Meeting Abstract
Maternal effects can have positive or negative effects on maternal and offspring fitness, and are likely to be influenced by the evolutionary history of a population. Here we evaluate the influence of maternal hormonal state on offspring development in three populations of threespine stickleback (Gasterosteus aculeatus) that differ naturally in the presence and intensity of cannibalistic foraging groups to understand how evolutionary history with a potential stressor shifts the female stress response and influences offspring phenotype. We imposed a cannibalism-related challenge (post-ovulatory egg retention) and measured subsequent maternal, egg, and fry hormone levels, as well as fry growth and behavior. Females did not show elevated cortisol with forced egg retention although decreases in testosterone and estrogen occurred, consistent with expected shifts post ovulation. Although maternal titers did not change, egg cortisol levels in one population were affected by treatment and correlated with differences in fry stress response at three months of age. In two populations, declines in maternal testosterone were paralleled in egg hormone levels. Overall, the maternal challenge significantly reduced fry growth rate and feeding performance in the first month of life, and modestly increased recovery time after a startling stimulus. While maternal response to a natural challenge did not differ between populations, the results here show evolved differences in the consequences for offspring in the face of such challenge.
