Recorded locally across much of Britain, although absent to date from northern Scotland, south Wales and south-west England (Musgrove, 2023).
As with all Tenthredopsis species Tenthredopsis ornata is variable in colour. The description given here follows Blank and Ritzau 1998 but it should be noted that British specimens may differ in colour from continental counterparts.
Tenthredopsis ornata is the only British and Irish Tenthredopsis species with a deeply incised clypeus and it is the smallest of the British species. Both genders are similar. The hind tarsi are mostly black though the apical segments are often brownish. The abdomen is black with dark red lateral marks on the middle segments. The mesepisternum is entirely black. The underside of the abdomen is marked with black longitudinal stripes.
Larvae feed on grasses including False-brome and are often found near water courses or damp meadows.
Size: 8 - 10mm
GB IUCN Status: Least Concern
GB Rarity Status: None
Distribution: England, Scotland, Wales
Flight period: May to June
Plant associations: Gramineae (grasses) including Brachypodium sylvaticum (False-brome)
Benson, R.B., 1952. Handbooks for the Identification of British Insects. Hymenoptera, Symphyta, Vol 6, Section 2(a-c), Royal Entomological Society, London
Blank, S.M. and Ritzau, C., 1998. Die Tenthredopsini Deutschlands (Hymenoptera: Tenthredinidae). Pflanzenwespen Deutschlands (Hymenoptera, Symphyta). Kommentierte Bestandsaufnahme, pp.227-246.
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. 2023. A review of the status of sawflies of Great Britain - Phase 2: The Athaliidae and the Tenthredinidae (excluding Nematinae). Natural England, unpublished