Stenobothrus miramae Dirsh 1931

Stenobothrus miramae Dirsh, 1931

Distribution. South-eastern part of European Russia, Crimea, western Kazakhstan.

Material. 16. Russia, Orenburg region, ab. 20 km NW of Orsk, environs of railway station Guberlja, 51°17.2’ N, 58°10.6’ E, 29.06.2018, song recordings in 5 ³.

References to song. Waeber, 1989: recordings S. nigrogeniculatus Kr. from Asia Minor, calling song; Bukhvalova & Vedenina, 1998: recordings from Crimea and Russia (Orenburg region), calling song; Tishechkin & Bukhvalova, 2009b: recordings from Crimea, calling song; Berger, 2008: recordings of S. nigrogeniculatus Kr. from Asia Minor, calling and courtship songs.

Song. The courtship song of S. miramae (Fig. 7) contains no elements similar to the calling song. The element 1 of the courtship song is produced by the low-amplitude leg movements generating syllables repeated at the rate of about 1–1.5/s (Fig. 7 F). Each syllable lasting for about 200–250 ms is usually composed of approximately 20 pulses, repeated at the rate of about 95–105/s. In 4.5–7 s, the element 2 follows, lasting 6–8 s and generated by incredibly complex leg movements. The leg-movement analysis reveals about 5-8 long syllables repeated at the rate of about 0.6–0.7/s. One leg is moved up reaching the highest position, then it is moved down, and next it is slightly lifted and kept in intermediate position; in about 400 ms, the leg is moved down and then up, but the amplitude of these movements is lower than during the previous up and down movements (Fig. 7 G). Thereupon the leg is again kept in intermediate position, until the leg is moved up into the highest position. Superimposed on these slow movements are the small-amplitude vibrations of about 90–100/s. Another leg can be moved in about similar pattern but shifted in phase by half a period, or another leg can be moved in a completely different pattern, which can be interpreted as a mirror reflection of the first leg movement, and also with the phase shift (Fig. 7 H). The oscillographic analysis of the sound shows continuous series of pulses of varying amplitude repeated at the rate of about 90–100/s. The elements 1 and 2 are usually alternated for more than 2 min, and are finally followed by the element 3 (Fig. 7 E, I). A male sitting in front of a female hits the female several times with the head (Fig. 8 A). Then the male slowly raises both hind femora through an angle of more than 90° so that the knees appear to be over his head (Fig. 8 B) and keep them in this position for about 5–20 s. The frequency spectra of the elements 1 and 2 have many dominant peaks between 10 and 30 kHz, but one peak around 26 kHz is maximal on the spectrum of the element 2 (Fig. 7 C, D).

Comparative remarks. The courtship song of S. miramae is shown for the first time. However, it is almost identical to the courtship song of S. nigrogeniculatus Kr. (Berger, 2008). Taking into account the similarity in the calling songs between these species (e. g. Bukhvalova & Vedenina, 1998; Berger, 2008), one could suggest a synonymy of these species. According to Berger (2008), S. nigrogeniculatus has unusual history. This species was described by Krauss in 1878 from Dalmatia but afterwards, it was only recorded from Turkey. In all further works (e. g. Bei-Bienko & Mistshenko, 1951; Karabag, 1958; Demirsoy, 1977) the Turkish specimens were named under S. nigrogeniculatus, but they are suggested by Berger (2008) to be different in morphology and song from the animals described by Krauss. Thus, further taxonomic studies are necessary to solve the problem of the synonymy in this group.