Variation in Male Advertisement Calls in the Neotropical Frog Physalaemus enesefae

Abstract

I described the advertisement call of Physalaemus enesefae in the time and spectral domains and analyzed the relationship between male body size, mass and condition, and call characteristics. I also estimated among-male and within-male variation in seven call traits and their repeatabilities. For the population under study, male calls were 720 ms long, had a dominant frequency of 898 Hz, and were repeated at 3.8-sec intervals, on average. Weak but significant correlations existed between male mass and three call traits: dominant frequency, initial frequency, and final frequency of the call. There was ample among-male variation in all call traits analyzed. In relation to within-male variation, the intercall interval had the highest coefficients of variation, and the initial and the final frequency of the call had the lowest. All the call traits analyzed were static except for intercall interval, which was dynamic. Intercall interval had the lowest repeatability of all call traits analyzed. Thus, call traits with the lowest within-male variation had the highest repeatabilities and vice versa. Individual variation in call traits and high repeatabilities set the stage for the evolution of most call traits. Selection on intercall interval, however, might have a limited evolutionary effect as a consequence of its low repeatability.