Meeting Abstract
Recently in vertebrates, maternally-derived stress hormones, glucocorticoids, have been shown as a significant inducer of transgenerational phenotypic plasticity. Offspring phenotypic responses are often interpreted as unavoidable negative side effects of maternal stress. Growing evidence supports the adaptive hypothesis for maternal stress whereby phenotypic responses in offspring may be adaptively matched to the local environment. While many studies have examined how maternal stress has influenced the post-natal trails of offspring, few studies have addressed the effects of maternal stress on the pre-natal life stage. We tested the hypothesis that stressed female eastern fence lizards (Sceloporus undulatus) have embryos that have higher metabolic rates (i.e. heart rates). This should result in faster growth, and decrease the amount of time the embryos spend in their most vulnerable stage of life (egg stage). We found that embryos of stressed mothers had greater heart rates at higher temperatures, but similar heart rates at lower temperatures, compared to embryos of control mothers. Additionally, embryo heart rate was higher in larger eggs and decreased through the day. Thus, maternal stress appears to alter the pre-natal physiology of fence lizards. This likely would result in faster developmental rates, earlier hatching, and larger body size of offspring from maternally stressed females. These consequences of maternal stress could be adaptive in high stress environments, increasing fitness of populations faced with increased predation, heat stress, and/or competition.
