HARMS, H.K.*; BOWDEN, R.M.; Illinois State University; Illinois State University: Effects of corticosterone exposure during development on hatchling red-eared slider turtles, Trachemys scripta

In oviparous organisms maternal physiology has the potential to influence offspring, one route of influence being the transfer of steroids to yolk. Due to the lipophilic nature of steroids, they may become trapped in the yolk during folliculogenesis, resulting in both positive and negative impacts on the offspring. Animals in many taxa secrete glucocorticoids in response to stressors, and if they are transferred to the yolk, as are other steroids, females subjected to stressors during egg formation could produce eggs containing increased levels of glucocorticoids. We investigated the effects of elevated corticosterone (CORT) on the development of red-eared sliders by applying CORT (0, 0.01, 0.1, and 1.0 μg in 5 μl ethanol) to the eggshell five days after oviposition. We compared length of incubation, hatchling mass, survival, and developmental abnormalities between the four treatments. CORT dose did not affect hatchling mass. Eggs receiving 0.1 μg CORT had the longest incubation period of the four doses. In addition, mortality prior to hatching was positively correlated with increasing CORT: the mortality rate in the 1.0 μg dosage group was more than three times higher than in the 0.1 μg group. There was an increased incidence of developmental abnormalities in the 1.0 μg CORT treatment, including scute abnormalities and stubby tails. Because exposure to CORT during development impacts characteristics such as survival and incubation length and also seems to affect morphological development, other processes may be affected as well. For example, high levels of CORT have been linked to decreased immune function in various taxa, so exposure during development could potentially impact the development and function of the immune system.