Meeting Abstract

53.1  Saturday, Jan. 5  Effects of estradiol on sexual motivation and preferences towards conspecific calls in female t�ngara frogs CHAKRABORTY, Mukta*; BURMEISTER, S.S; Univ. of North Carolina, Chapel Hill mukta@email.unc.edu

Sex steroid hormones influence reproductive behavior in most vertebrates. In t�ngara frogs, females use acoustic cues to choose mates. Males produce a simple �whine� call, and can add 1-7 �chucks� to make their calls more complex. Females prefer a whine with one chuck (W1C) over whines alone (W), but the effect of multiple chucks on female preferences is less clear. Prior studies show that estradiol (E2) is necessary and sufficient to induce phonotaxis toward calls. To assess the effects of E2 on call preferences, we compared naturally breeding females to E2-injected females in a series of choice tests. We caught females found in amplexus with males (n = 48), and measured their responses in the following five tests: 1) W vs. W1C; 2) W1C vs. heterospecific W; 3) W1C vs. W3C (W with three chucks); 4) W1C vs. W6C (W with six chucks); 5) W vs W1C. After testing, females were held in captivity for ten days during which time endogenous E2 declines. We then injected them with E2 (n= 33), or saline (S; n = 15). Twenty-four hours later, females were tested in the same five tests. We found that 85.4% of amplexed females were receptive, compared to 72.7% of E2-treated, and 40% of S-treated females. Amplexed females were also more responsive across tests compared to E2 and S-treated females, suggesting that amplexed females have higher sexual motivation. Among receptive females, amplexed and E2-treated females showed similar call preferences. In the first test, amplexed females chose W1C 82.9% of the time while E2-treated females chose the W1C call 79.2% of the time. Overall, receptive females chose W1C about 60% of the time over either W3C or W6C. Estradiol significantly increases phonotaxis behavior, and E2-treated females show the same call preferences as amplexed females.