Bioacoustics of Modicogryllus (Modicogryllus) perplexus

Bioacoustics. The calling song of M. perplexus on Socotra consists of echemes lasting 400–450 ms and repeated at the rate of about 0.4–0.6 per second (Fig. 151 A ). Echemes consist of 22–25 syllables, repeated at 63–67 per second in the second two-thirds part, being slower and quieter in the first part (42–48 per second) (Fig. 151 B ). The carrier frequency is 5.6 kHz (5.5 kHz in the first few syllables) and has several harmonics at higher frequencies (Fig. 151 C ; XC 877950, accessible at https://www.xeno-canto.org/877950 ). Otte and Cade (1984) described the sound of specimens from South Africa as short trills consisting of two parts; the first third to two-thirds consists of a simple train of pulses; the second part consists of pairs of pulses. Deducing from the information in their publication, we would describe the calling song as consisting of echemes lasting 450–650 ms and repeated at about 0.8–1.4 per second. Echemes consist of about 32–36 syllables, repeated at 58–76 per second in the first part of the echeme up to 81–107 per second in the second part of the echeme and with 4–9 pairs of syllables (with a syllable repetition rate of 61–81 per second). The carrier frequency is 5.7–7.1 kHz. The song of Socotran specimens is similar to that of South African specimens. However, there are also apparent differences, for example, in the number of syllables in echemes and the presence of pairs of syllables. Further research is needed to explain these differences.