WITHIN-MALE VARIABILITY IN CALL PROPERTIES AND FEMALE PREFERENCE IN THE GREY TREEFROG

In nearly all female choice experiments with anurans, the values of ac oustic properties of experimental stimuli have been fixed. In nature, however, a female usually experiences an array of calls in which acous tic properties, especially dynamic ones, differ between males in varia bility as well as in mean values. High variability per se does not mak e a synthetic call more or less attractive to female grey treefrogs,Hy la versicolor, than a non-variable or low-variability call with about the same mean values of pulse number per call, call period, or both. F emales did prefer a low-variability alternative with a slightly higher number of sound pulses per unit time than the variable stimulus, sugg esting that females can resolve small differences in mean values betwe en the calls of different males despite considerable within-male varia bility. (C) 1995 The Association for the Study of Animal Behaviour