Omocestus haemorrhoidalis (Charpentier, 1825)

Vedenina, Varvara, Sevastianov, Nikita & Tarasova, Tatiana, 2020, Contributions to the study of the grasshopper (Orthoptera: Acrididae Gomphocerinae) courtship songs from Kazakhstan and adjacent territories, Zootaxa 4895 (4), pp. 505-527 : 509-511

Omocestus haemorrhoidalis (Charpentier, 1825)

Distribution. Transpalaearctic.

Material. Kazakhstan: 4. Akmola region, ab. 40 km NW of Ereimentau, steppe near Baysary, 51°59.3’ N, 72°42.1’ E, 03.07.2019, song recordings in 1 ³; 8. Pavlodar region , Zhelezinsky district , environs of Pyatiryzhsk , 53°22.4’ N, 75°33.6’ E, 05.07.2019, song recordings in 2 ³; 10 . Almaty region, environs of Kapal , 43° 08.4’ N, 79° 01.3’ E, 1220 m a.s.l., 01.07.2016, song recording in 1 ³; 12 . Almaty region, ab. 6 km SW of Zharkent , pasture near fruit gardens, 44° 08.4’ N, 79° 55.3’ E, 06.07.2016, song recording in 1 ³; 13 . Almaty region, ab. 4 km SE of Kegen, flood-lands of Kegen river , 42° 59.6’ N, 79° 16.5’ E, 07.07.2016, song recording in 1 ³ . Russia: 14. Orenburg region, ab. 10 km W of Novosergievka, 52° 01.2’ N, 53° 42.0’ E, 13.07.2012, song recordings in 3 ³; 15. ab. 10 km E of Orenburg, near Ural river , 51º44.3’ N, 55º20.8’ E, 13– 14.07.2012, song recordings in 2 ³ .

References to song. Faber, 1953: verbal description only, calling and courtship songs; Waeber, 1989: recordings from Spain and Turkey, calling song; Ragge & Reynolds, 1998: recordings from France, calling song; Savitsky, 2005, 2009: recordings from Russia (Volgograd and Astrakhan’ regions), calling and courtship songs; Tishechkin & Bukhvalova, 2009a, b: recordings from Russia (Saratov region, Eastern Siberia, and Primorskiy Kray), calling song; Tishechkin, 2017: recordings from Kyrgyzstan, calling song; Willemse et al., 2018: recordings from Greece, calling song.

Song. The courtship song ( Fig. 3 ) starts with producing a single syllable of distinct pulses lasting about 100 ms (element 1, Fig. 3 B ). This syllable is generated by synchronous down movements of both hind legs in a stepwise manner. The element 1 is immediately followed by an echeme similar to the calling song (element 2). It lasts about 3–4 s and consists of syllables repeated at the rate of about 25–30/s. The element 2 is also produced by almost synchronous leg movements. During calling, a male typically produces one echeme, whereas the courting male can emit many echemes containing both elements with the intervals varying in the range of about 8–20 s. In the developed courtship, one can distinguish the element 3 in the leg-movement pattern. After the element 2, the male raises both legs and produces similar up and down movements as before, which generate much quieter sound ( Fig. 3 C ). Then the legs are moved down and start to move in antiphase at the rate of about 10–13/s. During the element 3 that lasts about 1.4–2 s, the legs produce the low-amplitude pulses at the rate of about 22-25/s. The rate of these pulses is twice as high as the rate of the leg movements. The three elements are repeated from two to three times, followed by an attempt to copulate with a female ( Fig. 3 A ). The frequency spectra of the first and the second sound elements are broad and rather similar, but the dominant frequencies are much higher than in O. viridulus , with two maxima at around 22–25 kHz and 38–40 kHz.

Comparative remarks. Despite O. haemorrhoidalis often attracts the attention of bioacoustics, the courtship song of this species has been poorly studied. Savitsky (2005) describes courtship behaviour in one male from Astrakhan’ region. The courtship song of this specimen includes two more elements that follow after the main echeme of the calling song type (element 2). These two elements, however, are completely different from those found in the courtship songs of our specimens from Orenburg region and Kazakhstan. According to the verbal description of Faber (1953), the courting males from Germany produce elements 1 and 2, but don’t produce the element 3. Faber (1953) also mentions the difference in amplitude of movements between the two legs similarly to that we show in O. viridulus ( Fig. 2 C, E ). We, however, don’t find the difference in the leg-movement amplitude in our specimens of O. haemorrhoidalis .

Figures

FIGURE 2. Oscillograms and frequency spectra of the courtship songs of two males (A, B) of Omocestus viridulus from Altai Republic. Song recordings are presented at three different speeds (faster oscillograms of the indicated parts of the songs shown in C–E). In all oscillograms the two upper lines are recordings of hind leg movements and the lower line is the sound recording. Different elements of the courtship song are indicated by numbers 1–4. Frequency spectra shown for the elements 1 (F) and 3 (G).

FIGURE 3. Oscillograms (A-D) and frequency spectra (E-F) of the courtship song of Omocestus haemorrhoidalis from Orenburg region. Song recordings are presented at three different speeds (faster oscillograms of the indicated parts of the songs shown in B–D). In all oscillograms the two upper lines are recordings of hind leg movements and the lower line is the sound recording. Different elements of the courtship song are indicated by numbers 1–3. Frequency spectra shown for the elements 1 (E) and 2 (F).