Sex-dependent effects of maternal stress: Stressed moms invest less in sons than daughters.

Abstract

Multigenerational effects can have important and sex-dependent effects on offspring. Sex allocation theory predicts that females should differentially invest in sons and daughters depending on sex-specific fitness returns and costs of investment. Maternal stress-relevant (glucocorticoid) hormones may be one mechanism driving this effect. We investigated how maternal stress hormones differentially affected sons and daughters by manipulating levels of the glucocorticoid, corticosterone (CORT), in gravid female eastern fence lizards (Sceloporus undulatus) and quantifying reproductive investment and sex ratio of resulting clutches, and the mass, snout-vent length, and body condition of sons versus daughters at hatching. We found no effect of maternal CORT-treatment on the number or size of eggs laid or on the sex ratio of resulting offspring, but sons of CORT-treated mothers were shorter, lighter, and of poorer body condition at hatching than were sons of control mothers. We found no difference in size or condition of daughters with maternal treatment. Our results suggest that maternal stress, mediated by elevations in maternal CORT concentrations, can have sex-specific effects on offspring manifesting as lower investment in sons.