Meeting Abstract
One of the most important decisions an oviparous mother can make is where to put her nest. This decision determines the environmental conditions experienced by developing embryos. For instance, Eastern fence lizards (Sceloporus undulatus) lay their eggs in shallow underground nests, where embryos are exposed to daily temperature fluctuations due to heat flux from the soil surface. Research on nesting behavior suggests S. undulatus females will travel long distances beyond their home ranges to nest in the warmest parts of the environment. Yet, rapid climate change is pushing conditions at those nest sites toward the physiological limits of developing embryos. Therefore, variation in nesting behavior could increase the potential for population persistence under warming conditions if fence lizards can also select cooler nest sites (shadier or deeper, e.g.). In 2015 and 2016, we conducted field research to examine nesting behavior in a S. undulatus population in South Carolina. We tracked gravid females using radio telemetry to locate nest sites and compare habitat use during the summer breeding season. Results showed lizards revisit nest sites annually, while exhibiting variation in nest site selection between clutches in the same season. Females traveled significantly greater distances and selected warmer, sunnier nest sites to lay their second clutches, compared to their first. Individual variation in nesting behavior could be advantageous to the population if alternative nest sites buffer offspring from the deleterious effects of rapid warming. In addition, variation in the thermal environment among nest sites within seasons could enable evolution of thermal physiology and persistence of the species under rapid climate change. Although, more research is needed to determine whether evolution rapid enough to keep pace with climate change is possible.
