Fig. 1. Proportions of females choosing bimodal over unimodal alternatives. Numbers above symbols show the sample size (number of females responding). Circles, alternative to bimodal stimulus had only the high-frequency peak; squares, alternative to bimodal stimulus had only the low-frequency peak. SPLs equalized at 85 dB SPL except for tests of H. avivoca; the bimodal stimulus was 86 dB SPL and the single-peaked calls, 83 dB SPL (see the text for the rationale). Error bars are 95% credible intervals; if there is a single error bar, there was a significant (P<0.05) preference in a two-tailed binomial test. ^*Previously published data re-plotted (Gerhardt, 2005b); see text. NW, northwestern mtDNA lineage; E, eastern mtDNA lineage as defined by Ptacek et al. (Ptacek et al., 1994).