Tara Cox, Thomas J Brown, Alexandra M Sparks, Jan Komdeur, Terry Burke, David S Richardson, Hannah L Dugdale 

Numerous studies have demonstrated that individuals within a species will consistently vary between one another in behavioural traits. A prominent adaptive explanation for such ‘animal personalities’ relates to an individual’s intrinsic state driving and/or being driven by behaviour. Telomeres – the protective caps at the end of chromosomes which exist in most organisms – have been proposed as a biomarker of an individual’s intrinsic state and mortality risk. It is, however, unclear the extent to which telomere dynamics are associated with repeatable behavioural traits, with only a handful of studies exploring this relationship to date. Here, we examined the relationship between relative telomere length and exploration of both a novel environment and novel object in a wild population of Seychelles warblers (Acrocephalus sechellensis). We tested for between-individual covariation between exploratory traits, as well as between-individual covariation among exploratory traits and both relative telomere length and change in telomere length over time. We found that individuals who explored a novel environment more, also explored a novel object more, and that there was a strong quadratic age effect on both exploratory measures. However, there was no between-individual relationship between exploratory traits and either relative telomere length or change in relative telomere length over time. When assessing covariation between intrinsic state and personality, our findings demonstrate the importance of: (1) considering longitudinal evidence, where there is an opportunity for environmental stressors to influence telomere dynamics; (2) considering potentially confounding factors related to within-individual vs between-individual processes; and, (3) investigating covariation across many taxa.