Phlepsius intricatus

15. Phlepsius intricatus (Herrich-Schäffer, 1838) Figs 64–68. MATERIAL. 1. The Lower Volga Region, Dosang Railway Station 60 km north of Astrakhan, Artemisia arenaria DC. in the desert, 29.VI.2010, signals of one male recorded at 29 °C. 2. Kyrgyzstan, Western Tien Shan Mts., the Naryn River Basin, Bekechal Gorge, 19 km southwest from Karakul Town, 41.536° N, 72.495° E, 3.VII.2023, signals of two males recorded at 36 °C. SIGNALS. The male calling signal consists of single or repeated phrases lasting for about 2.1– 2.6 s in the male from the Lower Volga Region and for 1.4– 2.1 s in males from Kyrgyzstan. If the male produces several phrases one after another, the gaps between them average from 2 up to 6–7 s in our recordings (Figs 64–65). The phrase consists of three sequences of pulses (Fig. 67). The initial and final sequences are identical, the middle, i. e., the second sequence differs from them in the shape of vibrations and, as a consequence, in the frequency spectrum (Fig. 66). In some signals, the first sequence is partially or entirely reduced. The pulse repetition period in the initial and final sequences is 10–12 ms at 29 °C and 7–8 ms at 35–36 °C. The pulse repetition period in the middle sequence is much longer and averages 20–22 and 15–20 ms, respectively. Often the pulses in the signal are poorly distinguishable (Fig. 68). REMARKS. The distance between recording sites is approximately 2030 km, however, the signals of males from different populations are almost identical. The slight differences between them in temporal parameters are due to differences in temperature during recording. A remarkable feature of signals of P. intricatus is that signal parts similar in the temporal pattern (Fig. 68) distinctly differ in frequency spectra (Figs 65–66).