Neurotoma mandibularis - Twin Spinner
One of two species of Neurotoma in Britain, neither of which occurs in Ireland. This species has only been recorded on five occasions, at a variety of locations across southern England between 1907 and 1947 but not since. There would seem no obvious reason why an oak-feeding species noted from several widely-spaced locations in southern Britain should have disappeared, but the lack of records for over 70 years is striking (Musgrove, 2022).
This species broadly speaking black with a metallic blue shine and is less yellow marked with yellow confined to the mandibles and the outer face of the hind tibia. The wings are uniformly hyaline and lack the smokey band of the other species Neurotoma saltuum. The temples are not carinate behind.
Neurotoma mandibularis larvae feed in pairs inbetween two oak leaves which are spun together to form a tent.
Size: 7 - 10mm
GB IUCN Status: Regionally Extinct
GB Rarity Status: Extinct
Flight period: May to June
Plant associations: Quercus robur (English or pendunculate oak).
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. 2022. A review of the status of sawflies of Great Britain - Phase 1: families other than Tenthredinidae. Natural England, unpublished
Viitasaari, M. ed., 2002. Sawflies (Hymenoptera, Symphyta), I: a review of the suborder, the Western Palaearctic taxa of Xyeloidea and Pamphilioidea. Tremex Press.