A new study published in Ecological and Evolutionary Physiology reveals a surprising link between cellular aging markers and survival in black-legged kittiwakes (members of the gull family).
In “ Who’s coming home? Shorter early-life telomeres predict return to the natal colony in an Arctic seabird ” authors Jingqi Corey Liu, Olivier Chastel, Christophe Barbraud, Claus Bech, Pierre Blévin, Paco Bustamante, Børge Moe, Elin Noreen, and Frédéric Angelier found that kittiwake chicks with shorter telomeres were more likely to return to their birthplace as adults, contradicting predictions that longer telomeres would indicate better survival prospects.
Telomeres are protective DNA sequences at the ends of chromosomes that typically shorten with age and cellular stress. Scientists have long viewed longer telomeres as a sign of good health and higher fitness. However, this international study of 46 chicks monitored over six years in Svalbard, Norway, suggests the relationship is more nuanced than previously thought.
“Such complex results may be due to the resource allocation trade-off between growth and telomere maintenance,” the authors write, after discovering that in broods of two chicks—where sibling competition is more intense—larger individuals tended to have both higher-trophic-level diets (indicated by nitrogen stable isotopic values) and shorter telomeres.
“This suggests that sibling competition might have imposed stronger resource constraints on the chicks, making them prioritize the limited resources towards growth at the expense of telomere length,” they write.
The authors used Southern blot analysis to measure telomere length in red blood cells from 30-day-old chicks. Nitrogen stable isotope analysis (δ15N) revealed what trophic level of prey each chick was receiving, with higher values indicating more fish, which are of higher trophic levels and possibly more nutritious, rather than marine invertebrates. The team scanned the colony every breeding season from 2011 to 2016 to track which individuals returned to their birthplace.
The researchers propose that in challenging conditions, chicks may strategically invest in immediate survival advantages like body size rather than maintaining long telomeres, whose costs “might be paid only later in life.” Given that body size is crucial for young seabirds' survival and is locked in during development, prioritizing growth over telomere maintenance may ultimately improve long-term survival chances.
The findings highlight a caveat for using telomere length as an indicator of Darwinian fitness in the wild. “Our study supports that early-life telomere length can be a predictor of later-life performance, but it should be used with caution when considering the effect of the resource-allocation trade-off with growth, which can influence the direction of prediction,” the authors conclude.
Ecological and Evolutionary Physiology primarily publishes original research examining fundamental questions about how the ecological environment and/or evolutionary history interact with physiological function, as well as the ways physiology may constrain behavior. For EEP , physiology denotes the study of function in the broadest sense, across levels of organization from molecules to morphology to organismal performance and on behavior and life history traits.
Contact: Mallory Gevaert / mgevaert@uchicago.edu
Ecological and Evolutionary Physiology
Who’s Coming Home? Shorter Early-Life Telomeres Predict Return to the Natal Colony in an Arctic Seabird