Bembecia (s. str.) pallasi, Gorbunov, 2020

Gorbunov, Oleg G., 2020, A new and poorly known clearwing moth of the genus Bembecia Hübner, 1819 [“ 1816 ”] from the European part of Russia and northwestern Kazakhstan (Lepidoptera, Sesiidae), Zootaxa 4729 (4), pp. 551-565 : 556-564

Bembecia (s. str.) pallasi sp. nov.

( Figs 17–31 , 33 , 37–39 )

Holotype ♂ ( Figs 17–18 ), “ Kazakhstan, Atyrau Reg., / 60 km NE Kulsary, Imankara , / 47° 25’ N, 54° 30’ E, / 08–10.V.1997, ex l., / O. Gorbunov leg.; “Host plant: / Astragalus longipetalus / ( Fabaceae ) / Moth emerged 2.VI.1997 ”; “ Sesiidae / Pictures №№ / 0211-0212–2015 / Photo by O. Gorbunov ”; “HOLOTYPUS ♂ / Bembecia pallasi / O. Gorbunov, 2019 / O. Gorbunov des., 2015” ( COGM).

Paratypes (18 ♂♂, 2 ♀♀), 1 ♂, 2 ♀♀, same locality and date as holotype, ex larvae from roots of Astragalus longipetalus , moths emerged 24.V. and 01.VI.1997, O. Gorbunov leg. (1 ♀ with Sesiidae pictures №№ 0213-0214– 2015, male with genitalia preparation № OG–027-1997, 1 ♀ with genitalia preparation № OG–051–1997) ( COGM); 2 ♂♂, Russia, Orenburg Region, 10 km W of Podgornoye, 51° 12’ N, 057° 30’ E, 25.V.1998, O. Gorbunov leg. (1 ♂ with Sesiidae pictures №№ 0215-0216–2015) ( COGM); 7 ♂♂, same locality, 26.V.1998, O. Gorbunov leg. (6 ♂♂ with Sesiidae pictures №№ 0183-0194–2014) ( COGM); 3 ♂♂, Kazakhstan, Aktyubinsk Region, 5 km NW of Uil, 49° 05’ N, 054° 35’ E, 100 m, 29.V.1998, O. Gorbunov leg. (1 ♂ with Sesiidae pictures №№ 0195-0196–2014) ( COGM); 2 ♂♂, Kazakhstan, Aktyubinsk Region, 50 km SSE of Sagiz, Aktolagai , 47° 47’ N, 055° 08’ E, 200 m, 31.V.1998, O. Gorbunov leg. (2 ♂♂ with Sesiidae pictures №№ 0197-0200–2014) ( COGM); 3 ♂♂, Kazakhstan, Aktyubinsk Region, 26 km, W of Novoalekseevka, 50° 10’ N, 055° 18’ E, 06.VI.1998, O. Gorbunov leg. (2 ♂♂ with Sesiidae pictures №№ 0201-0204–2014) ( COGM) .

Description. Male (holotype) ( Figs 11–12 ). Alar expanse 20.5 mm; body length 12.6 mm; forewing 9.0 mm; antenna 6.2 mm.

Head with antenna entirely dark brown to black with dark greenish sheen; frons dark brown to black with blueviolet sheen; vertex black with dark greenish sheen and a few white hair-like scales; labial palpus entirely dark brown to black with dark greenish sheen; pericephalic hairs dark brown to black.

Thorax with patagia entirely dark brown to black with bright green-bronze sheen; tegula and mesothorax dark brown to black with greenish-blue sheen, sparsely covered with white hair-like scales; metathorax dark brown to black with greenish-blue sheen and a tuft of white hairs laterally; thorax laterally dark brown to black with greenish-blue sheen; posteriorly both metepimeron and metameron black with dark blue-violet sheen, densely covered with long black hairs. Legs with neck plate dark brown to black with greenish-blue sheen; fore coxa dark brown to black with greenish sheen; fore femur dark brown to black with greenish-violet sheen; fore tibia dark brown to black with greenish sheen dorsally and pale yellow ventrally; fore tarsus entirely dark brown to black with greenish sheen; mid coxa and mid femur dark brown to black with bright greenish sheen and white hairs on posterior margin of femur; mid tibia dark brown to black with bright greenish-violet sheen and a broad orange ring medially; spurs dark brown to black with violet sheen; mid tarsus entirely dark brown to black with greenish sheen; hind coxa and hind femur dark brown to black with bright greenish sheen and white hairs on posterior margin of femur; hind tibia orange with a narrow dark brown to black ring with bright greenish sheen basally; spurs dark brown to black with violet sheen; hind tarsus entirely dark brown to black with greenish sheen. Forewing dorsally with basal part black with greenish-blue sheen; costal margin up to tip of vein R 3 and discal spot dark brown to black with bright green sheen; CuA-stem, anal margin, narrow distal spot, veins R 5 –CuA 2 and apical area orange; ventrally costal margin up to tip of vein R 2 pale yellow; proximal 2/3 of discal spot and surface between veins R 2 –R 3 dark brown to black with greenish-violet sheen; other coloured scales pale orange; transparent areas well-developed, but densely covered with translucent scales with light golden-greenish hue; posterior transparent area not reaching discal spot; external transparent area large, divided into six cells between veins R 3 and CuA 1, level to vein M 2 about 2.7 times as broad as discal spot and apical area; cilia brown with bronze sheen. Hindwing transparent; dorsally veins dark brown with greenish sheen and a few orange scales; discal spot narrow, triangular, reaching the base of vein M 2, dark brown with greenish sheen; outer margin narrow, about 0.4 times as broad as cilia, dark brown to black with bronze-violet sheen, anally orange; ventrally veins pale yellow with an admixture of dark brown scales; discal spot dark brown with greenish sheen; outer margin dark brown to black with bronze sheen; cilia brown to dark brown with bronze sheen.

Abdomen dorsally dark brown to black with bright greenish-violet sheen; tergite 4 with a row of white scales distally, tergite 6 with a few white scales distally; ventrally entirely dark brown to black with bright greenish sheen; anal tuft dorsally dark brown to black with greenish sheen medially and orange laterally; ventrally dark brown to black with violet sheen.

Male genitalia (Genital preparation № OG–027-1997) ( Figs 27–30 ). Tegumen-uncus complex relatively broad; scopula androconialis short, about 0.4 times as long as tegumen-uncus complex ( Fig. 27 ); crista gnathi medialis long and broad; crista gnati lateralis semi-oval, about 0.8 times as long as and about 0.5 times as broad as crista gnathi medialis ( Fig. 27 ); valva ( Fig. 28 ) trapeziform-ovoid, crista sacculi oblique, covered with apically pointed setae anteriorly and flat-topped ones posteriorly; caudal part of setae bent towards ventral margin and slightly anteriorly; saccus ( Fig. 29 ) narrow, somewhat broadened subbasally, long, about twice as long as vinculum; aedeagus ( Fig. 30 ) thin, slightly sinuate and about as long as valva; vesica with numerous small cornuti.

Female (paratype) ( Figs 19–20 ). Alar expanse 21.3 mm; body length 12.6 mm; forewing 10.0 mm; antenna 5.6 mm.

Head with antenna entirely dark brown to black with dark greenish sheen; frons dark brown to black with blueviolet sheen; vertex black with dark greenish sheen; labial palpus entirely dark brown to black with dark greenish sheen; occipital dark brown to black.

Thorax with patagia entirely dark brown to black with bright green-bronze sheen; tegula and mesothorax dark brown to black with greenish-blue sheen, sparsely covered with white hair-like scales; metathorax dark brown to black with greenish-blue sheen and a tuft of orange hairs laterally; thorax laterally dark brown to black with greenish-blue sheen; posteriorly both metepimeron and metameron black with dark blue-violet sheen, densely covered with long black hairs. Legs with neck plate dark brown to black with greenish-blue sheen; fore coxa dark brown to black with greenish sheen; fore femur dark brown to black with greenish-violet sheen; fore tibia dark brown to black with greenish sheen dorsally and pale yellow ventrally; fore tarsus entirely dark brown to black with greenish sheen; mid coxa and mid femur dark brown to black with bright greenish sheen and white hairs on posterior margin of femur; mid tibia dark brown to black with bright greenish-violet sheen and a broad orange ring medially; spurs dark brown to black with violet sheen; mid tarsus entirely dark brown to black with greenish sheen; hind coxa and hind femur dark brown to black with bright greenish sheen and white hairs on posterior margin of femur; hind tibia orange with a narrow dark brown to black ring with bright greenish sheen basally; spurs dark brown to black with violet sheen; hind tarsus entirely dark brown to black with greenish sheen. Forewing dorsally with basal part black with greenish-blue sheen; costal margin up to tip of vein R 4 dark brown to black with bright green sheen; proximal 2/3 of discal spot dark brown to black with bright blue-violet sheen; CuA-stem, anal margin, distal 1/3 of distal spot, veins R 5 –CuA 2 and apical area orange; ventrally costal margin up to tip of vein R 2 pale yellow; proximal 2/3 of discal spot and surface between veins R 2 –R 4 dark brown to black with greenish-violet sheen; other coloured scales orange; transparent areas less developed (posterior transparent area nearly undeveloped) and densely covered with translucent scales with light golden-greenish hue; external transparent area rather large, divided into five cells between veins R 3 and CuA 1, level to vein M 2 about 1.75 times as broad as discal spot and apical area; cilia brown with bronze sheen. Hindwing transparent, but densely covered with orange scales anally; dorsally veins dark brown with greenish sheen and an admixture of orange scales on common CuA-stem and veins 1A and 2A; discal spot narrow, cuneiform, reaching the base of common stem CuA 1 –M 3, dark brown with greenish sheen and a few orange scales; outer margin narrow, about 0.5 times as broad as cilia, dark brown to black with bronze sheen, anally orange; ventrally common stem CuA pale yellow, veins 1A and 2A orange, other veins dark brown with a few orange scales; discal spot dark brown with greenish-blue sheen and a few orange scales; outer margin dark brown to black with bronze sheen; cilia brown to dark brown with bronze sheen.

Abdomen dorsally dark brown to black with bright greenish sheen; tergites 2 and 4 each with a narrow pale yellow stripe distally; dark brown to black with bright greenish sheen ventrally; sternite 4 with a small yellow-orange spot lateral-distally; anal tuft dark brown to black with greenish sheen medially and orange laterally.

Female genitalia (Genital preparation № OG–051-1997) ( Fig. 31 ). Papillae anales relatively broad, covered with short and long setae; tergite 8 broad with short and long setae ventrally and distally, triangular, with ventral margin folded inside; posterior apophysis about 1.5 times as long as anterior apophysis; both lamellae antevaginalis and postvaginalis undeveloped; ostium bursae slightly funnel-shaped, situated medio-ventral to tergite 8; antrum relatively narrow, long, about 0.7 time longer than anterior apophysis, well-sclerotized; ductus bursae membranous, about as broad as antrum; corpus bursae ovoid, without signum.

Individual variability. Males ( Figs 11–18 ) vary in the number of white scales on the abdomen dorsally. So there is a male form ( Fig. 15 ) with no white scales on the abdomen. On the other hand, there is a male form ( Fig. 13 ) with a few white scales on the distal margin of the second tergite. Females are practically invariable. Besides this, the transparent areas of the forewing are slightly variable as well. Individual sizes range as follows. Males: alar expanse 18.0– 20.5 mm; body length 11.5–12.6 mm; forewing 8.0–9.0 mm; antenna 5.1–6.2 mm. Females: alar expanse 18.2–21.3 mm; body length 9.8–12.6 mm; forewing 9.0–10.0 mm; antenna 4.9–5.6 mm.

Differential diagnosis. By the shape of the crista sacculi of the male genitalia, this new species seems to be close to the central Asian B. turanica ( Erschoff, 1874) , B. viguraea ( Püngeler, 1912) and B. alaica ( Püngeler, 1912) . Superficially, B. pallasi sp. nov. can be distinguished from B. turanica by the colouration of the frons (entirely dark brown to black with blue-violet sheen in B. pallasi sp. nov., vs. dark grey-brown with a narrow snow-white stripe laterally in B. turanica ), tegula (entirely dark brown to black with greenish-blue sheen in B. pallasi sp. nov., vs. with a narrow yellowish in male and orange-red in female inner margin in B. turanica ), abdomen dorsally (dark brown to black with bright greenish-violet sheen, tergite 4 with a row of white scales distally, tergite 6 with a few white scales distally in male and dark brown to black with bright greenish sheen, tergites 2 and 4 each with a narrow pale yellow stripe distally in female of B. pallasi sp. nov., instead dark brown to black with greenish sheen, tergites 2, 4, 6 and 7 each in male and tergites 4 and 6 each in female with pale yellow stripe distally in B. turanica ) and by the conformation of the external transparent area of the forewing (external transparent area large, divided into six cells between veins R 3 and CuA 1, level to vein M 2 about 2.7 times as broad as discal spot and apical area in male and divided into five cells between veins R 3 and CuA 1, level to vein M 2 about 1.75 times as broad as discal spot and apical area in female of B. pallasi sp. nov., vs. external transparent area noticeably less, divided into four cells between veins R 4+5 and CuA 1 in male and between veins R 4+5 and M 3 in female of B. turanica ), as well as by the shape of the crista gnathi and crista sacculi in the male genitalia (compare Figs 27 and 28 and text-fig. 136 in Špatenka et al. 1999: 491).

B. pallasi sp. nov. is clearly separable from B. viguraea by the colouration of the abdomen dorsally (tergite 4 with a row of white scales distally, tergite 6 with a few white scales distally in male and tergites 2 and 4 each with a narrow pale yellow stripe distally in female of B. pallasi sp. nov., instead tergite 4 with a broad pale yellow to white stripe distally in male and tergites 2, 4 and 6 each with a broad pale yellow to yellow stripe distally in female of B. viguraea ), by the structure of the external transparent area of the forewing (external transparent area large, divided into six cells between veins R 3 and CuA 1, level to vein M 2 about 2.7 times as broad as discal spot in male and divided into five cells between veins R 3 and CuA 1, level to vein M 2 about 1.75 times as broad as discal spot in female of B. pallasi sp. nov., vs. external transparent area noticeably less, divided into four cells between veins R 4+5 and CuA 1, level to vein M 2 about twice as broad as discal spot in B. viguraea ), as well as by the shape of the crista gnathi and crista sacculi in the male genitalia (compare Figs 27 and 28 and text-fig. 137 in Špatenka et al. 1999: 491).

The new species differs from B. alaica by the colouration of the abdomen dorsally (tergite 4 with a row of white scales distally, tergite 6 with a few white scales distally in male and tergites 2 and 4 each with a narrow pale yellow stripe distally in female of B. pallasi sp. nov., vs. tergites 2 and 4 each with a very narrow white stripe distally in both male and female of B. alaica ), by the conformation of the transparent areas of the forewing (well-developed; posterior transparent area short, but present; external transparent area large, divided into six cells between veins R 3 and CuA 1 in male and divided into five cells between veins R 3 and CuA 1 in female of B. pallasi sp. nov., instead posterior transparent area undeveloped; external transparent area small, divided into three cells between veins R 4+5 and M 3 in male and completely undeveloped in female of B. alaica ). Beside this, these two species differ in the structure of the genitalia of both male and female (compare Figs 27 and 28 and text-figs 133 and 384 in Špatenka et al. 1999: 491, 531).

From all other congeners B. pallasi sp. nov. is separable by the colouration of various parts of the body, wings and by the structure of the genitalia of both male and female.

Bionomics. The larval host is Astragalus longipetalus Chater (Fabaceae) ( Fig. 37 ). However, in the Orenburg Region, males of the type series were collected in a biotope where this species of astragals was absent, but A. wolgensis Bunge was present ( Fig. 38 ). With a high degree of probability, this astragalus is also a host plant of this new species. The larva lives in the root where it bores a tunnel about 7–9 cm long. Its life cycle is annual. Before pupation, the larva makes an exit tube to the surface of the ground. Pupation occurs in the upper part of the exit tube without the construction of a cocoon. This is the first example of the pupation of a species of the genus Bembecia without a cocoon. The result of this anomaly was that several pupae, being in the upper part of the exit tube, were crushed during excavation of the roots of the host plants. Adults are on the wing from the end of May to the beginning of June ( Fig. 33 ). Males are attracted to artificial pheromones slightly before noon.

Habitat. This species inhabits different types of herbaceous steppes and wormwood-herbaceous semi-deserts ( Fig. 39 ) with the obligatory presence of the host plants, Astragalus spp.

Distribution. The new species is known from a few localities in the southeastern European part of Russia (Orenburg Region) and northwestern part of Kazakhstan (Aktyubinsk Region).

Etymology. This new species is named in honour of Peter Simon Pallas (1741–1811), a Prussian natural philosopher, an academician of Saint Petersburg Academy of Sciences, who led en expedition (1769–1770) to the southern provinces of the Russian Empire, where this new species occurs.

Figures

FIGURES 17–26. Variability of Bembecia pallasi sp. nov. 17) ♂ holotype, upside. Sesiidae picture № 0211–2015.Alar expanse 20.5 mm; 18) ditto underside. Sesiidae picture № 0212–2015; 19) ♂ paratype, upside. Sesiidae picture № 0183–2014. Alar expanse 20.0 mm; 20) ditto underside. Sesiidae picture № 0184–2014; 21) ♂ paratype, upside. Sesiidae picture № 0189–2014. Alar expanse 18.0 mm; 22) ditto underside. Sesiidae picture № 0190–2014; 23) ♂ paratype, upside. Sesiidae picture № 0197– 2014. Alar expanse 20.5 mm; 24) ditto underside. Sesiidae picture № 0198–2014; 25) ♀ paratype, upside. Sesiidae picture № 0213–2015. Alar expanse 21.3 mm; 26) ditto underside. Sesiidae picture № 0214–2015.

FIGURES 27–31. Genitalia of Bembecia pallasi sp. nov. 27–30. ♂ genitalia, paratype. Genital preparation № OG–027-1997. 27) tegumen-uncus complex; 28) valva; 29) saccus; 30) aedeagus. 31) ♀ genitalia, paratype. Genitalia preparation № OG–051- 1997. Scale bar: 0.5 mm.

FIGURES 32–33. Freshly emerged males of Bembecia spp. 32) B. sareptana (Bartel, 1912). Russia, Orenburg Region, 5 km NW of Olkhovka, 26.V.1998, ex pupae from a root of Oxytropis floribunda (Pall.) DC (Fabaceae), moths emerged 29.V.1998; 33) B. pallasi sp. nov. holotype. Kazakhstan, Atyrau Reg., 60 km NE Kulsary, Imankara, 08–10.V.1997, ex larva from a root of Astragalus longipetalus Chater (Fabaceae), moth emerged 2.VI.1997.

FIGURES 37–39. Life history of Bembecia pallasi sp. nov. 37) Astragalus longipetalus Chater (Fabaceae), the host plant. Kazakhstan, Atyrau Reg., 60 km NE Kulsary, Imankara, 10.V.1997; 38) A. wolgensis Bunge, a probable host plant. Russia, Orenburg Region, 10 km W of Podgornoye, 25.V.1998; 39) habitat (type locality), Kazakhstan, Atyrau Reg., 60 km NE Kulsary, Imankara, 10.V.1997.

FIGURES 11–16. Genitalia of Bembecia sareptana (Bartel, 1912). 11–15. ♂ genitalia. Genital preparation № OG–006-1998. 11) tegumen-uncus complex; 12) valva; 13) saccus; 14) aedeagus; 15) vesica. 16) ♀ genitalia. Genitalia preparation № OG–007- 1998. Scale bar: 0.5 mm for 11–14 and 16, 0.2 mm for 15.