NON-GROUPED

Euura imperfecta - Flawed Larch Nematine

Nematus imperfectus Zaddach, 1876
Larinematus imperfectus (Zaddach, 1876)

Distributed north to central Scotland, but few records, as with most conifer-feeding sawflies. Still being reported but likely very overlooked. Was the fifth most frequent nematine noted in yellow bowl traps in Welsh spruce (and presumably larch) forests by Enston & Williams (2023) (Musgrove, 2024).

The head is brownish-yellow above, with the mouthparts yellow. Marked with black are the antennae and the ocellar area. The thorax is also black but marked with yellow on the posterior corners of the pronotum, the tegulae, more or less the side and back margins of the prescutum and mesoscutum, the scutellum, the mesepisternum, rarely the mesosternum and more or less the metepisternum. The abdomen is black on top with the ninth tergite and underside of the abdomen more or less yellowish.

Euura imperfecta larvae feed on larches. Ova are deposited on the face of short-shoot needles and the larvae feed on the short shoots and later on longer emergent shoots. They are approx. 15 mm. long when mature. The main feeding period is in May-June (July in higher altitudes).

Size: 5.0 - 7.0mm.

GB IUCN status: Least Concern
GB rarity status: None

Distribution: England, Scotland, Wales

Flight period: Univoltine, April to May (June in higher altitudes)

Plant associations: Larix decidua (European larch)

The National Biodiversity Network records are shown on the map below. (See terms and conditions)

References:

Benson, R.B., 1952. Handbooks for the Identification of British Insects. Hymenoptera, Symphyta, Vol 6, Section 2(a-c), Royal Entomological Society, London

Liston A, Knight G, Sheppard D, Broad G, Livermore L (2014) Checklist of British and Irish Hymenoptera - Sawflies, ‘Symphyta’. Biodiversity Data Journal 2: e1168. https://doi.org/10.3897/BDJ.2.e1168

Liston, A.D., Knight, G., Heibo, E., Bland, K.P., Barstad, T.E., Blank, S.M., Boevé, J.L., Fiedler, C., Grearson, K.J., Halstead, A. and Jacobs, H.J., 2012. On Scottish sawflies, with results of the 14th International Sawfly Workshop, in the southern Highlands, 2010 (Hymenoptera, Symphyta). Beiträge zur Entomologie= Contributions to Entomology, 62(1), pp.1-68.

Muche, W.H., 1974. Die Nematinengattungen Pristiphora Latreille, Pachynematus Konow und Nematus Panzer (Hym., Temthredinidae). Deutsche Entomologische Zeitschrift, 21(1/3), pp.1-137.

Musgrove, A.J. 2024. A review of the status of sawflies of Great Britain - Phase 3: The Tenthredinidae (subfamily Nematinae). Natural England, unpublished

Prous, M., Liston, A., Kramp, K., Savina, H., Vårdal, H. and Taeger, A., 2019. The West Palaearctic genera of Nematinae (Hymenoptera, Tenthredinidae). ZooKeys, 875, p.63-127