Bioacoustics of Aphrodes bicincta

Male calling signals. Calling signal is a phrase lasting from 10–15 up to about 20 s and more, and consisting of two different parts ( Figs. 29 and 31–33 ): 1) a succession of partially merged pulses with very variable shape and repetition period; 2) more constant pattern consisting of alternating high- and low-amplitude syllables, the latter sometimes almost entirely reduced ( Figs. 34–38 ). Occasionally first part of a phrase is absent and signal includes only syllable succession ( Figs. 30 and 35 ). Male can produce single phrases or sing unceasingly for several minutes so that different parts alternate in a song without gaps. All components of signal have noise frequency spectra ( Fig. 39 ). No distinct differences were revealed between signals of males from European Russia ( Figs. 29 and 34 ) and Central Asia ( Figs. 30–33 and 35–38 ).