilar Ana, Rodríguez-Martínez Sol, Cabezas Sonia, Marchant Tracy A, Bortolotti Gary R, Tella José L
Departamento de Ecología, Genética y Evolución &IEGEBA-CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina.
Department of Physical, Chemical and Natural Systems, Universidad Pablo de Olavide, Sevilla, Spain.
Sci Rep. 2015 Sep 8;5:13723. doi: 10.1038/srep13723.
Urban endocrine ecology aims to understand how organisms cope with new sources of stress and maintain allostatic load to thrive in an increasingly urbanized world. Recent research efforts have yielded controversial results based on short-term measures of stress, without exploring its fitness effects. We measured feather corticosterone (CORTf, reflecting the duration and amplitude of glucocorticoid secretion over several weeks) and subsequent annual survival in urban and rural burrowing owls. This species shows high individual consistency in fear of humans (i.e., flight initiation distance, FID), allowing us to hypothesize that individuals distribute among habitats according to their tolerance to human disturbance. FIDs were shorter in urban than in rural birds, but CORTf levels did not differ, nor were correlated to FIDs. Survival was twice as high in urban as in rural birds and links with CORTf varied between habitats: while a quadratic relationship supports stabilizing selection in urban birds, high predation rates may have masked CORTf-survival relationship in rural ones. These results evidence that urban life does not constitute an additional source of stress for urban individuals, as shown by their near identical CORTf values compared with rural conspecifics supporting the non-random distribution of individuals among habitats according to their behavioural phenotypes.
城市内分泌生态学旨在了解生物体如何应对新的压力源，并维持体内平衡负荷，以便在日益城市化的世界中茁壮成长。近期的研究基于短期压力测量得出了有争议的结果，却未探究其对适应性的影响。我们测量了城市和农村穴小鸮的羽毛皮质酮（CORTf，反映数周内糖皮质激素分泌的持续时间和幅度）以及随后的年度存活率。该物种在对人类的恐惧（即飞行起始距离，FID）方面表现出高度的个体一致性，这使我们能够假设个体根据其对人类干扰的耐受性在不同栖息地之间分布。城市穴小鸮的FID比农村穴小鸮短，但CORTf水平并无差异，也与FID无关。城市穴小鸮的存活率是农村穴小鸮的两倍，且与CORTf的关系在不同栖息地有所不同：虽然二次关系支持城市穴小鸮的稳定选择，但高捕食率可能掩盖了农村穴小鸮中CORTf与存活率的关系。这些结果表明，城市生活对城市个体而言并非额外的压力源，这体现在它们与农村同种个体相比，CORTf值几乎相同，这也支持了个体根据其行为表型在不同栖息地间的非随机分布。
