WELCH, A.M.*; GERHARDT, H.C.; SEMLITSCH, R.D.; Univ. of North Carolina, Chapel Hill; Univ. of Missouri, Columbia; Univ. of Missouri, Columbia: Female preference strength and male call duration affect offspring fitness in gray tree frogs

Courtship displays can signal genetic quality, and the enhanced fitness of offspring sired by males with extreme displays can impose selection on female mating preferences. How selection acts on mating preferences depends on the relationship between female preferences and the benefits derived from preferred males. Thus, the maintenance of variation in female preferences is puzzling: if strong preferences for traits that signal high male quality are uniformly good, why does variation in preferences persist? Female gray tree frogs (Hyla versicolor) prefer a trait � long call duration � that has been shown to signal heritable genetic quality. However, females vary in preference strength, defined as the distance (simulated by call amplitude) from which they will approach a long call rather than a nearby short call. To test whether the genetic benefits of mating with long-call males depend on preference strength, we crossed long- and short-call males with strong- and weak-preference females. Offspring of long-call males metamorphosed sooner than offspring of short-call males, and this difference was more pronounced for offspring of strong-preference females. Offspring of long- and short-call males did not differ significantly in mass at metamorphosis, but offspring of strong-preference females were larger at metamorphosis than offspring of weak-preference females. Our results suggest that call duration and preference strength independently affect offspring quality, and that females with strong preferences may realize greater benefits of selecting a mate with long calls, the preferred trait.