Short-Term Telomere Elongation in Breeding Adults of a Long-Lived Seabird

AbstractTelomere dynamics have been linked to differences in reproductive effort across vertebrates. In the Cocos booby (Sula brewsteri), we predicted that parents' telomeres would shorten according to their breeding effort during incubation. During mid-incubation, we blood-sampled 24 adults to estimate telomere length by a quantitative polymerase chain reaction and recorded their body mass, clutch size, and hatching success. At the end of incubation, a second body mass measurement and blood sample were collected. Unexpectedly, parents' telomere length increased throughout incubation. Individuals with two-egg clutches, higher hatching success, and increased body mass exhibited greater telomere elongation. Thus, telomere dynamics did not reflect costs of reproductive effort. The results suggest that telomeres elongate, probably depending on individual quality differences, as proposed by the excess resources elongation hypothesis. Future studies should investigate whether the observed short-term telomere elongation is widespread in breeding animals, as it may be part of a potential mechanism for resilience to predictable stressful events like reproduction.