Stauronematus platycerus (Hartig, 1840)

Prous, Marko, Liston, Andrew, Kramp, Katja, Savina, Henri, Vardal, Hege & Taeger, Andreas, 2019, The West Palaearctic genera of Nematinae (Hymenoptera, Tenthredinidae), ZooKeys 875, pp. 63-127 : 63

Stauronematus platycerus (Hartig, 1840)

Nematus platycerus Hartig, 1840: 27. Lectotype ♂, designated by Liston (2007:139), in ZSM (GBIF-GISHym3385, images: https://doi.org/10.6084/m9.figshare.4791952). Type locality: Norddeutschland (Germany).

Nematus vallator Snellen van Vollenhoven, 1858: 191-194, pl. 12. Lectotype ♀, examined, designated by Thomas (1987: 72), in RMNH. Type locality: Leiden (Netherlands). Synonymy with Nematus compressicornis auct. by Cameron (1878: 267).

Nematus cebrionicornis Costa, 1859: 20. Syntype(s) ♂, not examined, most likely in MZFN. Type locality: Camaldoli Hills, near Naples (Italy). Synonymy with Nematus compressicornis auct. by Brischke (1884: 123) (see also Liston 2007: 139).

Nematus callicerus Thomson, 1863: 619-620. Lectotype ♀, designated by Liston (2007:139), in MZLU. Type locality: Ringsjön (Sweden). Synonymy with Nematus compressicornis auct. by Cameron (1885: 55).

Description.

Body length: female 4.5-7.5 mm, male 4.5-6.0 mm. Head black, except for mandibles and palpi. Pronotum completely black, or only extreme upper and rear edges brown. Mesepisternum more densely pubescent above than below but usually without entirely glabrous area on lower half. Hind coxa with at least basal half black. Trochanters and femora completely pale (yellowish). Tibia more whitish: pro- and mesotibia and pro- and mesobasitarsus entirely pale, with rest of tarsus darkened. Metatibia with approx. apical third black but spurs pale. Metatarsus black. Wing membrane hyaline; venation largely pale except for dark fore wing stigma . Abdomen entirely black. Female: head in dorsal view subparallel behind eyes. Antennae normal; not laterally compressed. Cerci pale to dark. Lancet: Fig. 136 . Male: head in dorsal view behind eyes only slightly contracted. Antennae strongly laterally compressed, flagellomeres ventrally somewhat produced; may be reddish. Penis valve: Fig. 138 .

Similar species.

When the shape of the claw is overlooked, Stauronematus adults are frequently misidentified as Pristiphora . The long, thin cerci of female Stauronematus , and the shape of the valvula 3 in dorsal view, are however quite different to any West Palaearctic Pristiphora species.

Life history.

Host plants: mainly Populus spp., especially tremula, but also nigra, balsamifera, deltoides, alba, and many cultivated forms ( Pschorn-Walcher and Altenhofer 2000, Brischke 1884, Cavalcaselle 1968); less often on Salix purpurea ( Pschorn-Walcher and Altenhofer 2000, our own observations). Frequently recorded as bivoltine, but possibly has even three generations in warmer areas. Sex ratio appears to be normal for netted specimens, i.e., males about as abundant as females, but is heavily skewed towards males in material collected with Malaise traps. Oviposition in a double row in the leaf petiole. The larvae eat holes in the leaf blade and surround the feeding site with “palisades” ( Fig. 85 ) made of a dried secretion produced in their mandibular glands.

Distribution.

Found through much of continental Europe, from the Iberian Peninsula and Balkans, to Finland and Norway, and also the British mainland ( Taeger et al. 2006). According to Sundukov (2017) also occurs in Caucasus, Turkey, Iran, Kyrgyzstan, Kazakhstan, China, Korean Peninsula, and Japan.

Occurrence in Sweden.

Published records: Skåne ( Thomson 1871), Småland, Uppland, Norrbotten Lule Lappmark ( Haris 2009). Material examined from Skåne Uppland.

Specimens examined.

France: 2♀ (RMNH). Germany: 23♀ (including DEI-GISHym11317 and 19761), 24♂ (including DEI-GISHym19762) (SDEI, ZSM). Netherlands: 4♀, 6♂ (RMNH). Portugal: Aveiro: 1♀, Castelo de Paiva 7 km SSW, 260 m, 41.00033N, 8.27777W, 14.05.2012, leg. Blank, Jacobs, Liston & Taeger (SDEI). Spain: 1♀, 1♂ (SDEI). Sweden: Skåne: 1♂, Malmö, Limhamns Kalkbrott, 55.56760N, 12.93283E, 9.06-25.10.2007, leg. B. W. Svensson & Co. (MZLU). 1♂, Malmö, Limhamns Kalkbrott, 55.56760N, 12.93283E, 27.07.-16.08.2009, leg. B. W. Svensson & Co. (MZLU). Uppland: 1♂, Haninge kommun, Tyresta, Urskogsslingan, hällmark, 59.17685N, 18.24690E, 04-26.08.2004, leg. SMTP (NHRS). 1♂, Huddinge kommun, Sofielunds återvinningsanläggning, avlastningsstation, 59.17656N, 17.99379E, 18.05.-07.06.2004, leg. SMTP (NHRS). 1♂, Älvkarleby kommun, Marma skjutfält, east of Sköldvägen/Kanonvägen, 60.52431N, 17.45151E, 17.06-02.07.2003, leg. SMTP (NHRS). 1♀, 1♂, Älvkarleby kommun, Båtfors, between Milsten and Båtforstorpet, 60.46077N, 17.31782E, 17.06.-03.07.2003, leg. SMTP (NHRS). 1♂, same locality as previous, 14.06.-04.07.2005, leg. SMTP (NHRS). 4♂, Uppsala kommun, Ekdalens naturreservat, southern hillside, 59.97153N, 18.35495E, 07-21.07.2003, leg. SMTP (NHRS). 1♂, same locality as previous, 04-18.08.2003, leg. SMTP (NHRS). 2♂, same locality as previous, 18.08.-01.09.2003, leg. SMTP (NHRS). 1♂, same locality as previous, 02.-16.06.2004, leg. SMTP (NHRS).

Figures

Figures 134 - 139. Stauronematus 134 platycerus DEI-GISHym 19761 ♀ lateral 135 saliciphilus holotype ♀ DEI-GISHym 11427 lateral 136 platycerus DEI-GISHym 11317 lancet 137 saliciphilus DEI-GISHym 11427 lancet 138 platycerus DEI-GISHym 19762 penis valve 139 saliciphilus DEI-GISHym 11435 penis valve. Scale bar: 1 mm (134).

Figures 77 - 87. Larvae of Nematinae 77 Cladius grandis 78 Euura sp. amentorum group 79 Nematinus acuminatus 80 Nematinus luteus 81 Nematinus steini 82 - 83 Anoplonyx albitarsis 84 Hoplocampa crataegi 85 Stauronematus platycerus 86 Pristiphora malaisei from Potentilla fruticosa 87 Hemichroa crocea.