Egle minuta ( Meigen, 1826 )

Michelsen, Verner, 2009, Revision of the willow catkin flies, genus Egle Robineau-Desvoidy (Diptera: Anthomyiidae), in Europe and neighbouring areas, Zootaxa 2043 (1), pp. 1-76 : 53-56

19. Egle minuta ( Meigen, 1826)

Figs. 152–157 , 197 .

Anthomyia minuta Meigen, 1826: 177 .

‘ Egle parva Robineau-Desvoidy’; Schnabl & Dziedzicki 1911: 105, plate figs. 247, 248, 779;? Frey 1916: 692. Misidentification.

Hylemyia fuscohalterata Malloch, 1920b: 279 , figs. 6, 22. Synonymized by Xue et al. (1998: 660).

Hylemyia (Egle) tantalisa Huckett, 1928: 76 , fig. 5. Synonymized by Xue et al. (1998: 660).

‘ Egle atomaria (Zetterstedt) ’; Ringdahl 1933: 29 (in part); Karl 1934: 93, fig. 2; Tiensuu 1936: 14; Karl 1937: 139; Ringdahl 1951: 153 (in part). Misidentification.

‘ Hylemyia (Egle) ? parva (Robineau-Desvoidy) ’; Ringdahl 1939a: 45. Misidentification.

‘ Egle ? atomaria (Zetterstedt) ’; Ringdahl 1957: 101. Misidentification.

Egle minuta (Meigen) ; Collin 1947: 33; Lyneborg 1965: 220 (in part); Hennig 1967a: 140, text fig. 134, plate figs 137, 149, 154; Ackland 1970: 188, 192, figs. 15, 16; Suwa 1974: 90, figs. 234–237; Hennig 1976: 937, 938; Ackland & Pont 1977: 442; Hackman 1980: 132; Barták & Rozkošný 1984: 74; Barták et al. 1989: 316; Barták et al. 1990: 446; Draber-Moṅko 1991: 234; Ólafsson 1991: 55; Dely-Draskovits 1993: 52; Chandler 1998: 166; Michelsen & Merz 1998: 314; Xue et al. 1998: 660, fig. 1476; Suwa 1999: 221; Teschner 1999: 131; Petersen 2001: 184; Michelsen & Báez 2002: 201; Michelsen 2004; Hua 2006: 98; Komzáková 2006.

Egle korpokkur Suwa, 1974: 91 , figs. 242–245; Suh & Kwon, 1985: 188, fig. 13 (1–6); Dely-Draskovits 1993: 52; Xue et al. 1998: 660, fig. 1474; Suwa 1999: 221; Hua 2006: 98. Synonymized by Michelsen (2004).

Egle podulparia Suh & Kwon, 1985: 187 , fig. 12 (1–6). First synonymized with Egle korpokkur Suwa by Griffiths (2003: 2356).

Egle gracilior Zheng & Fan, 1990: 181 , 185, fig. 1 [as fig. 2 in legend]. Synonymized by Griffiths (2003: 2350).

For further references, see Griffiths (2003).

Taxonomic notes. As presently delimited, Egle minuta appears somewhat variable in respect to body size, intensity of grey dusting on body and prementum, and projection of lower facial margin. Nevertheless, I doubt that any splitting into further species is required, at least within Europe. The synonymization by Michelsen (2004) of Egle korpokkur Suwa described from Japan was based on examination of a male paratype in ZMUC. It agrees with typical E. minuta in having lateral parts of epandrium normally setated, broad-based surstyli and pregonites not wider than long; the apical extension of the cerci is unusually broad but credibly within the variational limits of E. minuta .

Description. Very small: wing length 2.5–3.6 mm.

Male. Parafacial in middle narrower than postpedicel. Lower facial margin extended slightly or moderately beyond fronto-parafacial angle. Genal setae in two irregular rows. Prealar seta distinctly shorter than posterior notopleural seta. Proepisternals 1; proepimerals 3–5. Lower calypter shorter than upper calypter but still convex at hind margin. Submedian tibial setae: fore tibia with long and fine 0–1 ad- and 0–2 pv-setae; mid tibia with 0 ad-, 1 pd- and 0–1 short p-setae; hind tibia with 2-4 short av-setae and usually some short pvsetae on middle third. Hind femur with a row of pv-setae on basal two-thirds, all shorter than greatest depth of femur. Tergite VI short, but separate from syntergosternite VII+VIII. Terminalia ( Figs. 152–157 ): Sternite V with setulae along hind marginal incision relatively short, interrupted latero-basally; basal plate with 2–4 short setulae at postero-lateral corners. Epandrium normal-sized, with setulae on lateral parts. Surstyli broad-based alongside margins of cerci; in lateral view relatively slender. Variable in respect to width of cercal extension, but frequently rather slender and always more or less constricted basally. Pregonite barely wider than long; postgonite with anterior transverse ridge. Phallus with epiphallus quite long and apically inflated.

Female. Prementum on lateral parts polished black or at least with a strong black shine through sparse dusting. Lower facial margin extended slightly or moderately beyond fronto-parafacial angle. Genal setae in a single row. Prealar seta slightly shorter than posterior notopleural seta. Proepisternals 1; proepimerals 2–3. Setulae on lower part of katepisternum strikingly fine and dense, forming a “pollen brush”. Lower calypter lobe-like, about half as long as upper calypter. Submedian tibial setae: fore tibia with 0 pd- and 0 p-setae; mid tibia with 1 ad-, 1 pd- and 0–1 p-setae; hind tibia with 2–3 short av-setae. Hind femur on basal half without distinct pv-setae. Oviscapt ( Fig. 197 ): Sternite VII slender, more or less extensively membranized on middle part; epiproct small, often divided along mid-line, with a pair of setulae; hypoproct well retained on distal part, with 2 pairs of setulae. Spermathecae two normal-sized and finely cross-wrinkled, third one markedly reduced in size.

Material examined. European specimens seem from ICELAND, BRITISH ISLES, CZECH REPUBLIC, DENMARK, FINLAND, NORWAY, SLOVAKIA, SPAIN and SWEDEN. UZBEKISTAN [ ZMUC]: Chimgan, alpine meadow, 1800m, 2 females 18.v.1989 (M. Barták); Samarqand, Zeravshan reserve , deciduous wood, 1 female 21–22.v.1989 (M. Barták). JAPAN [ ZMUC]: Hokkaidô : Nopporo, 1 male (paratype: Egle korpokkur Suwa ) 13.iv.1973 (M. Suwa). Also seen from CANADA: Manitoba, New Brunswick, Northwest Territories, Quebec ; USA: Alaska, New York .

Biology. A common early-season species (March to May) in the lowlands of northern Europe. In Denmark I have taken it on flowering Goat willow ( Salix caprea L.) and Grey willow ( S. cinerea L.), in south Sweden on Eared willow ( Salix aurita L.) and Creeping willow ( S. repens L.).

Distribution. A wide-ranging Holarctic species. European distribution as summarized by Michelsen (2004):? Austria, British Isles, Czech Republic, Denmark, Finland, Germany, Iceland, Norway, Poland, Russia, Slovakia, Spain, Sweden and Switzerland. Presently recorded for the first time from Uzbekistan. Eastern Palaearctic distribution includes China: Liaoning, Shanxi, Gansu, Sichuan ( Hua 2006), Japan ( Suwa 1999) and Korea (Suh & Kwon 1985). Reaching the Oriental Region in northern Myanmar ( Ackland & Pont 1977). In North America ranging from low arctic Canada to southern California ( Griffiths 2003).

Relationships. Egle minuta belongs to the E. minuta species group within the E. minuta section (see above).

Figures

FIGURES 152–157. Egle minuta, male terminalia. 152, 153. Sternite V, ventral and lateral views. 154, 155. Hypopygium, caudal and lateral views. 156. Pre- and postgonites, lateral view. 157. Phallus, lateral view. Same scale.

FIGURES 197–199. Egle spp., female terminalia. 197. E. minuta, oviscapt, flat mounted. 198. E. lyneborgi, oviscapt, flat mounted. 199. E. suwai, distal oviscapt, flat mounted [paratype: Denmark]. Same scale.