Homoporus nypsius (Walker, 1839)

Homoporus nypsius (Walker, 1839) View in CoL

Figs 27, 28

Material examined. 4 ♀♀, 3 ♂♂: IRAN, West-Azarbaijan Province , Naqadeh, Solduz Wetland, 37º02′ N, 45º35′ E, 1277 m a.s.l., 21 July 2020, 29 April 2021, M. Razmi leg., ex Calamagrostis epigejos GoogleMaps .

Diagnosis (abstracted from Walker 1839). The primary diagnostic characteristics of females ( Fig. 27B) that differentiate this species include: a prominent fuscous region on the fore wing ( Fig. 28E), a tapered antennal clava ( Fig. 27D), absence of lateral folds on the propodeum ( Fig. 28F), and a blue-black coloration of the head and mesosoma. Although morphologically similar to H. destructor (particularly in antennal structure, propodeum, and general form), at least females are distinguished by their distinctive fore wing infuscation ( Figs 27A,B, 28E,H). Other diagnostic characteristics are: pronotum equal to mesoscutum in width ( Fig. 28D); gaster entirely black with a metallic sheen ( Fig. 28G); typically, fore wing basal cell bare ( Fig. 28E), and setae on head and mesosoma seldom markedly whitish; antennae with Fu 3 not anelliform and generally equal to or longer than Fu 4, which has mps sensilla ( Fig. 27D); marginal vein 1.1‒1.3× as long as stigmal vein and postmarginal vein longer than marginal vein, which is thickened and has a fuscous region beneath it ( Fig. 28E,H); mandibles with three teeth ( Fig. 28B); scutellum coarsely reticulate; head transverse and broader than mesosoma, with a pronounced reticulate-punctate sculpture; mesosoma ( Fig. 28A,D) broad with prominent sculpturing and propodeum without carinae ( Fig. 28F); legs robust; wings fully developed; gaster with a brownish-black hue with basal tergite slightly lighter ( Fig. 28G).

Primary diagnostic features of the male ( Fig. 27A) are: antenna ( Fig. 27C) with two anelli and six funiculars, with the combined length of pedicel and flagellum greater than width of head; flagellum filiform and setose; head and mesosoma with muted color; fore wing with postmarginal vein longer than marginal vein, which is thickened and has a pallid fuscous region beneath it; pronotum as wide as mesoscutum; mandibles with three teeth; gaster oval and shorter than mesosoma; marginal vein of fore wing 1.1‒ 1.3× as long as stigmal vein ( Fig. 27A).

Distribution. IRAN: West Azarbaijan Province ( new record). EXTRALIMITAL: Europe, Kazakhstan, Morocco, New Zealand, North America, Russia, Transcaucasus ( UCD Community 2023).

Biological association. This species acts as a solitary, primary ectoparasitoid of Tetramesa within their galls, with similar development observed on the Hessian fly, Mayetiola destructor (Say, 1817) ( Diptera : Cecidomyiidae ) larva inside their puparia ( UCD Community 2023). While it represents one of the more important parasitoids of Tetramesa , its role as a parasitoid of the Hessian fly appears negligible. The only recorded instance of its development on this particular host seems to be largely incidental. The consistent co-occurrence of stem gall wasps ( Tetramesa spp. ), Gall midges, and this parasitoid species on Calamagrostis host plants in our field surveys provides empirical support for this trophic association. This ecological interaction, particularly the parasitoid’s synchronous emergence with Tetramesa populations, strongly corroborates its host-specific relationship with these gall-makers.