Bembecia strandi (W. Kozhantschikov, 1936 )

Gorbunov, O. G., 2025, A redescription of Bembecia strandi (Lepidoptera: Sesiidae), Zoosystematica Rossica (China) 34 (1), pp. 138-148 : 139-146

Bembecia strandi (W. Kozhantschikov, 1936)

( Figs 1–20)

Dipsosphecia strandi Kozhantschikov, 1936: 26 [“ Dipsosphecia Strandi spec. nov. ”]. Type locality: “okr. Minusinska …” [= Russia: Krasnoyarsk Terr., Minusinsk Distr., Tagarskiy Island], by lectotype (male), designated by Gorbunov (1992).

Literature. Heppner & Duckworth, 1981: 40 ( Bembecia ); Gorbunov, 1992: 70 ( Bembecia ); Špatenka et al., 1993: 100 ( Bembecia ); Špatenka et al., 1996: 9 ( Bembecia ); Špatenka et al., 1999: 177 (key), 202, pl. 26, figs 207, 208 ( Bembecia ); Pühringer & Kallies, 2004: 36 ( Bembecia ); Gorbunov, 2008: 111 ( Bembecia ); Gorbunov, 2018a: 273 ( Bembecia ); Gorbunov, 2019a: 160 ( Bembecia ); Gorbunov, 2020a: 554 ( Bembecia ).

Type material examined. Lectotype. Male with following labels ( Fig. 3): Okr. Minusinska / 19. VI. / 1933 Kozhantschikov [in Russian ]; golden circle; SESIIDAE / Pictures №№ / 0155-0156–2018 / Photo by O. Gorbunov; Genitalia examined / by O.G. Gorbunov / Preparation № / OG–029-2024; Bembecia ♂ / strandi (Kozh.) ; LECTOTYPUS ♂ / Bembecia strandi / W. Kozhantschikov, / 1936 / O.G. Gorbunov des., 1992 ( ZISP).

Paralectotype. Female with following labels ( Fig. 6): Okr. Minusinska / 8.VII. / 1930 Kozhantschikov [in Russian ]; golden circle; SESIIDAE / Pictures №№ / 0157-0158–2018 / Photo by O. Gorbunov; Genitalia examined / by O.G. Gorbunov / Preparation № / OG– 030-2024; Bembecia ♀ / strandi (Kozh.) ; PARALEC- TOTYPUS ♀ / Bembecia strandi / W. Kozhantschikov, / 1936 / O.G. Gorbunov des., 1992 ( ZISP).

Other material examined. Russia, Krasnoyarsk Terr., Minusinsk Distr. , Tagarskiy I .: 53°38′44.8″N, 91°35′32.6″E, 316 m, 13.VII.2023, O.G. Gorbunov leg., 1 male ( Sesiidae pictures Nos 0141-0142–2023; Figs 7, 8; COGM) ; 53°38′27.1″N, 91°35′7.1″E, 289 m, 13.VII.2023, O.G. Gorbunov leg., 1 male ( Sesiidae pictures Nos 0139-0140–2023; Figs 9, 10; COGM) ; 53°38′53.3″N, 91°35′47.6″E, 313 m, 13.VII.2023, O.G. Gorbunov leg., 1 male ( Sesiidae pictures Nos 0143-0144–2023; COGM) ; 53°38′43.7″N, 91°35′10.6″E, 331 m, 14.VII.2023, O.G. Gorbunov leg., 4 males (1 male with Sesiidae pictures Nos 0145-0146–2023; COGM) ; 53°38′27.6″N, 91°35′07.8″E, 291 m, 14.VII.2023, O.G. Gorbunov leg., 1 male ( Sesiidae pictures Nos 0147-0148–2023; Figs 11, 12; COGM) ; 53°39′41.0″N, 91°37′25.9″E, 261 m, 15.VII.2023, O.G. Gorbunov leg., 2 males ( Sesiidae pictures Nos 0149-0152–2023; Figs 13, 14; COGM) .

Redescription. Male (non type-specimen: Figs 7, 8). Wing span 22.2 mm; body length 13.1 mm; forewing length 10.0 mm; length of antenna 7.0 mm.

Head. Antenna and scapus black with dark blue greenish sheen. Frons white to pale yellow with golden tint and admixture of several black scales medially. Vertex black with dark greenish violet sheen and few pale yellow to white, long, hair-like scales. Labial palpus pale yellow to yellow with narrow black stripe ventroexternally. Occipital fringe yellowish with short yellow part at upper corner of eye. Neck plate black with bright greenish blue sheen.

Thorax. Patagium black with bright bronze violet sheen and small yellow spot laterally. Tegula black with greenish blue sheen, pale yellow spot with golden tint at base of forewing and dark yellow scales distally. Meso- and metathorax completely black with dark greenish violet sheen. In addition, tegula, meso- and metathorax densely covered with pale yellow to white, long, hair-like scales masking background coloration. Thorax laterally black with bright greenish violet sheen and several yellow scales. Posteriorly, both metepimeron and metameron black, densely covered with white, long, hair-like scales.

Legs. Fore coxa pale yellow with golden tint and several black scales medially. Fore femur externally dark yellow, internally black with white, long, hair-like scales at posterior margin. Fore tibia ventrally yellow with golden tint, dorsally yellow-orange with admixture of black scales basally. Fore tarsus pale yellow with golden tint ventrally and yellow dorsally. Mid coxa black with bright greenish violet sheen. Mid femur black with bright greenish blue sheen and with white, long, hair-like scales at posterior margin. Mid tibia ventrointernally black with bright violet sheen, dorsoexternally black with bright blue sheen, large orange spot medially and few orange scales distally; spurs pale yellow with golden tint. Mid tarsus internally pale yellow with golden tint, externally yellow with golden tint. Hind coxa black with bright greenish violet sheen. Hind femur black with bright greenish blue sheen and with white, long, hair-like scales at posterior margin. Hind tibia orange with black spots with bright violet sheen basally and interiorly subdistally; spurs pale yellow with golden tint. Hind tarsus internally pale yellow with golden tint, externally yellow with golden tint.

Forewing dorsally with basal part black with dark greenish sheen; costal margin up to tip of vein R 1 black with dark violet sheen and admixture of individual orange scales; CuA –stem orange; anal margin orange with few black scales distally; discal spot black with dark violet sheen in basal half and orange in distal half; veins within external transparent area orange; apical area orange with black scales on vein R 4; outer margin extremely narrow, black with dark violet sheen; cilia grey-brown with bronze sheen. Forewing ventrally with costal margin up to tip of vein R 1 pale yellow to yellow; CuA –stem and anal margin yellow-orange with golden tint; discal spot black with dark violet sheen in basal half and orange in distal half; surface between veins R

1

and R

3

black with dark violet sheen and few orange scales; surface between veins CuA 1 and CuA 2 with mixed yellow-orange and black scales; veins R

4

and R

5

black with several yellow-orange scales; apical area yellow-orange with few black scales on veins M 1 –M 3; cilia grey-brown with bronze sheen; transparent areas rather well-developed, but densely covered with translucent scales with light greenish golden tint; anterior transparent area divided into two parts by extremely narrow scaled line; posterior transparent area short, only slightly extending distad to level of discal spot of hind wing; external transparent area rather small, rounded distally, divided into five cells between veins R 3 and CuA 1, level to vein M 2 about 1.25 times as broad as discal spot and about 1.7 times as broad as apical area. Cilia brown with bronze sheen.

Hind wing transparent; dorsally vein M 2 dark brown with bronze sheen, vein CuP mixed with orange and black scales, remaining veins black with dark violet sheen; discal spot cuneiform, reaching base of common stem of veins M 3 – CuA 1, black with dark violet sheen and several orange scales; outer margin dark brown with bronze-violet sheen, slightly narrower than cilia; ventrally veins M 2 and CuP yellow-orange, remaining veins dark brown with bronze sheen and admixture of yellow-orange scales; discal spot yellow-orange with several dark brown scales; outer margin yellow-orange with admixture of dark brown scales with bronze sheen; cilia brown with bronze sheen, white anally.

Abdomen black with greenish bronze sheen. Tergites 2, 4, 6, and 7 each with rather broad yellow stripe with golden tint distally; tergites 3 and 5 each with admixture of yellow scales with golden tint in distal half. Sternite 4 with broad yellow stripe with golden tint distally; basal sternite and sternites 5–7 each with admixture of yellow scales with golden tint distally; sternite 3 with several thin yellow-orange scales medially. Anal tuft dorsally black with greenish blue sheen and with several yellow-orange scales medially; anal tuft ventrally black with greenish violet sheen, medially yellow-orange.

Male genitalia (lectotype; genital preparation No. OG–029-2024; Figs 15–19). Tegumen– uncus complex relatively broad; scopula androconialis well-developed, about 0.5 times as long as tegumen–uncus complex ( Fig. 15); crista gnathi medialis broad, semi-rhombic; crista gnathi lateralis narrow and short ( Fig. 15); valva ( Fig. 16) trapezoid; crista sacculi complex with two distinct parallel ridges: ventral ridge short, but dorsal one long, densely covered with strong, pointed setae, which becoming flat-topped at distal end; these flat-topped setae forming one group joining with similar flat-topped setae at distal end of ventral ridge; saccus ( Fig. 17) relatively narrow, with rounded base, long, about 1.5 times as long as vinculum; aedeagus ( Fig. 18) rather narrow, straight, about as long as length of valva; vesica with numerous strong cornuti ( Fig. 19).

Female (paralectotype: Figs 4, 5). Somewhat more robust than male; wing span 26.0 mm; body length 13.5 mm; forewing 11.8 mm; antenna broken off.

Head with frons yellow-orange with golden tint and narrow black stripe with bright violet sheen laterally; vertex orange; labial palpus yellow-orange; occipital fringe yellow-orange with several black scales; neck plate black with bright blue violet sheen and several yellow-orange scales. Thorax with tegula with narrow yellow-orange inner margin. Legs with fore coxa dark brown to black with blue-violet sheen; mid and hind tibial spurs yellow-orange. Forewing with narrow short posterior transparent area, not reaching level of discal spot of hind wing; external transparent area divided into four cells between veins R 5 and CuA 1, level to vein M 2 about 1.7 times as broad as discal spot and about 3.3 times as broad as apical area. Hind wing with veins M 2, CuP and anal veins yellow-orange. Abdomen dorsally with tergites 2, 4 and 6 each with rather broad yellow stripe distally; ventrally sternite 4 with broad yellow stripe distally, sternite 6 with few yellow scales at distal margin; anal tuft small, yellow-orange medially and dark brown to black with violet sheen laterally.

Otherwise, coloration and morphological details same as those of male.

Female genitalia (paralectotype; genital preparation No. OG–030-2024; Fig. 20). 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 slightly longer than anterior apophysis; both lamellae antevaginalis and postvaginalis undeveloped; ostium bursae slightly fungoid, situated medioventrally to tergite 8; antrum relatively narrow, long, slightly shorter than anterior apophysis, well-sclerotised; ductus bursae membranous, slightly broader than antrum, with numerous wrinkles medially, long, about 0.8 times length of antrum; corpus bursae ovoid, without signum.

Individual variability. Unknown for females. Males somewhat vary in the number of yellow-orange and orange scales on abdomen and hindwing. Besides this, transparent areas of the forewing are slightly variable as well (cf. Figs 1, 7, 9, 11, and 13). Individual size varies as follows: wing span 18.5–22.2 mm, body length 10.8–13.1 mm, forewing length 8.4–10.0 mm, length of antenna 6.0–7.0 mm.

Comparison. Bembecia strandi seems to be the closest to B. sareptana . The male of B. strandi can be separated from the male of B. sareptana by the coloration of the frons (white to pale yellow with golden tint and admixture of several black scales medially in B. strandi , vs. dark brown to black with violet sheen and several yellow to pale yellow scales medially in B. sareptana ), tegula (black with greenish blue sheen, pale yellow spot with golden tint at base of forewing and dark yellow scales distally in B. strandi , vs. dark brown to black with greenish violet sheen in B. sareptana ; cf. Figs 7, 9, 11, and 13 in this article with figs 31, 33 and 35 in Gorbunov, 2018a or with figs 1, 3 and 5 in Gorbunov, 2020a), fore coxa (fore coxa pale yellow with golden tint and several black scales medially B. strandi , vs. fore coxa and femur dark brown to black with greenish sheen densely covered with dark brown hair-like scales in B. sareptana ; cf. Figs 8, 10, 12, and 14 in this article with figs 32, 34 and 36 in Gorbunov, 2018a or with figs 2, 4 and 6 in Gorbunov, 2020a), CuA –stem of the forewing dorsally (orange in B. strandi , vs. dark brown with greenish bronze sheen and several orange scales in B. sareptana ; cf. Figs 7, 9, 11, and 13 in this article with figs 31, 33 and 35 in Gorbunov, 2018a or with figs 1, 3 and 5 in Gorbunov, 2020a), as well as the conformation of the forewing (transparent areas rather well-developed, anterior transparent area divided into two parts by extremely narrow scaled line; posterior transparent area short, extends only slightly distal to level of discal spot of hindwing; external transparent area rather small, rounded distally, divided into five cells between veins R 3 and CuA 1, level to vein M 2 about 1.25 times as broad as discal spot and about 1.7 times as broad as apical area in B. strandi , vs. transparent areas well-developed; posterior transparent area slightly not reaching proximal margin of discal spot; external transparent area large, divided into five cells between veins R 3 and CuA 1, level to vein M 2 about 2.8 times as broad as discal spot and apical area in B. sareptana ; cf. Figs 7, 9, 11, and 13 in this article with figs 31, 33 and 35 in Gorbunov, 2018a or with figs 1, 3 and 5 in Gorbunov, 2020a). The female of B. strandi is distinguished from that of B. sareptana in the coloration of the frons and vertex (frons yellow-orange with golden tint and narrow black stripe with bright violet sheen laterally, vertex entirely orange in B. strandi , vs. frons dark brown to black with violet sheen and a large yellow-orange spot with golden hue medially, vertex black with dark violet sheen and an admixture of orange scales in B. sareptana ) and tegula (black with greenish blue sheen, pale yellow spot with golden tint at base of forewing and narrow yellow-orange inner margin in B. strandi , vs. dark brown to black with greenish violet sheen in B. sareptana ). In addition, these two species have slight differences in the shape of the valva and crista sacculi in the male genitalia and in the shape of the ostium bursae and the relative size of corpus bursae in the female genitalia (cf. Figs 15–20 in this article with figs 47–52 in Gorbunov, 2018a or with figs 11–16 in Gorbunov, 2020a).

Bembecia strandi differs from B. jakuta ( Herz, 1903) (unfortunately only males of this species are known at present) in the coloration of the frons (white to pale yellow with golden tint and admixture of several black scales medially in B. strandi , vs. dark grey-brown with several white scales medially in B. jakuta ), fore coxa (pale yellow with golden tint and several black scales medially in B. strandi , vs. black with blue-purple sheen, densely covered with black, long, hair-like scales in B. jakuta ), CuA –stem of the forewing dorsally ( CuA –stem orange in B. strandi , vs. black with dark violet sheen and several orange scales in B. jakuta ; cf. Figs 7, 9, 11, and 13 in this article with figs 1, 3, 5, and 7 in Gorbunov, 2025) and abdomen (dorsally: tergites 2, 4, 6, and 7 each with rather broad yellow stripe with golden tint distally; tergites 3 and 5 each with admixture of yellow scales with golden tint in distal half; ventrally: sternite 4 with broad yellow stripe with golden tint distally; basal sternite and sternites 5–7 each with admixture of yellow scales with golden tint distally; sternite 3 with several thin yellow-orange scales medially in B. strandi , vs. dorsally: tergites 4 and 7 each with rather broad yellow stripe with golden tint distally; tergite 2 with several pale yellow scales distally; tergite 6 with narrow yellow stripe distally; ventrally: sternite 4 with broad yellow stripe with golden tint distally; sternite 7 with narrow yellow stripe distally; sternites 5 and 6 each with several pale yellow scales both medially and distally in B. jakuta ; cf. Figs 7–14 in this article with figs 1–8 in Gorbunov, 2025). In addition, these two species differ significantly from each other in the structure of the transparent areas of the forewing (anterior transparent area divided into two parts by extremely narrow scaled line; posterior transparent area short, extends only slightly distal to level of discal spot of hindwing; external transparent area rather small, rounded distally, divided into five cells between veins R 3 and CuA 1, level to vein M 2 about 1.25 times as broad as discal spot and about 1.7 times as broad as apical area in B. strandi , vs. anterior transparent area well-developed, not divided into two parts by extremely narrow scaled line; posterior transparent area short, extends only slightly distal to level of discal spot of hindwing; external transparent area rather small, rounded distally, divided into five cells between veins R 3 and CuA 1, level to vein M 2 about twice as broad as discal spot and apical area in B. jakuta ; cf. Figs 7, 9, 11, and 13 in this article with figs 1, 3, 5, and 7 in Gorbunov, 2025) and the shape of the valva in the male genitalia (cf. Fig. 16 in this article with fig. 10 in in Gorbunov, 2025 or with text fig. 140 in Špatenka et al., 1999).

From B. bestianeli , which also has an anterior transparent area divided into two parts by an extremely narrow scaled line, B. strandi can be distinguished by the slightly more developed transparent areas of the forewing and the slightly different shape of the crista gnathi and crista sacculi in the male genitalia (cf. Figs 15 and 16 in this article with fig. 6A in Căpușe, 1973). It is appropriate to point out here that B. bestianeli is an insufficiently studied species and requires careful revision.

Bembecia strandi can be separated from B. turanica (Erschoff, 1874) by the coloration of the frons (white to pale yellow with golden tint and admixture of several black scales medially in B. strandi , vs. grey-brown with bronze sheen medially, laterally black with greenish violet sheen in B. turanica ) and abdomen (dorsally: tergites 2, 4, 6, and 7 each with rather broad yellow stripe with golden tint distally; tergites 3 and 5 each with admixture of yellow scales with golden tint in distal half; ventrally: sternite 4 with broad yellow stripe with golden tint distally; basal sternite and sternites 5–7 each with admixture of yellow scales with golden tint distally; sternite 3 with several thin yellow-orange scales medially; anal tuft dorsally black with greenish blue sheen and with several yellow-orange scales medially; anal tuft ventrally black with greenish violet sheen, medially yellow-orange in B. strandi , vs. dorsally: tergite 4 with rather broad yellow stripe with golden tint distally; tergite 2 with few white scales at distal margin; ventrally: sternite 4 with narrow yellow stripe with golden tint distally; anal tuft black with greenish sheen medially, orange laterally and with few yellow-orange scales ventromedially in B. turanica ; cf. Figs 7–14 in this article with figs 4–9 in Gorbunov & Ivanov, 2025). In addition, these two species have slight differences in the structure of the male genitalia (cf. Figs 15–19 in this article with figs 10–14 in Gorbunov & Ivanov, 2025).

Bembecia strandi can be separated from B. aktashica O. Gorbunov, 2018 by the coloration of the frons, fore coxa, legs and abdomen, as well as the conformation of the forewing and both the male and female genitalia (cf. the description and illustrations in this article with the description and figs 21–30 and 41–46 in Gorbunov, 2018a).

Bembecia strandi is clearly distinguished from all other congeners known from Russia by a combination of the colour signs of various parts of the body and by the structure of the male and female genitalia.

Distribution. Currently, B. strandi is known only from Tagarskiy Island near Minusinsk (Krasnoyarsk Territory of Russia).

Bionomics. The larval host plant is unknown. Adults occur from the second half of June to the first half of August. Males are attracted to pheromones in the first half of the day, between approximately 9 a.m. and 1 p. m.

Habitat. The new material was collected on the mixed-grass meadow–steppe, where representatives of the legume family were very common and diverse (See Addenda: Fig. 21).