High speed video observations at 1250 frames per second show that each calling song corresponds to only one FW closure (i.e. one syllable), the gaps within the syllables are made by the jerking closing movement of the FWs. At 20°C, these mono-syllabic calling songs are emitted in irregular groups of 7–12 (m = 10.6 ± 2.2, n = 5) that lasts for 77 ± 13 s with a period of 208 +/- 50 s. Each syllable shows an indented temporal profile due to the jerking FW closures, with the following characteristics: syllable duration = 48 ± 2 ms; syllable period (within the echemes / syllable groups) = 8.0 ± 2.3 s; syllable duty cycle = 0.65 %. The dominant frequency is 13.28 ± 0.22 kHz and corresponds to the third frequency peak of the song, with a clear harmonic series. [1]
