The influence of maternal glucocorticoids on offspring phenotype in high- and low-risk environments
MacLeod, Kirsty J. et al. (2021), The influence of maternal glucocorticoids on offspring phenotype in high- and low-risk environments, Dryad, Dataset, https://doi.org/10.5061/dryad.kd51c5b6g
Elevated maternal glucocorticoid levels during gestation can lead to phenotypic changes in offspring via maternal effects. Although such effects have traditionally been considered maladaptive, maternally derived glucocorticoids may adaptively prepare offspring for their future environment depending upon the correlation between maternal and offspring environments. Nevertheless, relatively few studies test the effects of prenatal glucocorticoid exposure across multiple environments. We tested the potential for ecologically relevant increases in maternal glucocorticoids in the eastern fence lizard (Sceloporus undulatus) to induce adaptive phenotypic changes in offspring exposed to high or low densities of an invasive fire ant predator. Maternal treatment had limited effects on offspring morphology and behaviour at hatching, but by 10 days of age, we found maternal treatment interacted with offspring environment to alter anti-predator behaviours. We did not detect differences in early-life survival based on maternal treatment or offspring environment. Opposing selection on anti-predator behaviours from historic and novel invasive predators may confound the potential of maternal glucocorticoids to adaptively influence offspring behaviour. Our test of the phenotypic outcomes of transgenerational glucocorticoid effects across risk environments provides important insight into the context-specific nature of this phenomenon and the importance of understanding both current and historic evolutionary pressures.
Gravid adult female fence lizards (Sceloporus undulatus) were captured in Alabama in Spring 2017. They were treated with glucocorticoid hormone during gravidity (control group given oil vehicle only). Resulting offspring were measured, including behavioural assays, on day 1 (i.e. birth). They were then placed into enclosures designed to have either low or high risk of predation from invasive fire ants (a predator of juvenile lizards). Habitat use, home range, behaviour and survival were monitored for 10 days.