Meeting Abstract
P2.2 Monday, Jan. 5 Phenotypic and genetic variation in season-long calling performance in gray treefrogs HUMFELD, S.C.*; WELCH, A.M.; SMITH, M.J.; GERHARDT, H.C.; Univ. of Missouri, Columbia; College of Charleston, SC; Arthur Rylah Institute, Victoria, AU; Univ. of Missouri, Columbia HumfeldS@missouri.edu
Sexually-selected traits are often costly to produce or maintain. Because of these costs, investment in sexual attractiveness may come at the expense of survival or energetic allocation to other aspects of reproductive effort. These costs may therefore lead to life-history tradeoffs between current reproductive effort and residual reproductive value. As a result of such tradeoffs, snapshot measures of sexually-selected traits may be inadequate to understand the strength and direction of selection acting on secondary sexual characteristics. This issue is particularly salient in species with extended breeding seasons; for example, previous studies of anurans with extended breeding seasons suggest that the number of nights during which an individual participates in a breeding chorus is a stronger predictor of mating success than are values of particular advertisement call characteristics. In gray treefrogs, males produce an energetically expensive acoustic advertisement signal, the length of which affects its attractiveness to females. In order to understand how allocation to various aspects of reproductive effort influences selection on male mating displays, we are testing for phenotypic and genetic correlations among call characteristics, nightly calling effort, chorus participation and season-long calling effort. We measured these variables over a two-month period from a group of nearly 200 captive male gray treefrogs (Hyla versicolor) resulting from artificial crosses. Frogs were housed individually in an outdoor array, and each cage was fitted with a microphone which continually sampled calls over the two-month period. We will present preliminary results of calling behavior from these long-term measurements.
