Tue, Aug 03, 2021:On Demand
Background/Question/Methods
Colorful traits that signal individual quality to conspecifics (i.e. ornaments) have important relationships with individual condition and physiology. However, maternal effects such as genetic inheritance and the physiological environment experienced by the embryo could potentially affect the development of ornaments. In parallel, it is unclear why many species exhibit sexual ornaments that are not fully dimorphic between sexes, and whether maternal ornamentation may be indirectly adaptive via genetic inheritance in male offspring. We examined the influence of prenatal effects and maternal phenotype on the development of a condition-dependent visual signal in the lizard Sceloporus undulatus. We measured testosterone (T) and the stress-relevant hormone, corticosterone (CORT), and the color saturation and patch area of blue ventral ornaments in field-caught gravid females. Resulting offspring were raised in the lab, and we explored how maternal traits and hormones correlated with their offspring’s survival and ornament quality at maturity.
Results/Conclusions Females with high CORT and with more saturated ornaments during pregnancy had offspring with lower survival to maturity. Further, maternal ornament saturation and area were negatively correlated with those of male offspring, and uncorrelated with those in female offspring. Maternal CORT exhibited an independent, negative effect on ornament saturation of offspring of both sexes. Our results suggest that concentrations of a stress-relevant hormone during pregnancy and maternal ornamentation can affect fitness by reducing offspring survival to maturity and impairing the expression of a condition-dependent signal in males. This mechanism may occur in concert with social costs associated with the expression of ornamentation in mothers. Transgenerational costs of female ornamentation and prenatal stress may be important, interdependent drivers of balancing selection and intralocus sexual conflict over signaling traits.
Results/Conclusions Females with high CORT and with more saturated ornaments during pregnancy had offspring with lower survival to maturity. Further, maternal ornament saturation and area were negatively correlated with those of male offspring, and uncorrelated with those in female offspring. Maternal CORT exhibited an independent, negative effect on ornament saturation of offspring of both sexes. Our results suggest that concentrations of a stress-relevant hormone during pregnancy and maternal ornamentation can affect fitness by reducing offspring survival to maturity and impairing the expression of a condition-dependent signal in males. This mechanism may occur in concert with social costs associated with the expression of ornamentation in mothers. Transgenerational costs of female ornamentation and prenatal stress may be important, interdependent drivers of balancing selection and intralocus sexual conflict over signaling traits.