Meeting Abstract

S8.2-1  Monday, Jan. 6 10:30  The importance of fluctuating temperatures for offspring phenotype in turtles with temperature-dependent sex determination BOWDEN, RM*; PAITZ, RT; Illinois State University; University of Illinois rmbowde@ilstu.edu

In species with temperature-dependent sex determination (TSD), the temperatures experienced during incubation are correlated with the resultant sex of the offspring. It has also been shown that incubation temperature can influence other phenotypic characteristics of the offspring beyond sex in species with TSD, indicating that temperature can have broad influence over the resulting phenotype. Unfortunately, much of the empirical work demonstrating the relationship between temperature and offspring phenotype has been conducted under constant incubation conditions, conditions that are quite different than those embryos would likely encounter in nature. We have conducted a series of fluctuating temperature studies using the painted turtle (Chrysemys picta) and the red-eared slider (Trachemys scripta), in both laboratory and field settings. From these studies, we found that traits including body size and coloration are affected by temperature fluctuations, as are measures of immune function under some circumstances. We also found that offspring sex is impacted by temperature fluctuations, with fluctuations producing a greater proportion of females in both species. While constant temperature studies have provided us with a wealth of information on the potential effects of temperature on phenotype, if we are to begin to understand the complex relationship between incubation temperature and offspring phenotype, it is imperative that we utilize more naturalistic incubation conditions. This becomes even more pressing as we contemplate the potential effects of global climate change on both mean temperatures and temperature fluctuations.