Epistrophe grossulariae (Meigen)
Epistrophe grossulariae (Meigen, 1822).
Meigen, J.W. (1822) Systematische Beschreibung der bekannten europaischen zweiflugeligen Insekten. Dritter Theil. Schulz-Wundermann, Hamm. x + 416 pp., pls. 22-32.
Epistrophe species usually have dorsal and ventral pile patches of the katepisternum narrowly joined posteriorly and tergum 4th with a yellow fascia, or with linear grey maculae or entirely black.
Adapted from Vockeroth (1992).
Head: Frons yellow-gray pollinose on dorsal half to three-fifths, shining brownish black on ventral half to two-fifths, usually yellowish anteromedially. Face pale yellow, usually with narrow obscure brownish
medial vitta on ventral three-fIfths. Antenna black, scape yellowish below in some specimens.
Thorax: Scutellar pile almost all black. Metasternum with many long pale pile. Wing membrane entirely microtrichose. Metacoxa with posteromedial apical pile tuft and with many black pile. Procoxa yellow to yellow-brown, meso- and metacoxae brown to black. Pro- and mesofemora with up to basal one-fifth, and metafemur with up to basal half, brown to black; femora otherwise yellow.
Abdomen: Tergum 2 with pair of large pale yellow maculae regularly broadened laterally and extending over anterior half to two-thirds of margins; terga 3 and 4 each with rather long anterior yellow fascia, in some specimens emarginate posteriorly and reaching the margins in its full width; tergum 4 broadly yellow posteriorly; margins of terga 2-4 alternately yellow and black. Posterior half of sternum 3 and
all sternum 4 with both long suberect and short appressed pile black.
Frons mostly yellow-gray pollinose, area around ocelli and narrow to broad medial vitta dark, subshining brownish black only above antennae. Metafemur commonly entirely yellow posteriorly. Markings of tergia submetallic gray rather than yellow in some specimens.
Body length: 10.4-15.0 mm.
Ecology and Distribution
This species ranges from Fennoscandia south to Spain; from Ireland eastwards through Eurasia to Kamchatka; Italy; the former Yugoslavia and Turkey. It is also found across North America from Alaska to Quebec and south to California and Colorado.
Adults' preferred environment: deciduous forest, particularly along rivers and streams, including Salix swamp woodland; also alpine grassland.
Chambers et al. (1986) refer to having collected larvae of this species from winter wheat crops.
Flowers visited by adults: white umbellifers; Centaurea, Cirsium, Filipendula, Geranium, Knautia, Rhododendron, Rubus, Sambucus nigra, Succisa, Valeriana.
Larvae have been reported feeding on Anoecia corni, Anuraphis farfarae, Brevicoryne brassicae, Drepanosiphum platanoidis, Dysaphis plataginea, Eriosoma patchiae, Hyalopterus pruni, Metopolophium dirhodum, Myzus persicae and Sitobion avenae (Aphididae) (Rojo et al. 2003).
Flight period for Europeans individuals: end June/September, with males predominating in June and females continuing on into September (Speight 2010).
Adults inhabit clearings, tracksides and beside streams etc.; adults fly at up to 3 m.; males hover at 2-5 m over tracks etc.
Larva of E. grossulariae was described and figured by Rotheray (1986) and figured in colour by Rotheray (1994), from larvae collected on Acer pseudoplatanus. Dixon's (1960) material identified as E. grossulariae was wrongly determined (Rotheray 1986).
Larva (from Rotheray 1986).
Length 11-15 mm, width 3.5-5.5 mm, height 1.5-2 mm; dorso-ventrally flattened, smooth and ovate in outline; green and uniformly flecked white, turning opaque and orange-brown during diapause; a white or cream mid-dorsal stripe present which partially disintegrates on the posterior half of the body to form a chain-link like pattern. Segmental setae short and mounted on small protuberances. lntegumental vestiture absent but dorsal surface covered with numerous oval shaped papillae; these are largest on the dorsal mid-line and are absent on the ventral surface. Ventral surface flat without raised locomotory prominences. Posterior respiratory process approximately as long as basal width; basal half without nodules or nodular at extreme base only; dorsal spurs well developed; second spiracular slit closer to third than the first; first and third spiracular slits diverging by almost 180º. Description based on approximately 50 larvae from Cardiff, S. Wales; West Kirby, Merseyside; and Edinburgh, Scotland.
Puparium: pale brown; inflated anteriorly and concave posteriorly; posterior respiratory process approximately as long as basal width.
Evolution and Systematics
Nomenclature and Synonymy
Syrphus grossulariae Meigen, 1822: 306.
Syrphus lesueurii Macquart, 1842: 152.
Epistrophe conjugens Walker, 1852: 242.
Syrphus melanis Curran, 1922: 96.
Musca formosus Harris, 1780: 107.
Epistrophe is a very diverse genus in adult morphology. Although the adults are similar to Syrphus, they have completely different larval morphology. The cladistic analyses of Rotheray and Gilbert (1989) placed Epistrophe with Epistrophella, and Meligramma together with Parasyrphus or with Xanthogramma and Doros (Rotheray and Gilbert, 1999). Fluke (1950) transferred species from Epistrophe to Stenosyrphus (junior synonym of Melangyna) and placed Epistrophe as subgenus of Syrphus. Wirth et al. (1965) recognized Epistrophe as a separate genus from Stenosyrphus. Dusek and Laska (1967) followed Wirth et al. (1965) and created a new genus for Syrphus euchromus Kowarz, 1885, Epistrophella.
Vockeroth (1969) indicated the unusual variation in thoracic and abdominal markings of Epistrophe and suggested to use the two subgenera: Epistrophe s.s. and Epistrophella. The analyses of larval morphology guided Rotheray and Gilbert to synonymize Epistrophella under Meligramma. Results by Mengual et al. (2008) suggested that Epistrophella is close to Xanthogramma, in agreement with larval evidence (Rotheray and Gilbert, 1999), close to the clade of Epistrophe but not placed in the same clade with Meligramma. This molecular analysis also indicated that Allograpta is not related with Epistrophe as suggested by Hull (1949) who could not find any valid distinctions except upon the abdominal pattern, and the relationship between Meligramma and Epistrophe is not close as larval evidence suggests.