Meeting Abstract

P3.34  Monday, Jan. 6 15:30  How do yolk corticosterone and fluctuating incubation temperatures affect hatchling behavior and physiology? CARTER, AW*; ZIMMERMAN, LM; PAITZ, RT; BOWDEN, RM; Illinois State University ; Illinois State University ; University of Illinois; Illinois State University afwilso@ilstu.edu

The environment an organism experiences early in development can have profound and persistent effects on phenotype. In reptiles, both thermal and endocrine environments are influential in determining offspring phenotype. Using the red-eared slider (Trachemys scripta), we are exploring the effects of exposure to thermal fluctuations during incubation and maternal corticosterone on aspects of hatchling phenotype including physiology, morphology, and behavior. In the first study, we incubated eggs in a split-clutch design under three thermal flux regimes, all with the same average temperature and fluctuation amplitude during incubation. The incubation regimes only differed in their fluctuation frequency with a normal frequency (24 hr cycle), a hypo-flux (48 hr cycle), and a hyper-flux (12 hr cycle). While the hypo- and hyper- flux treatments may not directly reflect nest conditions readily observed in nature, they disentangle temperature and fluctuation effects on offspring phenotype. In the second study we dosed freshly laid eggs in a split-clutch design with corticosterone (0, 0.05, 0.15, 0.5 ng/ 5µl) and incubated eggs under a constant temperature. In both studies we are quantifying how these factors influence multiple ecologically important endpoints including morphology, sex, behavioral type (a suite of correlated behaviors across different contexts), and immunocompetence. Through these studies, we will be able to describe how incubation fluctuations, independent of temperature, as well as how corticosterone influence a variety of offspring traits and determine if these traits influence dispersal and survival in the field.