Meeting Abstract
Sublethal stressors will likely mediate an organism’s response to climate change. Mobile animals can use behavioral thermoregulation to buffer the effects of environmental changes, but animals in sessile stages of ontogeny are vulnerable to warming. For example, lizard embryos are exposed to recurrent thermal stress as they develop in shallow nests. Previous research has shown Eastern fence lizard (Sceloporus undulatus) embryos will succumb to cardiac arrest under acute exposures to nesting temperatures at or above 41.5°C , which is beyond the range of temperatures experienced in contemporary climates. But how does exposure to sublethal high temperatures due to climate warming affect embryos? We reared S. undulatus embryos under three thermal regimes based on soil temperature data—a contemporary regime with a maximum daily temperature (Tmax) of 32.1°C, and two regimes to simulate warming scenarios in which the Tmax was raised to 35.6°C and 39.1°C. Clutches were divided evenly among the treatments to examine impacts of the different thermal cycles on embryo physiology. Hatchlings were then raised in a common environment. To evaluate the capacity for acclimation to the embryonic thermal environment, we measured hatchling growth, metabolic rates, preferred temperatures, and sprint speeds. Results from this study will highlight important physiological constraints on embryonic lizards and the impacts of those constraints on post-hatching phenotypes. Future research should examine the long-term sublethal effects of warming as they occur throughout stages of ontogeny.
