Ecology Colloquium Series - Hot and bothered: maternal stress alters metabolic rate and thermal sensitivity in lizard embryos

November 16, 2016 @ 12:20 pm to 01:10 pm

Dustin Owen, Penn State

301D Life Sciences

Biomedical and ecological researchers have long understood the adaptive significance of maternal stressors in programing offspring phenotypes. This process is usually done via the exposure of the offspring to maternal glucocorticoids, such as corticosterone (CORT). 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), when they cannot behaviorally defend themselves. Embryo heart rate was affected by an interaction between maternal treatment (stressed mothers vs. control mothers) and temperature, with embryos of stressed mothers having greater heart rates at higher temperatures than the embryos of control mothers. Additionally, embryo heart rate has higher in larger eggs and decreased through the day. Maternal stress appears to alter the pre-natal physiology of fence lizards, likely resulting in faster developmental rates. This could be advantageous for environmentally stressed populations, as it would limit the amount of time the offspring spend in their immobile egg state. This study highlights the importance of maternal stress in determining pre-natal offspring phenotype.

Contact

Dr. David Eissenstat
dme9@psu.edu