Dioctria aestivis Esipenko

Young, Charles L. & Hradský, Milan M., 2008, Robber flies (Diptera: Asilidae) of South Korea. Parts VI – VIII. South Korean species of the Subfamilies Dasypogoninae, Dioctriinae and Trigonomiminae, Zootaxa 1876, pp. 1-18 : 5-8

Dioctria aestivis Esipenko

( Figs 1–5 )

Dioctria aestivis Esipenko 1970: 42 .

Dioctria stackelbergi Esipenko, 1971: 194 ( Lehr, 1999: 627) .

Medium sized dark, slender delicate flies, 11–12 mm. Dioctria aestivis is distinguished from the other species of the genus Dioctria from South Korea by the distinct black bands on the hind femur and tibia, the other species with less distinct markings. As noted by Lehr (2001), “Wide variability in external characters is typical of the species.” This particularly holds true for the wing pigmentation and coloring on the abdomen in our South Korean specimens (see “Variation” below).

Adult. Male.

Head. Upper face shining black, sparse yellow tomentum ventrally and fine silver tomentum laterally. Mystax semicircular in shape, with sparse long yellow/white hairs. Relative length of antennal segments: 3 + 4<1<2. 1st antennal segment less than or 2 times as long as segment 2. Thorax shining black with sparse, short yellow/gold hair and tomentum. Stripe of yellow/gold tomentum on pleurae complete, running ventrally up from anterior margin of katepisternum, dorsally and laterally along anepisternal margins, terminating on posterior margin of katepisternum. Anterior margin of postpronotum lobe with orange stripe, lateral apex with small orange spot. Median and paramedian stripes of scutum well defined, yellow/gold tomentum stripes Chaetotaxy with: 2 presutural and 4 supraalar yellow bristles; postalar callus with sparse gold hair. Scutellum broadly wrinkled with sparse fine yellow/gold hair. Legs yellow and black with fine sparse yellow bristles. Coxae black with fine silver/gray tomentum and longer fine white hair. Fore and mid legs yellow; tarsomeres black. Hind femur with broad black band, apex yellow. Hind tibia black, basal apex yellow. Wing: Tinged black on basal half, apical half less so. Abdomen: Yellow with black apical bands and sparse yellow hair. Tergite 1 entirely black; tergites 2, 3, 4 yellow with black apical bands; tergite 5 gradually wider from base to apex; apical 2/3 black; tergite 6 entirely black; tergite 7 black on basal 2/3, apex yellow. Male genitalia ( Figs 1–5 ) yellow. Gonopod ( Figs 3–5 ) wide basally; apically ( Fig. 5 ) gonostylus lobate. Aedeagus stout, truncated with 2 slender endoaedeagi.

Female. Similar to male except wings less pigmented. Tergites 7, 8 dark yellow. Genitalia. Cerci brown, medially divided with dark with yellow/gold stiff hair.

Variation. Wings may be darkly pigmented to clear. Abdominal apical black bands may appear as spots of various shapes, surrounded by yellow.

Material examined. Chollabuk Province. 1 Ψ: 20/VI/1999, Naejangsan Mt. N. P., 35°26’34”N, 126°53’06”E. 1 Ψ: 15/VI/2003, Chiri Mt. Piakol, 35°15’57”N, 127°34’52”E.

Kangwon Province. 1 ɗ: 24/VI/2006, Nam Myon, Hongcheon R. (east), 37°42’40”N, 127°35’26”E.

Field notes. All specimens except the single female collected on Naejangsan Mt. were collected in Malaise traps using 95% ethanol. Prey: Hymenoptera. See also table 1 on prey and seasonality.

Dioctria humeralis eoa Lehr, 1965: 194 .

Medium sized dark, slender delicate flies, 7.0–10.1 mm. Dioctria humeralis eoa is distinguished from South Korean congeners by the 1st antennal segment which is 2 times as long as segment 2, and the medially spotted wings.

Adult. Female.

Head. Upper face shining black, below and laterally micropubescent. Mystax a semicircle of sparse yellow hairs. Relative lengths of antennal segments: 3 + 4<1<2. 1st antennal segment 2 times as long as segment 2. Thorax black with abundant yellow micropubescence and sparse, short, yellow hair. Stripe of yellow/gold tomentum on pleurae compete, running ventrally up from anterior margin of katepisternum, dorsally and laterally along anepisternal margins, terminating on posterior margin of katepisternum. Postpronotum and postalar callus laterally yellow. Median stripe of scutum well defined: yellow pubescent against black integument. Chaetotaxy with: 1 presutural and 3 weak yellow supraalar bristles; postalar callus with sparse gold hair. Scutellum broadly wrinkled with sparse fine yellow/gold hair. Legs yellow with fine sparse yellow bristles. Coxae yellow with fine white hair. Fore and hind tibiae with pale tan markings medially and apically. Wing medially spotted, sometimes entirely clear. Abdomen: Blue/black with yellow apical bands and sparse, fine, yellow hair. Tergite 1 entirely black; base of tergites 2, 3 with yellow triangular markings laterally; tergites 4– 8 with thin, yellow, apical bands. Female cerci yellow, apices with tan spots and long tufts of yellow hair.

Male. Unknown.

Variation. Wings may not show medial spot. Yellow tergite apical bands may be absent, or only faintly visible on tergites 4–6, giving the abdomen an overall black appearance.

Material examined. Chungchongbuk Province. 2 ΨΨ: 14–17/VIII/1996, Taejon. P. Tripotin coll. 1 Ψ: 21/ VI/1996, Taejon, Wadong, P. Tripotin coll.

Kangwon Province. 1 Ψ: 1/VIII/1997, “Hambaeksan near T’aebaeksan, 1400m.,” P. Tripotin coll.

Field notes. All specimens were collected in Malaise traps using 95% ethanol. No recorded prey. See also table 1 on prey and seasonality.

Figures

FIGURE 1 – 5. Dioctria aestivis, male genitalia. 1, lateral; 2, ventral; 3, gonopod, ventral; 4, gonopod, dorsal; 5, gonostylus.