Epistrophe aeka Kimura, 1989

Kim, Chan-Ouk, Hwang, Seul-Ma-Ro & Han, Hak-Seon Lee and Ho-Yeon, 2022, Ten species of the tribe Syrphini (Insecta: Diptera: Syrphidae) newly recorded in Korea, Journal of Species Research 11 (3), pp. 208-237 : 209-211

1. Epistrophe aeka Kimura, 1989

jšģHqỵỄOi (ljḑ) ( Figs. 1A- F , 4A- D )

Epistrophe aeka Kimura, 1989: 1 (type locality - Japan, Kyoto; holotype ♂, KPU; paratypes 8♂ same data as holotype, TKPM); Schmid, 1995: 31 (in Palaearctic list); Ȏhara et al., 2014: 467 (in Japanese catalog).

Diagnosis. Epistrophe aeka is a relatively small (8.20 mm) species in the genus having a predominantly blackish body. It can be readily distinguished from Korean congeners by the following combination of characteristics: 1) compound eye densely covered with long brown hairs ( Fig. 1D ); 2) face with brownish-black vertical facial stripe ( Fig. 1D ); 3) gena brownish black and wide (over 0.25 × as long as eye height) ( Fig. 1C, F ); 4) pterostigma largely dark brown but apically paler ( Fig. 1A, E ); and 5) basiphallus only with single pair of wide and slightly serrated apico-ventral processes ( Fig. 4 C-b, D-b). The above characteristics 1 and 5 especially are only observed in this species among Korean Epistrophe .

Description of Korean material. Male. Lengths and ratios: body length 8.20 mm; wing length 7.93 mm; head ratio 0.76; face ratio 0.64; eye ratio 0.64; gena-eye ratio 0.30; antenna-head ratio 0.48; postpedicel-pedicel ratio 2.11; arista-antenna ratio 0.91; wing ratio 3.31; wing-thorax ratio 2.56; vein M ratio 2.60; vein R 4+5 ratio 3.92. Head holoptic with eye contiguity slightly shorter than vertical triangle ( Fig. 1A ); compound eye dark brown with slight purplish tinge, densely covered with relatively long brown hairs ( Fig. 1D ); vertex black with slightly wavy brownish-yellow hairs; frons black almost entirely with yellowish pruinosity except for bare anterior margin, with slightly wavy brownish yellow and brownish black hairs mixed approximately at 1: 2 ratio ( Fig. 1A, D ); lunule largely brownish black except for dark brown medio-ventral and latero-ventral margins, bare; antenna brownish black; face largely brownish yellow ground color with yellowish grey pruinosity, with wavy brownish-yellow hairs, and with brownish-black vertical facial stripe from lower facial margin up to area below antennal sockets, about 0.46 × as wide as facial width ( Fig. 1D ); facial knob rounded, almost bare; gena brownish black with yellowish grey pruinosity, and with wavy brownish-yellow hairs ( Fig. 1C ). Thorax largely blackish with greyish pruinosity, except for brownish yellow scutellum (baso-ventral corners of scutellum brownish black), with wavy brownish-yellow hairs ( Fig. 1A ); scutum with 4 narrow longitudinal subshiny bluish-grey pruinose stripes on paramedial and latero-marginal area, connected postero-marginally (detectable in better prepared specimens); medial scutal area between 2 inner bluish stripes with pair of longitudinal greyish pruinose stripes (can be observed under appropriate lighting) interrupted at anterior 3/4; pleura blackish, mostly with greyish pruinosity ( Fig. 1C ); anterior anepisternum, anterior 1/3 of posterior anepisternum, dorsomedial anepimeron, posterior anepimeron, meron, anatergite, mediotergite and metasternum bare; katepisternum with upper and lower wavy brownish-yellow hair patches, narrowly connected on posterior margin; halter with stem brown to pale yellow, knob brownish yellow. Legs with coxae and trochanters brownish black with brownish-yellow hairs ( Fig. 1C ); femora largely brownish black except for brownish-yellow apex, with brownish-yellow hairs (hind femur apically mixed with short black hairs); fore and mid tibiae largely brownish yellow but apical half slightly darkened, with short brownish-yellow hairs; hind tibia about basal 2/5 brownish yellow, about apical 3/5 dark brown to brownish black, largely with short black hairs but ventrally with short brownish-yellow hairs; fore and mid tarsi dorsally pale brown to brown, ventrally brown to dark brown, largely with short brownish-yellow hairs but some short black hairs sparsely mixed; hind tarsus dorsally dark brown to brownish black with short black hairs, ventrally brown with short brownish-yellow hairs. Wing largely hyaline with slight pale brownish tinge ( Fig. 1A ); veins pale brown to dark brown; pterostigma largely dark brown but apically paler; cell sc before pterostigma yellowish; wing membrane largely covered with microtrichiae except for basal bare areas; upper and lower calypters brownish yellow with long brownish-yellow marginal hairs. Abdominal tergites unmargined, black ground color with yellowish markings on tergites 2 and 3, with wavy brownish-yellow hairs (wave getting weaker towards apex) ( Fig. 1B ); tergite 1 subshiny black with greyish pruinosity; tergite 2 antero-lateral marginally with pair of subquadrate yellowish spots (about 2/3 as long as tergite) reaching lateral margins, medio-posterior margin narrowly brownish yellow; tergite 3 subanteriorly with narrow brownish yellow transverse band separated from lateral margins, posterior margin narrowly brownish yellow; tergites 4 and 5 entirely brownish black to black; sternites 1 and 2 yellowish with wavy pale yellow hairs; sternites 3-8 dark brown to brownish black with pale yellow to brownish-yellow hairs. Male genitalia ( Fig. 4A- D ) with epandrium slightly longer than height in lateral view ( Fig. 4B ); surstylus long in caudal view (middle width about 2/5 of length when oriented to show broadest area) ( Fig. 4A ), slightly curved anteriorly with rounded apex in lateral view, basally with long brownish-yellow hairs, apically with short hairs ( Fig. 4B ); hypandrium with almost straight lingula ( Fig. 4B ); lateral protuberance of hypandrium longer than lingula, with rounded apex; distiphallus apically widened as trumpet shape in lateral view ( Fig. 4C ); apico-dorsal lip of distiphallus about 1/4 of apex width, narrow ( Fig. 4 C- a); about apico-ventral 1/3 of distiphallus densely with short spiny hairs ( Fig. 4C ); basiphallus only with single pair of wide and slightly serrated apico-ventral processes ( Fig. 4 C-b, D-b). Female. Similar to male except for the following characteristics. Lengths and ratios: body length 6.80-9.60 mm; wing length 6.00- 8.47 mm; head ratio 0.73-0.74; face ratio 0.55-0.56; eye ratio 0.55- 0.6; gena-eye ratio 0.25-0.28; antenna-head ratio 0.52- 0.54; postpedicel-pedicel ratio 2.30-2.57; arista-antenna ratio 0.90-0.93; wing ratio 3.33-3.34; wing-thorax ratio 2.61-2.65; vein M ratio 3.00-3.20; vein R 4+5 ratio 3.72- 3.73. Head dichoptic with vertex about 0.19 × as wide as head in dorsal view ( Fig. 1E ); vertex black, largely with slightly wavy brownish-yellow hairs but anteriorly mixed with some black hairs; brownish-black vertical facial stripe about 0.33-0.39 × as wide as facial width. Abdominal tergite 1 medio-posteriorly brownish yellow; yellowish spots on tergite 2 distinctly wider, covering almost entire width of tergite ( Fig. 1B vs. E); tergite 4 subanteriorly with narrow brownish-yellow transverse band (occasionally interrupted in middle), posterior margin narrowly brownish yellow ( Fig. 1 E-a).

Material examined. KOREA: Gangwon-do: Wonju-si, Gwirae-myeon , Mt. Sibjabong from Cheoneunsa Temple , N37°13 ʹ 34 ʺ E127°54 ʹ 36 ʺ, 5.V.2005, H.-W. Byun et al., 1$; Wonju-si , Heungeop-myeon , Maeji-ri , Yonsei Univ. Mirae Campus, N37°17 ʹ 10 ʺ E127°54 ʹ 01 ʺ, 31.V.2005, D.-S. Choi et al., 1♂ ( NIBR); Pyeongchang-gun, Jinbu-myeon, Jangjeon-ri, Jangjeon Valley , N37°27 ʹ 59.2 ʺ E128°32 ʹ 18.7 ʺ, 14.VI.2021, C.-O. Kim, M.-H. Park, 1 $. JAPAN: Ibaraki Pref., Mito C., Forest Park , N36°25.2 ʹ E140°22.2 ʹ, 14.VI.2002, K. Ichige, 3♂; ditto, 26.IV.2006, K. Ichige, 1 $.

Distribution. Japan (Honshu and Kyushu), Korea.

Biology. This species is known to visit Prunus and Acer trees in Japan ( Kimura, 1989).

Remarks. The three available Korean specimens agree well with the original description ( Kimura, 1989) as well as four Japanese specimens donated by Katsuyoshi Ichige. The new Korean name of this species translates as “small and black Epistrophe fly” referring to its small body size and dark coloration.

Figures

Fig. 1. A-F.Epistrophe aeka Kimura, 1989: (A, C) male body, dorsal and lateral view; (B) male abdomen, dorsal view (reconstructed from Fig. 1A); (D) male head, frontal view; (E, F) female body, dorsal and lateral view. G-J. Epistrophe aino (Matsumura, 1917): (G, H) male body, dorsal and lateral view; (I, J) female body, dorsal and lateral view. K-O. Epistrophe annulitarsis (Stackelberg, 1918): (K, M) male body, dorsal and lateral view; (L) male abdomen, ventral view;(N, O) female body, dorsal and lateral view. Voucher specimen codes:A-D - EpiAek_M1; E, F - EpiAek_F1; G, H - EpiAin_M4; I, J - EpiAin_F2; K, M - EpiAnn_M2; L - EpiAnn_M3; N, O - EpiAnn_F1.

Fig. 4. Male genitalia. A-D. Epistrophe aeka Kimura, 1989: (A) caudal view; (B) lateral view; (C) aedeagus, lateral view; (D) basiphallic ventral processes, ventral view. E-H. Epistrophe aino (Matsumura, 1917):(E) caudal view; (F) lateral view; (G) aedeagus, lateral view; (H) basiphallic ventral processes, ventral view. I-L. Epistrophe annulitarsis (Stackelberg, 1918):(I) caudal view; (J) lateral view;(K) aedeagus, lateral view; (L) basiphallic ventral processes, ventral view. Scale bars: 0.3 mm. Voucher specimen codes: A-D - EpiAek_F1; E-H - Epi- Ain_M5; I-L - EpiAnn_M3.