Selective disappearance of great tits with short telomeres in urban areas

Urban environments pose novel challenges, as well as opportunities, for urban-dwelling wildlife. Although differences have been reported in several phenotypic traits (e.g. morphology, physiology and behaviour) between urban and rural populations, it is poorly understood whether this affects individual fitness. Telomere dynamics are posited as one possible mechanism underlying senescence and mortality. It was recently shown that telomere shortening is accelerated when growing up in an urban, compared with a rural, environment. However, the implications of accelerated telomere attrition for fitness are still unclear. Here, we examine the relationship between telomere length (TL) and survival in a bird common to urban and rural environments, and during both early and later life. The results reveal that TL is a strong predictor of post-fledging survival and recruitment in both habitats but, crucially, selective disappearance of individuals with short telomeres early in life is more pronounc...城市环境为栖息其中的野生动物带来了全新的挑战与机遇。尽管已有研究报道了城市与乡村种群在多项表型性状（phenotypic traits，如形态学、生理学与行为学）上的差异，但此类差异是否会影响个体适合度（fitness），目前仍知之甚少。端粒动态（telomere dynamics）被认为是介导衰老与死亡的潜在机制之一。近期研究表明，相较于乡村环境，在城市环境中成长会加速端粒缩短（telomere shortening）。然而，端粒加速损耗（telomere attrition）对个体适合度的影响仍不明确。本研究以一种广泛分布于城市与乡村生境的鸟类为研究对象，探究了其生命早期与后期的端粒长度（Telomere length, TL）与存活率之间的关联。研究结果显示，在两类生境中，端粒长度均能显著预测个体出飞后存活率（post-fledging survival）与种群补充率（recruitment）；尤为关键的是，生命早期端粒较短的个体发生选择性消失（selective disappearance）的现象更为显著……