Chorthippus karelini (Uvarov)

Vedenina, Varvara, Tishechkin, Dmitry, Kovalyova, Evgenia & Sevastianov, Nikita, 2025, A new species of the subgenus Chorthippus Fieber, 1852 (Orthoptera: Acrididae: Gomphocerinae: Chorthippus) from Kazakhstan and Kyrgyzstan, closely related to C. angulatus Tarbinsky and C. karelini (Uvarov), Zootaxa 5653 (2), pp. 246-262 : 249-254

Chorthippus karelini (Uvarov)

Stenobothrus karelini Uvarov, 1910: 367–368 .

Material examined: Kazakhstan: 1 10 km SE of Aktobe , near Aktjubinsk reservoir, N 50°09.6’, E 57°18.8’, 25.06.2018, 4♂, leg. V . Vedenina & N. Sevastianov ( CV), song recordings in 4♂; 2 Pavlodar region, ab. 44 km SW of Pavlodar, environs of Pogranichnoe , N 52°05.4’, E 76°24.9’, 04.07.2019, 1♂, 1♀, leg. V . Vedenina, N. Sevastianov & T . Tarasova ( CV), song recording in 1♂; 3 Pavlodar region, between Terenkol’ and Beregovoe, near Irtysh River , N 53°05.1’, E 75°56.6’, 05.07.2019, 3♂, 3♀, ( CV), leg. V . Vedenina, N. Sevastianov & T . Tarasova, song recordings in 2♂; Petropavlovsk, 3.07.1929 ( ZMMU); 1♀, lake Balkhash, reed, 1.08.1935, 1♂, 1♀, leg. N. Djukov ( ZMMU); 4 Almaty region, ab. 60 km NE of Taldykorgan, near Kapal , N 45° 08.4’, E 79°01.3’, 1220 m a.s.l., 01.07.2016, 3♂, leg. V . Vedenina & T . Pushkar ( CV), song recordings in 2♂; 5 Jetisu region, Kerbulak district, Altyn-Emel pass, N 44°12.606’, E 78°30.392’, 1667 m a.s.l., 22.06.2023, 6♂, 1♀, leg. V . Vedenina, N. Sevastianov & T . Tarasova ( CV), song recordings in 2♂ ; Uzbekistan: Khumsan, Kazakst. 1300 m a.s.l., 9.08.1935, 1♂, leg. N. Troitzkii ( ZMMU) ; Turkmenistan: West Kopet-Dag, canyon Ai-Dere , 09.09.1966, 3 ♂, 2♀, leg. M. Chernjakhovsky ( ZMMU) ; Russia: Altai Krai, ab. 14 km NW of Byisk , N 52°39.1’, E 85°03.8’, 272 m a.s.l., 05.08.2017, 3♂, leg. V . Vedenina & N. Sevastianov ( CV); Altai Republic, Ongudai district, surr. of Kupchegen , N 50°37.144’, E 86°26.440’, 820 m. a.s.l., 08.08.2017, 1♀, leg. V . Vedenina & N. Sevastianov ( ZMMU); Altai Republic, Ongudai district, near Tuekta , N 50°50.7’, E 85°51.5’, 925 m a.s.l., 19.08.2021, 1♂, leg. N. Sevastianov, T . Tarasova & N. Ermilov ( ZMMU); Altai Republic, Ulagan district , ab. 13 km N of Aktash, N 50°25.854’, E 87°34.561’, 1903 m a.s.l., 06.08.2023, 1♂, 1♀, leg. V . Vedenina, N. Sevastianov & E. Kovalyova ( ZMMU); Altai Republic, Kosh-Agach district, surr. of Kyzyl-Tash , N 50°12.309’, E 87°56.780’, 1497 m a.s.l., 07.08.2023, 6♂, 2♀, leg. V . Vedenina, N. Sevastianov & E. Kovalyova ( ZMMU); 6 Altai Republic, Kosh-Agach district , ab. 9, 5 km SE of Zhana-Aul, N 49°46.165’, E 88°59.950’, 2013 m a.s.l., 08.08.2023, 3♂, 1♀, leg. V . Vedenina, N. Sevastianov & E. Kovalyova ( CV), song recordings in 3♂ .

Disribution. The species occurs very locally in Italy (as subspecies C. karelini bruttius Fontana & LaGreca, 1999 ), in the north-eastern part of Asia Minor, very locally in Ukraine (Kherson region, Askania-Nova), in the south-eastern part of European Russia, Transcaucasia, Kazakhstan, Middle Asia and Iran, eastward reaching Irkutsk region of Russia and north-western Mongolia ( Bey-Bienko & Mistshenko, 1951; Fontana & La Greca, 1999; Vedenina & Bukhvalova, 2001; Benediktov, 2005; Vedenina & Helversen, 2009; Vedenina et al., 2020; Gantigmaa & Myagmar, 2022). The northern border of the C. karelini range may overlap with the southern border of the C. albomarginatus range, where these species may hybridize ( Vedenina, 2015). C. albomarginatus inhabits northern and central Europe and northern Siberia, reaching Yakutia in the east. All sibling species of the C. albomarginatus group were shown to be vicarious ( Vedenina & Helversen, 2009). For example, C. albomarginatus does not occur in Kazakhstan, Middle Asia, or the southern Siberia, where it is replaced by C. karelini . We suggest, therefore, that C. albomarginatus can’t be found in Mongolia or China, and its records in these countries were erroneous (e.g., Zheng & Xia 1998; Gantigmaa & Myagmar 2022). By contrast, we expect to find C. karelini in both China and Mongolia.

Morphology. The males of C. karelini can be reliably distinguished from those of C. albomarginatus , C. angulatus and the new species by the number of stridulatory pegs and the peg position and density on the proximal third of the stridulatory file ( Fig. 4 ). The peg number in C. karelini varies from 140 to 188 in different populations, being higher than in other three species (Table). On the proximal third of the file in C. karelini , the pegs are arranged in two or even three rows ( Fig. 4 A ), in contrast to other three species, in which the pegs are organized in one row. The males of C. karelini can be also distinguished from those of C. angulatus and C. kegenicus by the highest ratio of tegmen length to distance from the tegmen base to bifurcation of M vein (Table, Fig. 5 A ). The females of C. karelini can be distinguished from those of C. angulatus and C. kegenicus by the structure of stridulatory file. In C. karelini (and also in C. albomarginatus ), stridulatory pegs are thin and resemble the bristle stumps ( Fig. 6 A, B ). Moreover, proximal edges of the sclerotized walls surrounding these stumps are noticeably elongated. By contrast, the pegs in the C. angulatus and C. kegenicus females resemble the well-developed male pegs ( Fig. 6 C, D ). Both sexes of C. karelini tend to have the longest tegmina (Table, Fig. 7 A, B ) in comparison to C. angulatus and the new species.

Calling song. As a rule, a male of C. karelini produces 3–4, rarely up to 8 echemes separated by intervals of 1.5–2.5 s ( Fig. 3 A–C ). Each echeme lasts for about 0.3–0.5 s. In the echeme beginning, the male vibrates with the two legs synchronously; during the main part of a song, the legs move alternately, each leg at a rate of about 45–60/s. Oscillographic analysis shows that a first loud pulse and several subsequent quiet pulses are sometimes separated from the following 20–25 pulses of a song by a pause. However, this feature may vary individually. The sound pulses of the main part of each song follow at a rate of 90–120/s.

The calling song of C. albomarginatus is very similar to that in C. karelini : the difference between these species lays mainly in the echeme duration (about 1.25 times more in C. albomarginatus than in C. karelini ) and pulse rate (about 1.25 times less in C. albomarginatus than in C. karelini ; Vedenina & Helversen, 2009). Such similarity in calling songs may prevent them from living together. On the other hand, the calling songs of the C. albomarginatus group substantially differ from the calling songs of C. angulatus and C. kegenicus ( Figs. 8 , 9 ). The calling echemes in both latter species last twice as long as in C. karelini . In C. angulatus , the two legs are moved much slower (22–40 /s) than in C. karelini , and the two legs are moved synchronously during the whole echeme. In C. kegenicus , the legs are moved at least three times slower than in C. angulatus , and this results to producing of 5–6 syllables per echeme.

Courtship song. The courtship song of C. karelini starts with alternation of two elements, which are repeated with the period of about 1 s ( Fig. 3 D–F ). When producing an element 1, the legs vibrate synchronously at the rate of about 10–11/s. When producing an element 2, the two hind legs vibrate with a phase shift at the rate of about 26–32/s. Oscillographic analysis shows that the syllables of the element 1 consist of the well pronounced pulses repeated at the rate of 21–24/s, whereas the syllables of the element 2 contain much more dense pulses following almost without gaps. The alternations of these two elements can last up to 2–3 min, followed by a complex of three more elements. An element 3 is similar to the element 2, but is remarkably longer, reaching 4–8 s in duration. Then comes a rather short (200–400 ms), element 4, which is produced by the low-amplitude synchronous leg vibrations at the rate of about 40–53/s. A subsequent element 5 is accompanied by two fast strokes of the legs ( Fig. 3 F ). A second stroke is accompanied with lifting of abdomen and produced with the tibiae; the maximal angle between tibia and femur is 30°. Both strokes are produced with synchronous movements of the two legs, but most of the element 5 is generated by alternate leg movements. The element 5 reminds the calling song of C. karelini . The complex of the elements 3, 4 and 5 is usually repeated 2–3 times, and then again followed by the alternation of the elements 1 and 2.

The courtship song of C. karelini strongly differs from the courtship songs of C. albomarginatus ( Vedenina & Helversen, 2009) , C. angulatus and C. kegenicus . In the two latter species, the courtship songs start with the small-amplitude movements of the hind legs, which generate short syllables repeated at the rate of about 3.5–6/s (element 1, Figs. 8 , 10 ). In about 0.2–1 min, there comes the elements 2 and 3; in contrast to the element 1, they are produced by rather complex leg movements. One of these elements remind the calling song of each species. However, the temporal structure of sound elements 2 and 3 is completely different from that in the C. karelini courtship, and the males of C. angulatus and C. kegenicus do not produce strokes with hind tibiae.

Figures

FIGURE 3. Oscillograms of the calling song (A–C) and the courtship song (D–F) in Chorthippus karelini from Kazakhstan (localities 1 and 5). Song recordings are presented at three different speeds (faster oscillograms of the indicated parts of the songs shown in B–C and E–F). 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, drawings show different positions of the hind legs and abdomen at the corresponding moments of the song.

FIGURE 4. Proximal part of the stridulatory file on inner side of hind femur: Chorthippus karelini male (A), female (B); C. albomarginatus male (C), female (D); C. angulatus male (E), female (F); C. kegenicus sp. nov. male (G), female (H). Scale 200 mkm.

FIGURE 5. Morphological differences between males of Chorthippus karelini (blue circles), C. angulatus (green triangles), and C. kegenicus (red squares). (A) peg number (ln) vs. ratio of tegmen length to distance between tegmen base and bifurcation of M vein; (B) ratio of prozona length to pronotum length vs. ratio of C+Sc areas width to R area width of tegmen.

FIGURE 6. Proximal and middle parts of the female stridulatory file on inner side of hind femur: Chorthippus karelini (A); C. albomarginatus (B); C. angulatus (C); C. kegenicus sp. nov. (D). Scale 100 mkm.

FIGURE 7. Tegmina of Chorthippus karelini male (A), female (B); C. angulatus male (C), female (D); C. kegenicus sp. nov., paratypes, male (E), female (F) and C. kegenicus sp. nov., paratypes, head and pronotum, dorsal view in male (G) and in female (H). Scale 2 mm.

FIGURE 8. Oscillograms of the calling song (A–C) and the courtship song (D–F) in Chorthippus angulatus from Kazakhstan (locality 8). Song recordings are presented at three different speeds (faster oscillograms of the indicated parts of the songs shown in B–C and E–F). 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, element 1 is presented in (E).

FIGURE 9. Oscillograms of the calling songs in Chorthippus kegenicus sp. nov. from Kazakhstan (locality 11) and Kyrgyzstan (locality 12). Song recordings are presented at three different speeds (faster oscillograms of the indicated parts of the songs shown in B–C and E–F). In all oscillograms the two upper lines are recordings of hind leg movements and the lower line is the sound recording.

FIGURE 10. Oscillograms of the courtship songs in Chorthippus kegenicus sp. nov. from Kazakhstan, locality 9 (A) and locality 10 (B). Song recordings are presented at two 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.