TELOMERE LENGTH AT BIRTH: A PREDICTIVE BIOMARKER OF SURVIVAL TO MATURITY AND REPRODUCTIVE SUCCESS?

Abstract

Telomere dynamics is a subject of great interest in the field of evolutionary biology. An increasing number of studies have shown a link between telomere length and key life history traits such as longevity or aging. However, the majority of these studies focus on endotherms, especially humans. In contrast, we have a relatively poor understanding of how these links play out in ectotherms. In this study, I take advantage of a unique long-term data set, spanning more than 20 years, to study the link between telomere dynamics and life history traits in the spotted snow skink, Carinascincus ocellatus. I show that snow skinks experience high levels of juvenile mortality with only 19% of females born surviving to maturity and among those survivors, 47% live past their first year of reproduction. Despite numerous studies showing links between survival and telomere length of offspring, I found no evidence that survival was predicted by telomere length at birth, suggesting that telomere length is not the main determinant of early life or lifelong fitness for snow skinks. Additionally, there was no evidence of a link between telomere length at birth or reproductive effort and growth on survival to the second year of reproduction. I argue that this is either because telomere length at birth is a poor biomarker for intrinsic mortality risk or that extrinsic, rather than intrinsic, sources of mortality are more important during early life stages. More broadly, my study emphasizes the difference between ectotherms and endotherms and highlights the need for more studies on ectotherms to be able to understand telomere dynamics across both endothermic and ectothermic taxa.