Selective disappearance of great tits with short telomeres in urban areas

• Published in: Proceedings of the Royal Society. B, Biological sciences Vol. 284; no. 1862; pp. 1 - 8
• Main Authors: Salmón, Pablo, Nilsson, Johan F., Watson, Hannah, Bensch, Staffan, Isaksson, Caroline
• Format: Journal Article
• Language: English
• Published: THE ROYAL SOCIETY 13.09.2017
• Subjects: ECOLOGY
• ISSN: 0962-8452; 1471-2954

Urban environments pose novel challenges, as well as opportunities, for urban-dwelling wildlife. Although differences have been reported in several 284: 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 pronounced in the urban environment, resulting in a longer average TL among the adult population. However, following recruitment, we found no difference in the relationship between TL and survival between the urban and rural environments. This indicates that the urban environment has negative effects in early life, while during later life the benefits could potentially outweigh the costs.