Chorthippus maritimus Mistshenko, 1951

Tarasova, Tatiana, Tishechkin, Dmitry & Vedenina, Varvara, 2021, Songs and morphology in three species of the Chorthippus biguttulus group (Orthoptera, Acrididae, Gomphocerinae) in Russia and adjacent countries, ZooKeys 1073, pp. 21-53 : 21

Chorthippus maritimus Mistshenko

Chorthippus miramae Ramme, 1939: 131, nomen nudum.

Chorthippus meridionalis Mistshenko, 1950: 790.

Chorthippus biguttulus maritimus Mistshenko, 1951: 514.

Chorthippus miramae Ramme, 1951: 389.

Chorthippus biguttulus eximius Mistshenko, 1951: 515, syn. n.

Chorthippus bornhalmi Harz, 1971: 336, syn. n.

Chorthippus miramaellus Woznessenskij, 1996: 204.

Chorthippus sinuatus Mistshenko et Woznessenskij, 1996: 204.

Material examined.

Bulgaria: 4 Sofia region, lake Iskyr , 29.VI.2002, 6 ♂ 5 ♀, leg. V. Vedenina (ZMMU); 5 Vraca region, ab. 3 km S of Vraca, Vracniki Balekan National Park, Memorial Botev , 30.VI.2002, 2 ♂, leg. V. Vedenina (CV) ; Greece: 2 Phthiotis, environs of Timfristos, NE slope, 27.V.1998, 1 ♂, leg. V. Vedenina (CV); 3 Phthiotis, ab 40 km NW Lamia environs of Lautra Kaitsas , 26.V.1998, 3 ♂ 1 ♀, leg. V. Vedenina (CV); 6 Macedonia, Drama, Mt Falakro above Volakas , 5 km NE Elatia, 24.VII.2004, 1 ♂, leg. V. Vedenina, song recordings in 2 ♂ (CV); 7 Macedonia, Drama, W. Rodopi , 5 km NE Elatia, 23.VII.2004, 1 ♂ 1 ♀, leg. V. Vedenina (CV) ; Ukraine: 15 Odessa region, near Sychavka , 03.VII.1997, 5 ♂, leg. V. Vedenina (ZMMU); 17 Kirovograd region, Novoukrainka district, environs of Pomoshnaya , 26.VI.1997, 2 ♂, leg. V. Vedenina, song recordings in 2 ♂ (CV); 21 Kherson region, Chernomorsky nature reserve, Solyonoozerny area , 25.VII-05.VIII.1995, 2 ♂ 1 ♀, leg. V. Vedenina (CV); 23 Crimea, Bakhchisaray district , 3-4 km E of Gluboky Yar, 11.VI.1997, 4 ♂, leg. D. Tishechkin, song recordings in 4 ♂ (ZMMU); 24 Crimea, Simferopol’ district, environs of Pereval’noe, 20.VI.1997, 3 ♂, leg. D. Tishechkin, song recordings in 3 ♂ (ZMMU); 25 Dnipro region , Pavlograd district , Samara reserve , 12-15.VII.1996, 6 ♂, leg. V. Vedenina (CV); 26 Crimea, Kerch peninsula, E shore of Kazantip bay, environs of cape Chagany , 26.VI.1997, 1 ♂, leg. D. Tishechkin, song recordings in 1 ♂ (ZMMU); 27 Kharkov region, Izjum district, Kamyshevacha , 15.VII.1996, 5 ♂ 1 ♀, leg. V. Vedenina (ZMMU); 28 Kharkov region, Izjum, Kremenetz hill, 15.VII.1996, 1 ♂, leg. V. Vedenina (CV); Abkhazia: 34 Sukhumi region , slopes near highway Sukhumi - Gagra, 21-22.X.2005, 5 ♂ 5 ♀, leg. V. Vedenina, song recordings in 3 ♂ (ZMMU) ; Russia: 33 Krasnodarsky krai, near highway Krasnaya Poljana - Adler , 22.X.2005, 4 ♂ 3 ♀, leg. V. Vedenina, song recordings in 4 ♂ (CV); 39 Saratov, slopes near Polivanovka , 28.VI.2020, 2 ♂, leg. V. Vedenina, song recordings in 2 ♂ (CV); 41 Saratov region, Krasnokutsk district , near D’yakovka, 28.VI.2020, 6 ♂ 1 ♀, leg., song recordings in 5 ♂ (CV); 43 Saratov region, SW from Khvalynsk, environs of Ul'yanino village , 19.VII.2005, 3 ♂, leg. D. Tishechkin, song recordings in 3 ♂ (ZMMU); 44 Saratov region, ab. 6 km NW of Ershov , 22.VI.2018, 3 ♂, leg. V. Vedenina (CV); 45 Saratov region, 15 km NE Ozinki , 23.VI.1996, 4 ♂, leg. D. Tishechkin, song recordings in 4 ♂ (ZMMU); 42 Krasnoyarsk region, Astrakhan‘ district, environs of Dosang railway station, 03.VII.2000, 1 ♂, leg. D. Tishechkin, song recordings in 1 ♂ (ZMMU); 75 Irkutsk region, Olkhon district, 20 km from Jelantsy to strait Olkhonskie vorota, 15.VII.2003, 4 ♂, leg. D. Tishechkin, song recordings in 4 ♂ (ZMMU); 77 Buryatia, Barguzin valley, Ina river, 4 - 5 km downstream from Ina, 17.VII.2007, 3 ♂, leg. D. Tishechkin, song recordings in 2 ♂ (ZMMU); 78 Chita region , Klichka range, ab. 15 km W Klichka , 22.VII.2003, 2 ♂, leg. D. Tishechkin, song recordings in 1 ♂ (ZMMU); 79 Amur region, 15 km S Svobodny, environs of Malaya Sazanka , 05.VII.1995, 4 ♂, leg. D. Tishechkin, song recordings in 4 ♂ (ZMMU); 80 Primorskiy kray, Pogranichny district, environs of Barabash-Levada , 20.VII.1995, 3 ♂, leg. D. Tishechkin, song recordings in 3 ♂ (ZMMU); 81 Primorskiy kray, Pogranichny district, Khanka lake , 15 km S Turiy Rog, 21.VII.2006, 3 ♂, leg. D. Tishechkin, song recordings in 3 ♂ (ZMMU); 82 Southern Sakhalin, environs of Sokol , 02.VIII.2015, 4 ♂, leg. D. Tishechkin, song recordings in 3 ♂ (ZMMU) ; Kazakhstan: 62 Almaty region, 40 km N from Almaty, environs of Kara-Oi village, 12.VI.2017, 1 ♂, leg. D. Tishechkin, song recordings in 1 ♂ (ZMMU); 63 Almaty, botanical garden, 07.VII.1994, 3 ♂, leg. D. Tishechkin, song recordings in 3 ♂ (ZMMU); 65 Almaty region, ab. 20 km NE of Taldykorgan , 02.VII.2016, 4 ♂, 1 ♀, leg. V. Vedenina & T. Pushkar, song recordings in 1 ♂ (CV); 66 Kazakhstan , Almaty region, near Kapal , 01.VII.2016, 1 ♂, leg. V. Vedenina & T. Pushkar, song recordings in 1 ♂ (CV); 67 Kazakhstan , Almaty region, ab. 2.5 km W of Kapal, 02.VII.2016, 4 ♂ 4 ♀, leg. V. Vedenina & T. Pushkar, song recordings in 2 ♂ (ZMMU); 68 Urzhar region, 27 km SSE Taskesken, 5.5 km NW Karakol , 24.VI.2019, 1 ♂, leg. D. Tishechkin, song recordings in 1 ♂ (ZMMU) ; Turkmenistan: 49 Ahal region, Kaka district , 6-7 km S of Dushak, 14.V.2014, 3 ♂, leg. D. Tishechkin, song recordings in 3 ♂ (ZMMU) ; Kyrgyzstan: 51 Batken region, Leilek district, Turkestan range, 12 km S from Katran village , 11.VII.2014, 1 ♂, leg. D. Tishechkin, song recordings in 1 ♂ (ZMMU); 53 Batken region , N shore of Tortkul’skoye reservoir, 12 km WSW Batken, 09.VII.2014, 1 ♂, leg. D. Tishechkin, song recordings in 1 ♂ (ZMMU); 54 Jalal-Abad region , Chatkal range, Sary-Chelek nature reserve , environs of Arkyt, 22.VII.2008, 2 ♂, leg. D. Tishechkin, song recordings in 1 ♂ (ZMMU); 57 Chuy region , Jayyl district , Karakol river , 10 km upstream from confluence with Suusamyr, 07.VII.2016, 1 ♂, leg. D. Tishechkin, song recordings in 1 ♂ (ZMMU); 58 Chuy region , Djumgal river , between Baizak and Chaek, 30.VI.2014, 1 ♂, leg. D. Tishechkin, song recordings in 1 ♂ (ZMMU); 64 Issyk-Kul' region , Tossor river , 18 km E from Kadji-Sai, 15.VII.2013, 1 ♂, leg. D. Tishechkin, song recordings in 1 ♂ (ZMMU) .

Distribution.

(Fig. 1 ). C. maritimus is a widespread trans-Palearctic species. It includes C. bornhalmi from the Balkans and Anatolia ( Willemse et al. 2009; Sirin et al. 2010; Skejo et al. 2018) and as C. biguttulus eximius from Sukhumi, Abkhazia ( Mistshenko 1901). It also occurs in Moldova and southern Ukraine ( Heller et al. 1998). In the territory of Russia, its range stretches from Krasnodarsky krai to Sakhalin along the southern border. This species also occurs in Caucasus, southern Kazakhstan, Turkmenistan, very likely Uzbekistan, Kyrgyzstan, Mongolia, northern-east China, Korea and Japan ( Storozhenko 2002). The ranges of C. maritimus and C. brunneus overlap in Eastern Europe, Ukraine and the south-eastern part of European Russia. Moreover, C. maritimus and C. brunneus often occur syntopically. The range of C. maritimus also overlaps with the range of C. miramae in the south-eastern part of European Russia and in surroundings of the Baikal Lake, however, they do not occur in the same biotopes.

Recognition.

(Table 1 , Fig. 3 ). The males of C. maritimus can be distinguished from the males of C. brunneus by the longer stridulatory file (Fig. 3A ) and the higher number of stridulatory pegs (see Description). These characters are also mentioned as the distinguishing features between C. brunneus and C. bornhalmi by other authors ( Willemse et al. 2009; Skejo and Ivcovic 2015). The length of stridulatory file in C. maritimus is intermediate between those in C. miramae and C. brunneus . Both sexes of C. maritimus also tend to have the longest fore wings and pronotum in comparison with C. miramae and C. brunneus (Table 1 ). C. maritimus can be also distinguished from other species of the Chorthippus biguttulus group by the narrower costal area of fore wing. By contrast, C. maritimus differs from C. mollis by the wider costal area of fore wing and by the lower density of stridulatory pegs ( Bukhvalova 1993; Oliger 1974). C. bornhalmi and C. biguttulus eximius are not different in morphology from C. maritimus from Ukraine and Russia.

Description.

(Table 1 , Fig. 3 ). The head structure as in genus. Ratio length of vertical diameter of eye to maximum length of foveolae 2.8-3.4 in ♂, 3.0-3.2 in ♀; ratio minimum interocular distance to length of subocular groove 0.6-0.8 in ♂, 0.7-0.9 in ♀. Antennae filiform. Prozona is slightly shorter than metazona; median carina is distinct and continuous. Lateral pronotal keels are distinctly incurved, ratio between minimum and maximum widths 2.3-2.6 in ♂, 2.3-2.9 in ♀. In western populations keels are more angled, min/max width ratio up to 3.0. Tympanal aperture slit-like, 2.3-2.8 times in ♂, 2.6-2.8 in ♀ as long as broad. Fore and hind wings well developed in both sexes, wings far surpassing the apices of the hind knee. Costal area of fore wing has maximum width in the middle part or in the last third of the wing. Subcostal area narrow, its width 0.25-0.3 mm in ♂, 0.15-0.2 mm in ♀ (measured on the line of maximal width of costal area). Ratio width of fore wing to C & Sc areas 3.1-3.5 in ♂, 4.4-4.7 in ♀. Apical constriction (distance from C and Sc confluence to the wing tip) prolonged, ratio length of apical constriction to the wing length 3.3-3.8 in ♂, 3.5-3.8 in ♀. Stigma far from the wing tip, ratio length between stigma center and the wing tip to the wing length 2.4-2.7 in ♂, 2.3-2.5 in ♀. Hind femur gracile, ratio femur length to maximum width 4.4-4.6 in ♂, 4.4-4.7 in ♀. Stridulatory file consists of one row, its length nearly equal to the distance between last peg and tip of hind knee. The number of stridulatory pegs 100-168 in ♂, 104-157 in ♀. Body coloration varies from light straw to dark brown, sometimes with a red tone. The ventral side of the body lighter than dorsal side, and densely pubescent. Fore wings smoky, with a few dark spots in M area. Hind wings transparent at the base and slightly smoky in apical part, distal half of C area smoky or brownish. Hind femur in the inner side with black lengthwise line. Hind knees dark brown or blackish, particularly on upper lobe. Hind tibiae orange or reddish.

Measurements in mm. Body length: 15-18 in ♂, 19-26 in ♀, pronotum length: 3.1-3.4 in ♂, 4.1-4.4 in ♀, fore wing length: 14.1-15.5 in ♂, in 17.2-18.5 in ♀, fore wing width 3.1-3.4 in ♂, 3.2-3.5 in ♀, hind femur length: 9.8-10.6 in ♂, 12.8-14.1 in ♀.

Calling song

(Table 3 , Figs 5 , 6 ). The calling song of C. maritimus usually contains one to several echemes of median duration ranged from 1 to 4 s. In some populations (49, 62, 63), however, the median echeme duration is higher, ranging between 5-11.1 s (Table 3 , Fig. 5C ). The echeme rate also greatly varies between different populations (0.05-0.42 / s). The number of syllables per echeme varies in the range of 15 to 40, in populations with prolonged echemes - in the range from 40 to 70. The syllable duration is relatively stable within the same population; however, its median duration can vary between the populations in the range of 86-162 ms (Fig. 5D ). At the beginning of each echeme, the sound is very soft, but then it reaches maximum loudness after the first third of the echeme duration, being constant until the echeme end (Fig. 6D ). The syllables are generated by the leg movements with a small phase shift, which comprise the straight upstroke and stepwise downstroke (Fig. 6E, F ). Both upstroke and downstroke have the similar duration. The leg upstroke generates a noisy sound with unclear structure and slightly increasing amplitude; the stepwise downstroke generates 4-5 distinct pulses. The pulses, however, can be sometimes fuzzy. The durations and rates of echeme and syllable in C. bornhalmi (from loc. 6) and in C. biguttulus eximius (from loc. 34) fall into the range of values in C. maritimus from several localities (Table 3 , Fig. 5C, D ). The syllable structure is also quite similar in C. bornhalmi (Fig. 6E ) and C. biguttulus eximius (Fig. 6F ).

Courtship song.

The courtship song of C. maritimus is similar to the calling song.

Rivalry song

(Fig. 6G, H ). The rivalry song of C. maritimus contains echemes of a shorter duration than the calling song. In some males the first syllable of the rivalry echeme lasts 1.5-2 times as long as the subsequent syllables, which results from the prolonged first downstroke (Fig. 6H ). The pulses produced during the first downstroke are repeated twice as slowly as the pulses of the subsequent syllables. The subsequent 2-8 syllables are of the same structure as the syllables in the calling song.

Figures

Figure 1. Map of localities where the specimens of Chorthippus brunneus (green triangles), C. maritimus (red squares) and C. miramae (blue circles) were collected. The localities with song recordings are numbered and marked by filled icons.

Figure 3. Morphological differences between Chorthippus brunneus (green dots), C. maritimus (red dots), and C. miramae (blue dots). A, B length of stridulatory file vs. distance from the last stridulatory peg to the tip of knee in males (A) and females (B) C, D results of Principal Component Analysis based on 6 characters are shown for PC 1 and PC 2 in males (C) and females (D) E loadings of different characters to PC 1 and PC 2.

Figure 5. Differences in calling songs between Chorthippus brunneus, C. maritimus, and C. miramae A-D boxplots for the Chorthippus brunneus - like echeme duration (A) for the Chorthippus brunneus - like pulse rate (B) for the Chorthippus maritimus - like echeme duration (C) and the Chorthippus maritimus - like syllable duration (D) medians (dots), first and third quartiles (boxes), the 10 th and 90 th percentiles (whiskers), and outliers (dots beyond whiskers) are shown E results of Principal Component Analysis based on 5 song characters are shown for PC 1 and PC 2 in C. brunneus (green dots), C. maritimus (red dots), and C. miramae (blue dots) F loadings of different characters to PC 1 and PC 2.

Figure 6. Oscillograms of calling songs A-F and rivalry songs G, H in Chorthippus maritimus from Primorskiy kray (A) Macedonia (B) Sukhumi region (C) and Saratov region (G). Song recordings are presented at three different speeds (faster oscillograms of the indicated parts of the songs shown in D, E, F, H). In all oscillograms the two upper lines are recordings of hind leg movements and the lower line is the sound recording. The ambient temperature near a singing male was 33 - 34 ° C in (A) and 29 - 30 ° C in other cases.