Bioacoustics of Viriacca viridis

Calling song (2♁, 30.4°C) ( Fig. 12 ). The calling song consists of echemes that can vary in duration (1.1–20.9 s) and sometimes extend to become a continuous trill. A short echeme, on average, has a duration of 3.4 s. Each echeme commences with syllables with increasing amplitudes until a maximum. At times, the echeme is truncated by short pause. The syllable duration is 19.4±0.9 ms (17.6–21.7 ms) and the interval between consecutive syllables is 12.8±1.1 ms (10.4–15.7 ms). The syllable repetition rate is 31±1 syllables s−1 (29–33 syllables s−1 ). The call spectrum is broad-based and has a peak frequency of 26.4±1.1 kHz (24.5–28.8 kHz). The calling song of Viriacca viridis has a similar structure (i.e., echemes that can become continuous trills) as those of Viriacca insularis Gorochov, 2011 from Pulau Tioman ( Pahang ) and Viriacca modesta Gorochov, 2013 from Borneo ( Tan et al ., 2023 ). The call spectrum does not differ, ranging from 21.5–28.8 kHz. However, the syllable repetition rate is slightly lower than that of V. modesta (average 34 syllables s−1 ) and higher than that of V. insularis (average 22 syllables s−1 ).