Euura vesicator (Bremi-Wolf, 1849)

Liston, Andrew D., Heibo, Erik, Prous, Marko, Vårdal, Hege, Nyman, Tommi & Vikberg, Veli, 2017, North European gall-inducing Euura sawflies (Hymenoptera, Tenthredinidae, Nematinae), Zootaxa 4302 (1), pp. 1-115 : 100

vesicator subgroup

Euura pustulator ( Forsius, 1923) comb. nov.

Pontania pustulator Forsius, 1923: 51 –54. Described: ♀, ♂, larva, gall, recorded host: Salix phylicifolia . Lectotype, ♀, designated by Vikberg & Zinovjev (2006), RFT [examined]. Type locality: Finland, Sompio Lapland, Sodankylä, Torpan Paavo.

Pontania (Eupontania) pustulator: Zinovjev (1985) .

Pontania (Pontania) pustulator: Viitasaari & Vikberg (1985) .

Nematus (Pontania) pustulator: Zhelochovtsev (1988) .

Eupontania pustulator: Vikberg & Zinovjev (2006) .

Variability. Female: Body length: 3.0– 6.1mm. Head except for labrum, and more or less clypeus completely black, to extensively pale with black only on postocellar area, occiput, and as patch around ocelli. Dorsum of thorax completely black, except for pronotum and tegulae, to whole mesoscutellum and lateral parts of mesoscutal lobes pale. Mesepisternum ventrally pale to completely black. Terga 3–10 to 6–10 completely pale. Male: 4.0– 6.6mm. Dorsal posterior angle of pronotum pale to black. Sternum 9 pale to black. Total number of specimens examined: 17.

Genetic data. The nearest neighbouring barcode of a European taxon is that of E. vesicator , with approx. 3.8% difference.

Similar species. In Europe, only E. vesicator is similar. As stated by Vikberg & Zinovjev (2006), the head of female E. pustulator is usually pale marked on lower gena, lower lateral face and supraclypeal area (these parts completely black in E. vesicator ), but this is not an absolutely reliable way of separating them: these parts are nearly entirely black in two female E. pustulator from Härjedalen.

Bionomics. Host plants: Salix phylicifolia ( Forsius 1923, Vikberg & Zinovjev 2006), S. pulchra [in Polar Urals] (Vikberg & Zinovjev 2006). The mention by Benson (1958) of S. nigricans (= myrsinifolia ) as a host was thought by Zinovjev (1999) to be mistaken, although Harrison (1937) recorded S. andersoniana (currently usually treated as a synonym of myrsinifolia ) and S. phylicifolia × andersoniana as more rarely used hosts, after S. phylicifolia . According to our own observations, galls are seldom to be found on plants of S. phylicifolia showing evidence of hybridisation with S. myrsinifolia . Such hybrids are in many European regions more abundant than pure S. phylicifolia , and this may explain why E. pustulator is scarce or local in some areas. Biology: Forsius (1923), Price et al. (1999), Roininen et al. (2002). A strictly univoltine species.

Distribution. Northern parts of British Isles, Scandinavia, N. Russia and Slovak Republic (Carpathians), east to Polar Urals (Vikberg & Zinovjev 2006, Roller 1999). Published statements that E. pustulator occurs in China (e.g. Xiaodong & Zi 2010) seem likely to be based on misidentifications. Occurrence in Sweden: published records; Dalarna (Haris 2009), Härjedalen ( Coulianos & Holmåsen 1991), Jämtland ( Benander 1969). Material examined: Dalarna, Härjedalen, Lycksele Lappmark, Lule Lappmark.