Offspring of older breeders frequently show reduced longevity, which has been linked to shorter offspring telomere length. It is currently unknown whether such telomere reduction persists beyond a single generation, as would be the case if germline transmission is involved. In a within‐grandmother, multi‐generational study using zebra finches, we show that the shorter telomeres observed in F1 offspring of older mothers are sti...

This perspectives paper considers the value of studying telomere biology outside of a biomedical context. I provide illustrative examples of the kinds of questions that evolutionary ecologists have addressed in studies of telomere dynamics in non-model species, primarily metazoan animals, and what this can contribute to our understanding of their evolution, life histories and health. I also discuss why the predicted relationsh...

Heat waves are predicted to be detrimental for organismal physiology with costs for survival that could be reflected in markers of biological state such as telomeres. Changes in early life telomere dynamics driven by thermal stress are of particular interest during the early post‐natal stages of altricial birds because nestlings quickly shift from being ectothermic to endothermic after hatching. Telomeres of ectothermic and en...

Mitochondrial dysfunction and oxidative damage have long been suggested as critically important mechanisms underlying the ageing process in animals. However, conflicting data exist on whether this involves increased production of mitochondrial reactive oxygen species (ROS) during ageing. We employed high‐resolution respirometry and fluorometry on flight muscle (pectoralis major) and liver mitochondria to simultaneously examine...

Telomere dynamics could underlie life‐history trade‐offs among growth, size and longevity, but our ability to quantify such processes in natural, unmanipulated populations is limited. We investigated how 4 years of artificial selection for either larger or smaller tarsus length, a proxy for body size, affected early‐life telomere length (TL) and several components of fitness in two insular populations of wild house sparrows ov...

Telomere length and DNA methylation (DNAm) are two promising biomarkers of biological age. Environmental factors and life history traits are known to affect variation in both these biomarkers, especially during early life, yet surprisingly little is known about their reciprocal association, especially in natural populations. Here, we explore how variation in DNAm, growth rate, and early‐life conditions are associated with telo...

Early‐life telomere length (TL) is associated with fitness in a range of organisms. Little is known about the genetic basis of variation in TL in wild animal populations, but to understand the evolutionary and ecological significance of TL it is important to quantify the relative importance of genetic and environmental variation in TL. In this study, we measured TL in 2746 house sparrow nestlings sampled across 20 years and us...

Human activity is changing climatic conditions at an unprecedented rate. The impact of these changes may be especially acute on ectotherms since they have limited capacities to use metabolic heat to maintain their body temperature. An increase in temperature is likely to increase the growth rate of ectothermic animals, and may also induce thermal stress via increased exposure to heat waves. Fast growth and thermal stress are m...

The importance of parental contributions to offspring development and subsequent performance is self‐evident at a genomic level; however, parents can also affect offspring fitness by indirect genetic and environmental routes. The life history strategy that an individual adopts will be influenced by both genes and environment; and this may have important consequences for offspring. Recent research has linked telomere dynamics (...

Early environmental conditions can influence the pattern of growth and development. While poor conditions generally cause slower growth, normal adult size can still be reached if growth accelerates or is prolonged once conditions improve, but such catch‐up growth may have deleterious effects later in life. Here we investigate for the first time how decelerating as well as accelerating growth trajectories, manipulated independe...

Ecology Letters (2010) 13: 1435–1447 Abstract There is increasing evidence that some non‐essential substances or environmental stressors can have stimulatory or beneficial effects at low exposure levels while being toxic at higher levels, and that environmental ‘priming’ of certain physiological processes can result in their improved functioning in later life. These kinds of nonlinear dose–response relationships are referred t...

The concept of trade‐offs is central to our understanding of life‐history evolution. The underlying mechanisms, however, have been little studied. Oxidative stress results from a mismatch between the production of damaging reactive oxygen species (ROS) and the organism’s capacity to mitigate their damaging effects. Managing oxidative stress is likely to be a major determinant of life histories, as virtually all activities gene...