Analysis of the frequency spectra in calling and courtship songs, and body-size effects in <i>G</i>. <i>bimaculatus</i>.

<p><b><i>(A)</i></b><i>Upper panel</i>. The spectrogram of the calling song from a representative male. The vertical axis shows the frequency in kHz, and the horizontal axis shows the time in seconds. The color indicates the energy of each frequency component in dB (dBFS, decibels relative to full scale). The color scale is shown in the right panel. <i>Lower panel</i>. An oscillogram of the calling song from the representative male corresponding to the above spectrogram. The vertical axis shows the sound amplitude, and the horizontal axis shows the time [s]. (B) Distribution of the frequency component of calling songs (n = 50). The vertical axis shows the density, and the horizontal axis shows the frequency (kHz). The histogram (gray) and distribution curve from the kernel density estimate (magenta). The distribution curve shows a single peak at 5.7 kHz. The frequency band analyzed in the following experiment (Fig 1C) is indicated in orange. (C) Evaluation of the body-size effect on the dominant frequency of the calling song. The dominant frequency of the 2-s calling song was calculated for each male (n = 50) and plotted against the individual body mass. The vertical axis shows the dominant frequency (kHz), and the horizontal axis shows the body mass (mg). The background color of the band corresponds to the orange band shown in Fig 1B. No significant effect was detected (p = 0.572). Statistical information is summarized in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0146999#pone.0146999.t001" target="_blank">Table 1</a>. The significance level was adjusted by Bonferroni correction. (D) <i>Upper panel</i>. The spectrogram of the courtship song from a representative male. The vertical axis shows the frequency in kHz, and the horizontal axis shows the time in seconds. The color indicates the energy of each frequency component in dB (dBFS, decibels relative to full scale). The color scale is shown on the right panel. <i>Lower panel</i>. An oscillogram of the courtship song from the representative male corresponding to the above spectrogram. The vertical axis shows the sound amplitude, and the horizontal axis shows the time [s]. (E) Distribution of the frequency component of courtship songs (n = 53). The vertical axis shows the density, and the horizontal axis shows the frequency (kHz). The histogram (gray) and distribution curve from the kernel density estimate (magenta). The distribution curve shows two peaks at 5.8 and 14.7 kHz. The frequency bands analyzed in the following experiment (Fig 1C) are indicated in green or in blue. (F) Evaluation of the body-size effect on the dominant frequency of the courtship song. The dominant frequency of the 2-s courtship song was calculated for each male (n = 53) and plotted against the individual body mass. The vertical axis shows the dominant frequency (kHz), and the horizontal axis shows the body mass (mg). Each background color of the band corresponds to the green or blue band shown in Fig 1E. No significant effect was detected (p = 0.241 for lower band, p = 0.042 for higher band). Statistical information is summarized in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0146999#pone.0146999.t001" target="_blank">Table 1</a>. The significance level was adjusted by Bonferroni correction.