Chorthippus angulatus Tarbinsky 1927

Chorthippus angulatus Tarbinsky, 1927

Distribution. Southern and south-eastern Kazakhstan, Middle Asia.

Material. 11. Kazakhstan, Almaty region, between Saryozek and Zharkent, environs of Basshi, along stream. 44° 10.1’ N, 78° 45.1’ E. 05.07.2016. Song recordings in 2 ³.

References to song. Bukhvalova & Vedenina, 1998: recordings from Kazakhstan, calling song.

Song. The courtship song of Ch. angulatus is completely different than the calling song. The courtship song starts with the small-amplitude movements of the hind legs, which generate short syllables repeated at the rate of about 5/s (element 1, Fig. 14 A, C). The syllables contain 3–4 pulses of variable amplitude, which are only produced during synchronous down leg-movements. In about 0.5–1 min, there comes the element 2; in contrast to the element 1, it is produced by rather complex leg movements. Each leg alternate low- and high-amplitude movements at the rate of about 2.5–3.5/s, and superimposed on these slow movements are small-amplitude vibrations of 20–30/s (Fig. 14 D, F). The two legs are moved alternately, so that one leg produces the high-amplitude stroke, whereas the other leg produces the low-amplitude stroke. During the slow up movements of the legs, a loud pulse of longer duration is generated; during the slow down movements, several (2–4) short, quieter pulses are produced. The pulses of longer duration are repeated at the rate of about 5-6/s. The element 2 lasting from 3 to 15 s is followed by the element 3. It starts with the high-amplitude stroke of one leg and the low-amplitude stroke of another leg, similarly to those of the element 2 (Fig. 14 E). However, there follow synchronous vibrations of both legs repeated at the rate of about 20–30/s and lasting about 800 ms– 1.5 s. The next high-amplitude stroke is generated by another leg. During the high-amplitude stroke, the loud, long pulse is produced; then follows a series of short pulses repeated at the rate of about 25/s. Sometimes, the element 3 can alternate with the element 2 for more than 1 min (Fig. 14 B). The frequency spectra of all elements lie in the band of 6–25 kHz with two peaks at 12 and 23 kHz (Fig. 14 G, H).

Comparative remarks. The courtship song of Ch. angulatus has been presented for the first time.