Meeting Abstract

1.3  Thursday, Jan. 3  Courtship in Xenopus tropicalis: Model Development for Evaluation of the Impact of Exposure to Endocrine Disrupting Compounds on Behavior SCHWENDIMAN, Angela L.*; SEARCY, Brian T.; PROPPER , Catherine R.; Northern Arizona University; Northern Arizona University; Northern Arizona University angela.schwendiman@nau.edu

This study characterizes mating behavior in Xenopus tropicalis. Six pairs of frogs were injected with either GnRH (25 ug/ml; 25 ul injected)or saline. Following injection frogs were placed in separate tanks continaing 4 liters of RO water with salts added back (housing medium) for 5 hours. To determine whether GnRH induces pheromonal communication, animals were placed in a y-maze and acclimating in the start box for five minutes. Each animal was given the choice of a control RO water arm or a treatment arm containing the water of the similarly treated animal of the opposite sex. Which arm the frog first chose and time spent in each arm was recorded. GnRH treated individuals chose members of the opposite sex over RO water more frequently than expected (binomial test, p=0.019). Control animals showed no preference (P=0.5). This result supports the hypothesis that GnRH induces pheromone production and/or detection. Subsequently, behavior was observed for 120 min, and then pairs were left over night. . Movement, distance apart, male and female approaches, male and female touches, male clasping the female, male arm waves, female arm waves, female rolls, egg deposition, and egg fertilization were recorded. The number of times injected females roll whether in amplexus or not is significantly different compared to controls (p=0.0285). GnRH treated pairs spent more time closer together than did controls (P= 0.009). More GnRH injected animals laid eggs than did controls (p=0.02). The results of this study indicate that specific parameters of X. tropicalis courtship may provide useful behavioral measures to determine how exposure to environmental contaminants results in behavioral changes ultimately affecting fitness.