Nest cover and faecal glucocorticoid metabolites are linked to hatching success and telomere length in breeding Common Eiders (Somateria mollissima)

Abstract

Habitat-associated crypsis may affect perceived predation vulnerability, selecting for different predator avoidance strategies. Glucocorticoids could mediate the adjustment of escape responses to the extent of crypsis, introducing an overlooked source of variation in glucocorticoid–fitness relationships. However, prolonged exposure to elevated glucocorticoids may be costly, leading to accelerated telomere loss and, consequently, senescence. Here, we examined how nest cover and immunoreactive faecal glucocorticoid metabolite (fGCM) levels are linked to hatching success and telomere length in breeding female Common Eiders (Somateria mollissima (L., 1758)). We hypothesized that the degree of nest crypsis, reflecting differences in perceived predation risk, would moderate the relationship between reproductive success and fGCM levels. We also expected that telomere length would be shorter in birds with higher glucocorticoid concentration. Results showed that individuals with high fGCM levels had higher hatching success in nests with low cover, while low fGCM levels were more successful in well-concealed nests. We found that shorter telomeres were associated with high fGCM in nesting sites offering little cover and with low fGCM in well-concealed ones. This study provides the first evidence of habitat-dependent moderation of the relationships between stress physiology, telomere length and hatching success.

Do Telomeres Influence Pace‐of‐Life‐Strategies in Response to Environmental Conditions Over a Lifetime and Between Generations?

“…[49] Similarly, perceived predation risk (degree of nest crypsis) affected telomere length in hatching common eiders (Somateria mollissima), in which chicks hatching from uncovered nests have shorter telomeres. [50] The telomere-messenger hypothesis provides an adaptive explanation for these results. Hence, under high predation pressures, shorter telomeres would favor a fast pace-of life strategy and an increased investment in reproduction.…”

Sex-specific effects of the in ovo environment on early-life phenotypes in eiders

“…Every plate also included serial doubling dilutions of a standard sample, which was later used to construct standard curves. Further details on the application of the telomere assay to the current study population can be found elsewhere (Noreikiene et al 2017). The mean qPCR efficiencies as determined by the standard curves for telomere and gapdh reactions fell within the acceptable range of 85-115% (Bize et al 2009).…”

“…However, extreme caution needs to be exercised when attempting to draw parallels to our present study. This is because the RTL of adult female eiders shows no significant trend with age (Noreikiene et al 2017), and female age was not associated with offspring RTL (Table 2). Clearly, there is a need for further longitudinal analysis of the covariation between maternal and offspring RTL over the lifespan of females.…”

“…We measured relative telomere length (RTL) in red blood cells using real-time quantitative PCR (qPCR) (Cawthon 2002;Criscuolo et al 2009), using an assay that we have previously validated for use in female eiders (Noreikiene et al 2017). Genomic DNA was extracted using the salt-extraction method (Aljanabi and Martinez 1997) and DNA quality was controlled spectrophotometrically and with agarose gel electrophoresis.…”

Glucocorticoids, state-dependent reproductive investment and success in the face of danger in a long-lived bird

“…Telomere length may represent a complimentary measure of RRV. Thus, although the telomere length of adult female Eiders is not significantly associated with age or body condition, reproductive success may be achieved at the expense of telomere length (Noreikiene et al 2017). Female reproductive success was measured as proportional hatching success.…”