Of the three Dineura species found in Britain and Ireland, Dineura stilata and Dineura testaceipes can be difficult to tell apart. Dineura testaceipes prefers cooler climes and has a more northerly distribution than Dineura stilata, which prefers warmer conditions.
The head is black with pale on the clypeus and labrum and more or less on the supraclypeal area. The stigma is pale sometimes with some degree of darkening at the margins. The thorax is black above sometimes with varying degrees of pale on the corners of the pronotum, tegulae, edges to the lateral lobes and the front of scutellum. The abdomen is variable. In the darkest specimen almost completely black and in the palest, pale on the sternites, the lateral faces of tergites and tergites eight to ten above.
Dineura testaceipes larvae feed on mountain ash. Other food plants recorded from the continent include rowans, hawthorn and Cotoneaster melanocarpus.
Size: Female: 5 - 6.5mm, male: 4 - 5.5mm
Distribution: England, Scotland, Wales, Ireland
Flight period: May to August
Plant associations: Sorbus aucuparia (mountain ash)
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., Prous, M. and Vardal, H., 2019. The West Palaearctic Dineura species, focussing on Sweden (Hymenoptera, Tenthredinidae). Zootaxa, 4612(4), pp.501-517.