Chorthippus brunneus (Thunberg)

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 brunneus (Thunberg)

Gryllus brunneus Thunberg, 1815: 256.

Material examined.

Bulgaria: 4 Sofia region, lake Iskyr , 29.VI.2002, 1 ♂ 5 ♀, leg. V. Vedenina, song recordings in 1 ♂ (CV) ; Moldova: 10 Vinnitza region, Volchinetz , ab. 5 km W Mogilev-Podol’sky, 17.VII.1997, 1 ♂, leg. V. Vedenina (CV) ; Romania: 11 Dobrudzha region, 14 km S Constantza, Ephoria-Nord , 09.IX.1997, 2 ♂ 3 ♀, leg. A. Loginov (ZMMU) ; Ukraine: 8 Ivano-Frankovsk region, environs of Mikulichin, 09-14.VIII.1996, 6 ♂ 1 ♀, leg. V. Vedenina (CV); 9 Khmelnitsky region, 28 km NNW of Kamenetz-Podolsky, near Beloe , 25.VI.2010, 1 ♂ 1 ♀, leg. V. Vedenina, song recordings in 1 ♂ (CV); 12 Odessa region, Kiliya district, environs of Vilkovo , 30.VI.1997, 2 ♂, leg. V. Vedenina (CV); 13 Odessa region, ab. 30 km NW of Belgorod-Dnestrovsky, near Krasnaya Kosa village, 29.VI.1997, 1 ♂, leg. V. Vedenina (CV); 16 Nikolaev region, Pervomaisk district , surr. of Kuripchino village , 27.06.1997, 1♂, leg. V. Vedenina (CV); 18 Cherkassy region , Kanev district , Kanev reserve , 12-18.VI.1996, 12 ♂ 5 ♀, leg. V. Vedenina (ZMMU); 19 Kirovograd region, environs of Aleksandriya, 04.VII.1997, 2 ♂ 2 ♀, leg. V. Vedenina (CV); 20 Nikolaev region, Pervomaisk district , environs of Kuripchino village , beach of Yuzhny Bug river , 27.VI.1997, 1 ♂ 1 ♀, leg. V. Vedenina, song recordings in 2 ♂ (CV); 22 Poltava region, Mirgorod district., V. Sorochintzy, 27-28.VI.1985, 4 ♂ 5 ♀, 25-28.VII.1993, 3 ♂ 5 ♀, 24.VII-26.VIII.1994, 5 ♂, leg. V. Vedenina, song recordings in 6 ♂ (ZMMU, CV); 25 Dnipro region , Pavlograd district , Samara reserve , 12-15.VII.1996, 4 ♂ 4 ♀, leg. V. Vedenina (CV) ; Russia: 1 Kaliningrad region, environs of Svetlogorsk , forest road, 16.VIII.2005, 3 ♂ 1 ♀, leg. N. Kulygina , song recordings in 1 ♂ (CV); 14 St-Peterburg, 27.08.1997, 1 ♂, leg. V. Vedenina (CV); 32 Voronezh region, Novaja Usman’ district, near Maklok village , 29.VI.2006, 3 ♂, leg. N. Kulygina (CV); 35 Kostroma region, Manturovo district, environs of. Anosovo , 07-08.VIII.2009, 2 ♂ 1 ♀, leg. V. Vedenina, song recordings in 2 ♂ (CV); 40 Saratov region, Krasny Kut district , near D‘yakovka, 17.VII.2004, 3 ♂, leg. D. Tishechkin, song recordings in 2 ♂ (ZMMU) .

Distribution.

(Fig. 1 ). The range of this species extends from Europe to the south-western part of European Russia. In Europe this species occurs over a wide range, excluding the central and southern part of the Iberian Peninsula and Greece ( Ragge and Reynolds 1988, Sirin et al. 2010). Further to the east, it occurs in the Baltic republics, Belarus, Moldova, and Ukraine. The eastern border of the range lies on the longitude of the Saratov and Kostroma regions of Russia. The species tends to be mesophilic. The range of C. brunneus overlaps with that of C. maritimus in south-eastern Europe, Moldova, Ukraine, and the south-eastern part of European Russia.

Recognition.

(Table 1 , Fig. 3 ). The males of C. brunneus can be distinguished from the males of C. miramae and C. maritimus by a short stridulatory file (Fig. 3A ). This, however, is not applicable to the females (Fig. 3B ). Both sexes of C. brunneus are characterized by the lowest number of stridulatory pegs (58-93 in ♂, 51-95 in ♀.). In comparison with C. miramae and C. maritimus , both sexes of C. brunneus tend to have the shortest pronotum, the narrowest C & Sc areas of fore wing, and the stigma closest to the wing tip (Table 1 ). The PCA applied to 6 characters shows a substantial overlap between C. brunneus and C. maritimus (Fig. 3C, D ). In PCA, however, we do not use the number of stridulatory pegs, since this value was measured for a small number of males. Meanwhile, it was previously shown that C. brunneus can be easily distinguished from all other species of the C. biguttulus group by the lowest number of stridulatory pegs, especially in nominate subspecies ( Oliger 1974; Ragge and Reynolds 1988; Bukhvalova 1993; Willemse et al. 2009).

Calling song

(Table 2 , Figs 4 , 5 ). The calling song of C. brunneus consists of several short echemes repeated at the rate of about 0.3-2.1 /s. Each echeme lasts on average 0.1-0.4 s and has a relatively stable temporal structure. It consists of short pulses, which are grouped into 4-7 syllables (Fig. 4C ). The gaps between the subsequent syllables can’t be traced by the sound analysis, but they can be distinguished by the analysis of the leg movements. The two legs are moved with a large phase shift, and sometimes almost alternately (Fig. 4E ). Each leg generates one short pulse during a straight upstroke, whereas two short pulses are produced during a two-step downstroke. The pulse duration and the pulse rate vary in the ranges of 7-8 ms and 91-111/s, respectively (at the temperature 29-30°C). The population from loc. 40, shows an extremely long echeme duration and low echeme and pulse rate (Table 2 ). Notably, the values are relatively stable within the same population.

Courtship and rivalry songs.

The courtship and rivalry (Fig. 4F, G ) songs of C. brunneus are similar to 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 4. Oscillograms of calling songs A-E and rivalry songs F, G in Chorthippus brunneus from Kostroma region (A) Poltava region (B) and Saratov region (F). Song recordings are presented at four different speeds (faster oscillograms of the indicated parts of the songs shown in C, D, E, G). In all oscillograms the two upper lines are recordings of hind leg movements and the lower line is the sound recording. Different song parameters are indicated by brackets and arrows. The ambient temperature near a singing male was 29 - 32 ° C.

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.