Telomere length is a strong predictor of foraging behavior in a long‐lived seabird

Abstract

Abstract. Telomeres are an increasingly studied component of physiological ecology. However, in longlived birds a large telomere loss with chronological age is not the norm. Telomeres are now regarded less as a chronological aging tool and more as an indicator of individual quality, residual lifespan, or biological age. If telomeres indicate biological aging processes, then they should also be associated with other variables that change with age, especially foraging and reproductive behaviors. This study compared telomere length to a suite of foraging parameters in Thick-billed Murres breeding on three colonies in the Bering Sea. Telomere length, environmental conditions at colonies, and sex played pivotal roles in determining foraging habitat selection. Spatial habitat use, foraging efficiency, and prey selection variables all changed with telomere length. The behavioral evidence indicates that despite losing telomeres, birds with short telomere length retain their ability to use the environment efficiently. This indicates that aging birds remain behaviorally flexible, despite paying physiological costs. Changes in spatial use were largely sex-dependent: females and males differed in their use of the environment as telomere lengths declined. Prey selection was related to telomere length and colony; changes in murre trophic level depended on telomere length, but their direction also depended on habitat quality. We found much support for the continued able functioning of birds with shorter telomeres, indicating that physiological aging does not carry only costs. Murres appear to modify their behavior depending on environmental conditions as their physiological reserves decline.

Relationship between telomere dynamics and movement and behavior during winter in the thick‑billed murre

“…ΔTL was usually calculated from 1 yr to the following year, but in 4 cases telomeres were re-sampled after 2 yr; in these cases, ΔTL was divided by 2 to indicate mean annual change. In addition to wintering variables, we include other measures likely to affect migration and TL: year (of global location sensing deployment, first capture), sex (Young et al 2013(Young et al , 2015, colony (Young et al 2015), body size (Barrett et al 2013, Orben et al 2015, body mass, and the annual change in body mass. Twenty-three birds had complete data and could be used in this analysis.…”

“…Long TL may indicate high-quality individuals (Le Vaillant et al 2015) that may have invested heavily in offspring, behaviorally or energetically. TL in murres is associated with breeding season foraging patterns, especially depth and choice of water masses (Young et al 2015). Behavioral changes such as increased depth and trip duration led to higher post-breeding stress in rhinoceros auklets , and similar patterns may drive post-breeding stress in murre fCORT as well.…”

“…Telomeres were measured using the telomere restriction fragment assay following Young et al (2015). Briefly, 5 µl of packed red blood cells were extracted Young et al (2015).…”

“…Briefly, 5 µl of packed red blood cells were extracted Young et al (2015). Longitudinal samples from the same individual were analyzed in adjacent lanes, and gels included 2 control samples per gel to determine intra-assay variability (CV = range/mean; mean CV = 4.7 ± 1.4%).…”

“…Some studies, especially of longlived species, have not found relationships with longevity (Pauliny et al 2006) or changes in body mass and survival (Pauliny et al 2012). In thick-billed murres, TL is related to physiological stress (baseline corticosterone) (Young et al 2016) and interacts with habitat quality to predict patterns in foraging behavior during the breeding season (Young et al 2015). Links to other phases of the annual cycle, however, have not been tested.…”