Dineura virididorsata ( Retzius, 1783 )

Liston, Andrew, Prous, Marko & Vårdal, Hege, 2019, The West Palaearctic Dineura species, focussing on Sweden (Hymenoptera, Tenthredinidae), Zootaxa 4612 (4), pp. 501-517 : 510-512

Dineura virididorsata ( Retzius, 1783)

Tenthredo viridi-dorsata Retzius, 1783: 73 , by indication on Degeer (1771: p. 1002–1004 & plate 38 figs 8–10). Syntypes, larvae and adults (sex not stated), type locality presumably near Degeer’s residence in Lövstabruk ( Sweden, Uppland Province). Type material lost.

Tenthredo nigricans Christ, 1791: 446–447 , by indication on Degeer (1771: p. 1002–1004 & plate 38 figs 8–10). Syntypes, larvae and adults (sex not stated), type locality presumably near Degeer’s residence in Lövstabruk ( Sweden, Uppland Province). Type material lost.

Tenthredo (Allantus) geeri Klug, 1817: 213–214 , by indication on Degeer (1771: p. 1002–1004 & plate 38 figs 8–10). Syntypes, larvae and adults (sex not stated), type locality presumably near Degeer’s residence in Lövstabruk ( Sweden, Uppland Province).Type material lost.

Nematus degeeri: Thomson (1871) , misspelling of geeri Klug.

Nematus varius Serville, 1823: 71–72 . Syntypes ♂, Paris, types lost ( Lacourt 2000). Types are the same specimens as for N. varius Lepeletier.

Nematus varius Lepeletier, 1823: 69 . Syntypes ♂, Paris, types lost ( Lacourt 2000). Listed as synonym of virididorsata by Dalla Torre (1894). Types are the same specimens as for N. varius Serville.

Nematus hartigii Gimmerthal, 1844: 37–38 . Holotype ♀, in der Nähe von Riga [ Latvia, near Riga], specimen probably lost. Listed as synonym of virididorsata by Dalla Torre (1894).

Dineura virididorsata var. dorsalis Enslin, 1915: 319 . Syntypes ♀ ♂, type locality not stated; lectotype ♀ here designated, in ZSM (GBIF-GISHym3089, images: https://doi.org/10.6084/m9.figshare.7851458). Type locality: Finland, Karislojo. Paralectotype: 1♂ (GBIF-GISHym3088), in ZSM.

Dineura pullior Schmidt & Walter, 1995: 387–392 . Holotype ♀ (GBIF-GISHym3697, images: https://doi.org/10.6084/ m9.figshare.7856741), in ZSM. Type locality: Finland, Kevo , Utsjoki. New synonym.

Taxonomy. According to Schmidt & Walter (1995), Dineura pullior occurs in Europe only north of 68°N, together with virididorsata , although pullior is by far the more common. We found that none of the morphological characters which was stated by Schmidt & Walter (1995) to distinguish pullior from virididorsata is stable. Although there is clearly a tendency towards a darker colour pattern and smaller body size in high northern areas (the form named pullior ), the differences described in the lancets of the two nominal species (Figs 23–24) are not completely correlated with colour pattern, and individuals with intermediate types of lancet setation and tangium shape were found (additional images: https://doi.org/10.6084/m9.figshare.7873466). Perhaps the extreme variability in the size and number of setae is correlated with body size: smaller females having fewer setae. The shape of the tangium is also apparently variable, but can be difficult to interpret because of distortion during preparation. Schmidt & Walter (1995) stated “In the male of D. pullior the dorsal edge of the valvispina, viewed laterally, tapers evenly to an acute apex (Fig. 9), whereas that of D. virididorsata is sharply angled (Fig. 10)”. The difference, even as illustrated in their paper, is extremely slight. We detected no significant differences in penis valves of specimens tentatively determined ac-

Additional description. Body length: ♀ 4.9–8.0mm, ♂ 4.9–7.0. Head from completely pale except for directly around ocelli and along upper postoccipital grooves (Figs 3–4), to extensively dark, with contiguous black marking covering postocellar and ocellar areas, reaching forward to toruli (Figs 5–6), and occiput mostly dark (Fig. 10). Mesonotum from completely pale (Fig. 9) to completely dark (Fig. 10). Underside of thorax often entirely pale, but more or less black can be anepimeron, upper edge of mesepisternum, and mesepisternum ventrally. Abdomen from completely pale except for tergum 1 medially and narrow anterior edge of tergum 2 (Fig. 9), to extensively black on terga except for downturned lateral margins and more or less terga 8, 9, and 10 (Fig. 10). Antenna and legs entirely pale (except for more or less obscurely darkened tarsi and apices of tibiae). Female (Figs 8–10): lancet (Figs 23–24). Male (Fig. 11): penis valve ( Figs 28–29 ).

Total number of specimens examined: about 270.

Similar species. Dineura virididorsata is easily distinguished from the other West Palaearctic species by its extensively pale orbits. Dineura betulivora Togashi, 1995 ( Japan) is according to the original description very similar to the dark specimens of virididorsata formerly called pullior , and possibly not distinct, but we have not examined type specimens.

Life history. Host plants: Betula pendula and B. pubescens (including the varieties or subspecies carpatica and czerepanovii) ( Pschorn-Walcher & Altenhofer 2000, Macek 2015), and rarely on B. nana (personal communication from V. Vikberg). A number of studies (several of which are cited by Schmidt & Walter 1995) deal with various aspects of the ecology and biology of virididorsata species in northern Fennoscandia. Some defoliation events have been recorded at high latitudes on mountain birch, e.g. by Koponen (1981) in northernmost Norway.

Distribution. Through most of northern and central Europe, including Britain and Ireland ( Taeger et al. 2006), south to the Iberian Peninsula ( Liston 2016), and Transpalaearctic ( Zhelochovtsev & Zinovjev 1995) through Russia ( Zhelochovtsev & Zinovjev 1995) to Hokkaido, Japan ( Togashi 1990) and Hubei Province, China ( Wei & Nie 1998). Occurrence in Sweden: published records; distributed throughout the whole of Scandinavia ( Thomson 1871, as Nematus degeeri ). Material examined: Skåne, Halland, Småland, Öland, Gotland, Östergötland, Västergötland, Bohuslän, Södermanland, Uppland, Västmanland, Dalarna, Gästrikland, Härjedalen, Jämtland, Ångermanland, Hälsingland, Norrbotten, Lycksele Lappmark, Lule Lappmark, Torne Lappmark.

Specimens examined. Estonia: 1♀ (DEI-GISHym31798), Jõgevamaa, Mustvee 1.8km S, 40m, 04.06.2015, leg. Liston, Prous & Taeger ( SDEI) .

Finland: 11♀, 6♂ ( SDEI, ZSM) . Specimens formerly determined as pullior : 1♂ (DEI-GISHym11573), Nuor- gam 17km SSE, 69.94°N 28.04°E, 20.06.2001, leg. A. Taeger & C. Kutzscher ( SDEI) . 1♀ (DEI-GISHym19239), Kevo , 69.74°N 26.99°E, Malaise trap, 15– 20.06.2001, leg. Taeger, Kraus & Kutzscher ( SDEI) . 1♂ (DEI-GIS- Hym 19619), Kilpisjärvi, Fjelde Pikku-Malla, 69.05°N 20.80°E, 24.06.2004, leg. M. Viiitasaari ( SDEI) . 1♀ (DEI- GISHym31792), Utsjoki , Isieskujoki 774:50, 09.06.1992, leg. M. Viiitasaari ( SDEI) . 1♀, 1♂ (DEI-GISHym31801, 31802), Utsjoki , 69.88°N 27.00°E, 1990, reared ( SDEI) .

Germany: 17♀, 3♂ ( SDEI, ZSM) .

Portugal: 2♀, see Liston (2016) ( SDEI) .

Russia: Kemerovo Region 2♀, 5♂ (Institute of Systematics and Ecology of Animals , Siberian Branch RAS, Novosibirsk) . 2♀ (DEI-GISHym31810 and 31811; formerly determined as pullior ), Primorskiy Kray, Sichote Alin , meteorological station 28km SE Chugeyevka, 43.59°N 134.08°E, 01.06.1993, leg. A. Taeger ( SDEI) .

Scotland: 1♀ ( SDEI) .

Sweden: 132♀, 48♂ ( MZLU, NHRS, SDEI) , including the following [other provinces: see under species treatment]. Torne Lappmark: 1♀ (DEI-GISHym15244), Abisko , Mt. Njulla, 400-700m, 29.06.2012, leg. Liston & Taeger ( SDEI) . 2♀ (DEI-GISHym31794, 31795), Abisko National Park , E 10, 390m, 30.06.2012, leg. Liston & Taeger ( SDEI) . 1♀ (DEI-GISHym31809), Abisko , Mt. Njulla, 600-900m, 23.06.2016, leg. Liston ( SDEI) . 1♂ (DEI- GISHym80155), Abisko 6km W, 650-900m, 02.07.2016, leg. Liston & Prous ( SDEI) . 1♂ (DEI-GISHym19664; previously determined as pullior ), Stordalen , 68.35°N 19.04°E, 17.06.2012, leg. A. Liston, A. Taeger & S. M. Blank ( SDEI) .

Figures

FIGURES 28–35. Dineura, penis valves. 28 virididorsata ♂, penis valve (80155). 29 virididorsata ♂, penis valve (19664; formerly det. pullior). 30–31 stilata ♂, penis valve (11350). 32–33 Dineura testaceipes ♂, penis valve (31800). 34 Dineura parcivalvis ♂, Russian Far East, penis valve (80232). 35 Dineura parcivalvis ♂, Finland, penis valve [“allotyp” FMNH].