Meeting Abstract
P2.93 Monday, Jan. 5 Nonlinear growth patterns in tadpoles based on parental call length WILLIAMS, A.S.*; GERHARDT, H.C.; WELCH, A.M.; University of Missouri; University of Missouri; College of Charleston, SC aswhx5@mizzou.edu
Females in many species prefer to mate with males bearing showier ornaments or more energetic displays. Yet, these preferences are not always linear: bigger is not always better. Female gray treefrogs (Hyla versicolor) show a nonlinear mating preference, strongly preferring males with long or medium call lengths, while avoiding males producing very short calls. According to the good genes hypothesis of sexual selection, females choose mates in order to obtain high quality genes for their offspring. Genes for high larval growth rates should help offspring to avoid environmental stresses and predation and should, therefore, provide a better chance to survive. We hypothesize that the nonlinear mating preference of female gray treefrogs reflects nonlinear benefits of mate choice. Specifically, we predict that the developmental rate of offspring mirrors the nonlinear preference function for call duration exhibited by females, in that the progeny of males producing long- and medium-length calls will develop more rapidly than the progeny of males producing short calls. To test these predictions, we used artificial fertilizations to cross twenty-seven males with long, medium, and short call lengths with six females. Five hundred and forty tadpoles were raised individually in the laboratory. During development, the tadpoles were subjected to high and low food treatments to test effects of environment on their development. We weighed the tadpoles at three weeks of age and at metamorphosis. Preliminary results indicate that progeny of short-duration callers grew better than progeny of long- and medium-length callers in both food treatments. Food treatment affected growth for progeny of all parental call lengths. The nonlinear growth function does not mirror that of the female preference.
