One of the Tenthredo atra group (atra, ignobilis, moniliata) that may require further revision. Tenthredo ignobilis was identified as present in Scotland by Liston et al following collecton of samples in 2010. This species was previously considered as a colour morph of atra. The Scottish specimens differ slightly from European examples. Tenthredo ignobilis has a black stigma and apex of costa (brown in moniliata). In the female the tegulae are black (red in moniliata) and the mesepisterum in males is ventrally completely black (also black in atra, but largely red in moniliata). In females the abdomen is marked red on tergites three to five and occasionally the extreme margins of two and six (female abdomen entirely black in atra).
Tenthredo ignobilis larvae feed on stonecrops.
Size: 11 - 12mm
Flight period: May to August
Plant associations: Sedum telephium and Sedum rosae
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
Fekete, K. (2018) Beginner’s guide to identifying British Tenthredo, Natural History Museum, London. http://www.nhm.ac.uk/content/dam/nhmwww/take-part/identification-trainers/sawflies-guide-id-trainees.pdf [Accessed 26Apr2019]
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.