Mesoneura opaca - Opaque Oak Nematine

North to northern Scotland, seemingly common and widespread (Musgrove, 2024).

A rather drab but nevertheless distinctive species. This species has an overall black and tan colour scheme. In the darkest forms the thorax is all black as is the abdomen but the legs, wings, stigma and sides of the abdomen are a rather weak orangy brown to off-white. Very variable such that the thorax may be almost entirely orange-brown. Tegulae and pronotum are usually orange-brown in all forms. This is a parthenogenic species with males unknown.

Mesoneura opaca larvae feed on oaks.

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Size: 6 - 7mm

GB IUCN status: Least Concern
GB rarity status: None

Distribution: England, Scotland, Wales, Ireland

Flight period: April to June

Plant associations: Quercus spp. (oaks)

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

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 Natural England, unpublished