Epistrophe annulitarsis ( Stackelberg, 1918 )

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 : 213-215

3. Epistrophe annulitarsis ( Stackelberg, 1918)

ḏṣḇHqỵỄOi (ljḑ) ( Figs. 1K- O , 4I- L )

Syrphus annulitarsis Stackelberg, 1918: 2155 (type locality - Russia, Novgorod, SE of Leningrad; holotype ♂, ZISP); Violovitsh, 1983: 41 (in Siberian key).

Epistrophe annulitarsis : Hippa, 1968: 23 (redescription); Vockeroth, 1969: 60 (in Syrphini generic revision); Peck, 1988: 19 (in Palaearctic catalog); Ȏhara, 1989: 783 (in Japanese checklist); Huang et al., 1996: 142 (in Chinese checklist); Mutin and Barkalov, 1999: 382 (in Russian Far East key); Hua, 2006: 73 (in Chinese checklist); Ichige, 2007: 37 (redescription); Huang and Cheng, 2012: 182 (redescription); Ȏhara et al., 2014: 468 (in Japanese catalog); Barkalov and Mutin, 2018: 495 (in Russian checklist); Huo in Yang et al., 2020: 152 (in Chinese catalog).

Diagnosis. Epistrophe annulitarsis can be readily distinguished from Korean congeners by the following characteristics: 1) hind tarsus pale yellow to pale brown with 6 blackish ringlets (basal and apical ringlets on 1st tarsomere plus apical ringlet on each of 2-5th tersomeres) ( Fig. 1M, O ); 2) sternites 2 and 3 each with pair of narrow semicircular black spots on lateral margins ( Fig. 1L ); and 3) basiphallus with 2 pairs of pointed ventral processes ( Fig. 4 K-a, -b, L).

Description of Korean material. Male. Lengths and ratios: body length 10.6-11.7 mm; wing length 9.4-10.4 mm; head ratio 0.69-0.73; face ratio 0.41-0.44; eye ratio 0.52-0.56; gena-eye ratio 0.06-0.07; antenna-head ratio 0.39-0.41; postpedicel-pedicel ratio 2.00-2.50; arista-antenna ratio 1.06-1.26; wing ratio 3.33-3.62; wing-thorax ratio 2.48-2.69; vein M ratio 2.20-2.83; vein R 4+5 ratio 3.14-3.94. Head holoptic with eye contiguity slightly shorter than vertical triangle ( Fig. 1K ); compound eye dark brown with slight purplish tinge, bare; vertex black, anteriorly with slightly wavy black hairs, posteriorly with brownish-yellow hairs (sometimes largely with slightly wavy black hairs and postero-marginally mixed with some brownish-yellow hairs); frons anteriorly brownish yellow, posteriorly black, largely with yellowish grey to yellow pruinosity except for anterior margin, with black hairs; lunule brownish yellow, bare (sometimes dorso-medially with small blackish spot); antenna largely brownish yellow to pale brown except for variably darkened dorsal area of postpedicel ( Fig. 1M ); face almost entirely brownish yellow to yellow ground color except for pair of small brownish black lateral spots on lower facial margin ( Fig. 1 M-a), with greyish pruinosity, and with wavy brownish-yellow hairs; facial knob rounded, almost bare; gena pale yellow to brownish yellow with greyish pruinosity, and with brownish-yellow hairs ( Fig. 1M ). Thorax largely blackish with yellowish grey to yellow pruinosity, with wavy brownish yellow to pale yellow hairs ( Fig. 1K ); scutum with subshiny yellowish grey pruinosity; medial scutal area with pair of longitudinal greyish pruinose stripes (can be observed under appropriate lighting), interrupted at anterior 3/5-2/3; lateral margins of scutum matte yellow ( Fig. 1K, M ); scutellum brownish yellow, largely with wavy black hairs, but anterior to lateral side with wavy brownish-yellow hairs (sometimes brownish-yellow haired area larger than black haired area); pleura blackish, mostly with yellowish pruinosity ( Fig. 1M ); anterior anepisternum, anterior 1/3-1/2 of posterior anepisternum, dorsomedial anepimeron, posterior anepimeron, meron, anatergite, mediotergite and metasternum bare; katepisternum with upper and lower brownish yellow hair patches, narrowly connected on posterior margin; halter with stem brownish yellow to pale yellow, knob yellow to brownish yellow. Legs with variable colored coxae (pale yellow to brownish black) with brownish yellow hairs ( Fig. 1M ); trochanters brownish yellow with brownish yellow hairs; femora brownish yellow with brownish yellow hairs (hind femur antero-apically with short black hairs); fore and mid tibiae brownish yellow with short brownish yellow hairs; hind tibia brownish yellow to pale brown, subapically slightly darkened, largely with short black hairs but apico-ventrally with brownish yellow hairs; fore and mid tarsi brownish yellow with short brownish yellow hairs (sometimes a few short black hairs sparsely mixed); hind tarsus pale yellow to pale brown with 6 blackish ringlets (basal and apical ringlets on 1st tarsomere plus apical ringlet on each 2-5th tarsomeres), dorsally with short black hairs, ventrally with short brownish yellow hairs. Wing largely hyaline with slight pale brownish tinge ( Fig. 1M ); veins pale brown to brownish black; pterostigma pale brown; cell sc before pterostigma yellowish; wing membrane entirely microtrichose (sometimes with narrow bare area on baso-anterior margin of cell br); upper and lower calypters pale yellow to brownish yellow with long brownish yellow marginal hairs. Abdominal tergites unmargined, brownish yellow ground color with black markings, with wavy brownish yellow and black hairs (wave getting weaker towards apex) ( Fig. 1K ); tergite 1 largely subshiny black except for brownish yellow antero-lateral area (occasionally brownish yellow area covering half or more area); tergite 2 with black transverse antero- and postero-marginal band narrowly connected with narrow longitudinal mid-stripe (stripe occasionally missing), black antero-marginal band medio-posteriorly larger, black postero-marginal band anteriorly slightly undulated; tergite 3 with narrow black transverse postero-marginal band, anteriorly slightly undulated; tergite 4 with narrow black subposterior band, anteriorly slightly undulated; tergite 5 brownish yellow, medially with variable sized black spot of less than 1/5 of tergite width; sternite 1 pale yellow with wavy pale yellow hairs; sternites 2 and 3 pale yellow, each with pair of narrow semicircular black spots on lateral margins ( Fig. 1L ), largely with wavy pale yellow to brownish yellow hairs, postero-laterally mixed with a few black hairs (black hairs more on sternite 3 than on sternite 2); sternites 4-7 pale yellow to pale brown with black and brownish yellow hairs variably mixed; sternite 8 brownish yellow to pale brown with rounded blackish spot of about 2/5-3/4 of sternite width, with brownish yellow hairs. Male genitalia ( Fig. 4I- L ) with epandrium as long as height in lateral view ( Fig. 4J ); surstylus relatively short, slightly longer than width in caudal view (middle width about 4/5 of length when oriented to show broadest area) ( Fig. 4I ), slightly curved anteriorly with rounded apex in lateral view, basally with long brownish yellow hairs, apically with short hairs ( Fig. 4J ); hypandrium with slightly up-curved lingula ( Fig. 4J ); lateral protuberance of hypandrium slightly longer than lingula, with slightly down-curved and rounded apex; distiphallus apically slightly widened in lateral view; about apico-ventral 3/5 of distiphallus densely with short spiny hairs ( Fig. 4K ); basiphallus with 2 pairs of pointed ventral processes ( Fig. 4 K-a, -b, L). Female. Similar to male except for the following characteristics. Lengths and ratios: body length 9.8-11.9 mm; wing length 8.7-10.6 mm; head ratio 0.68-0.76; face ratio 0.39-0.43; eye ratio 0.52-0.59; gena-eye ratio 0.05-0.07; antenna-head ratio 0.44-0.50; postpedicel-pedicel ratio 2.09-2.40; arista-antenna ratio 1.11- 1.16; wing ratio 2.86-3.53; wing-thorax ratio 2.59-2.82; vein M ratio 2.43-3.07; vein R 4+5 ratio 3.27-3.62. Head dichoptic with vertex about 0.17 × as wide as head in dorsal view ( Fig. 1N ); anterior 1/6-1/5 of frons brownish yellow, posterior 4/5-5/6 black; lateral margins of frons heavily with yellow to yellowish grey pruinosity, each of about 2/5 of shortest width of frons, except for median and posterior 1/3 areas. Thorax ( Fig. 1N ): scutal pruinosity with more greyish tinge; Wing membrane with larger basal bare areas than in males (especially, baso-anterior margin of cell br, along the posterior of vein CuP of cell cup, and occasionally baso-anterior margin of cell bm). Abdominal tergites: black transverse antero- and postero-marginal bands on tergite 2 separated ( Fig. 1N ) (these bands occasionally slightly connected as in males); black transverse bands on tergites 3 and 4 almost straight (less undulated than that of male - Fig. 1K vs. N). Material examined. KOREA: Chungchengnam-do: Geumsan-gun, Nami-myeon, Bohyeonsa Temple, N36° 03.494 ʹ E127°27.225 ʹ, 14.V-1.VI.2005, P. Tripotin, 3$; Gangwon-do: Hoengseong-gun, Dunnae-myeon, Sapgyo-ri, Mt. Cheongtaesan, N37°30 ʹ 40 ʺ E128°18 ʹ 01 ʺ, 15. VIII.2001, D.-S. Choi et al., 1$(NIBR); Hongcheon-gun, Nae-myeon, Bangnae-ri, N37°51 ʹ 11 ʺ E128°16 ʹ 52 ʺ, 9.IX.2016, S.-S. Euo, C.-O. Kim, W.-R. Ha, 3♂, 2$; Hongcheon-gun, Nae-myeon, Changchon-ri, north valley of Mt. Gyebangsan, N37°44 ʹ 39 ʺ E128°26 ʹ 58 ʺ, 14. VIII.1998, H.-Y. Han, K.-E. Ro, 1$; Hongcheon-gun, Nae-myeon, Gwangwon-ri, Woldoon-gol, N37°50 ʹ 52 ʺ E128°25 ʹ 24 ʺ, 16.IX.2017, S.-S. Euo, C.-O. Kim, J.-H. Choi, 3$; ditto, 1.IX.2019, S.-S. Euo, C.-O. Kim, 1♂; Hongcheon-gun, Nae-myeon, Mt. Gyebangsan, Unduryeong, N37°43 ʹ 41 ʺ E128°27 ʹ 55 ʺ, 23.VIII.2001, D.-S. Choi, H.-S. Lee, S.-H. Kim, 1♂; Hongcheon-gun, Seo-myeon, Magok-ri, N37°42.97 ʹ E127°35.45 ʹ, 24.VIII-31. IX.2006, P. Tripotin, 1♂; ditto, 4.V-6.VI.2006, P. Tripotin, 1$; Hwacheon-gun, Sanae-myeon, Gwangdeok-ri, Mt. Gwangdeoksan, 29.VIII.2000, C.-H. Park, D.-W. Kim, 2$; Jeongseon-gun, Gohan-eup, Mt. Hambaeksan, Manhang-jae, N37°8 ʹ 53 ʺ E128°54 ʹ 14 ʺ, 29.VIII.2000, H.-Y. Han, K.-E. Ro, 1♂; Pyeongchang-gun, Bangrimmyeon, Ungyo-ri, N37°26 ʹ 17.18 ʺ E128°19 ʹ 11.7 ʺ, 24.IX. 2010, S.-W. Suk et al., 1♂; Pyeongchang-gun, Yongpy- eong-myeon, Nodong-ri, Nodong Valley (900 m), N37° 42.08 ʹ E128°28.89 ʹ, 31.V-5.VI.2006, P. Tripotin, 1$; ditto, 26.VIII-1.X.2006, P. Tripotin, 1♂, 1$; Samcheok-si, Dogye-eup, Mugeon-ri, Moss waterfall, N37°15 ʹ 32.6 ʺ E129°06 ʹ 34.8 ʺ, 17.IX.2019, S.-S. Euo, C.-O. Kim, 1$; Samcheok-si, Geunsan-dong, Mt. Geunsan, N37°24 ʹ 48 ʺ E129°08 ʹ 29 ʺ, 28.IV.2018, S.-S. Euo, C.-O. Kim, J.-H. Choi, 2♂.

Distribution. Russia, Korea, China, Japan, widespread in Europe.

Biology. This species has been often observed while feeding on flowers in the foothills of mountains in Korea.

Remarks. The examined Korean specimens agree well with the original description ( Stackelberg, 1918) as well as the redescriptions including male genitalia characters ( Hippa, 1968; Ichige, 2007). The new Korean name translates as “ Epistrophe fly with spotted foot” referring to its black ringlets on the hind tarsus.

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.