Abstract
Maternal effects affect offspring phenotype and fitness. However, the roles of offspring sex-specific sensitivity to maternal glucocorticoids and sex-biased maternal investment remain unclear. It is also uncertain whether telomere length (a marker associated with lifespan) depends on early growth in a sex-specific manner. We assessed whether maternal traits including corticosterone (CORT; the main avian glucocorticoid) and in ovo growth rate are sex-specifically related to offspring CORT exposure, relative telomere length (RTL) and body condition in eiders (Somateria mollissima). We measured feather CORT (fCORT), RTL and body condition of newly hatched ducklings, and growth rate in ovo was expressed as tarsus length at hatching per incubation duration. Maternal traits included baseline plasma CORT, RTL, body condition and breeding experience. We found that fCORT was negatively associated with growth rate in daughters, while it showed a positive association in sons. Lower offspring fCORT was associated with higher maternal baseline plasma CORT, and fCORT was higher in larger clutches and in those hatching later. The RTL of daughters was negatively associated with maternal RTL, whereas that of males was nearly independent of maternal RTL. Higher fCORT in ovo was associated with longer RTL at hatching in both sexes. Duckling body condition was mainly explained by egg weight, and sons had a slightly lower body condition. Our correlational results suggest that maternal effects may have heterogeneous and even diametrically opposed effects between the sexes during early development. Our findings also challenge the view that prenatal CORT exposure is invariably associated with shorter telomeres.
Highlights
Early-life exposure to glucocorticoids may have a profound effect on offspring phenotype, either preparing the offspring for their postnatal environment or decreasing their fitness value (Haussmann et al 2012; Herborn et al 2014; Monaghan and Haussmann 2015)
Duckling feather CORT (fCORT) showed relatively low but significant within-brood repeatability (r = 0.25, 95% CI 0.13–0.37, P < 0.001), which suggests that the fCORT levels of ducklings from the same brood resemble each other
Offspring sex and growth rate in ovo interactively explained variation in offspring fCORT (Table 1): lower fCORT of daughters was associated with increasing growth rate, while fCORT levels and growth were positively correlated in sons (Fig. 1)
Summary
Early-life exposure to glucocorticoids may have a profound effect on offspring phenotype, either preparing the offspring for their postnatal environment or decreasing their fitness value (Haussmann et al 2012; Herborn et al 2014; Monaghan and Haussmann 2015). Together with maternal attributes such as breeding experience, body condition and reproductive investment, maternal glucocorticoids are thought to shape the early-life environment of offspring (Love et al 2005; Monaghan 2008). Oecologia (2020) 192:43–54 glucocorticoids on the developing embryo can differ depending on its sex (Butkevich et al 2009; Jimeno et al 2017). Such sex-specific effects of maternal glucocorticoids may arise due to differential regulation of the hypothalamic–pituitary axis between the sexes (Schmidt et al 2014). Postnatal phenotypic differences between the sexes may be the product of a complex interplay between sex-specific maternal deposition of substances into eggs, the ability of embryos to modulate the effects of these substances, and interactions between maternal deposition and embryonic modulation (Vassallo et al 2014; Groothuis et al 2019)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
