Euura triandrae - proxima group (formerly Pontania triandrae )
See Liston et al (2017) for determination of adults. Males are rare. There is some doubt as to whether this is in fact a species separate to Euura proxima.
Euura triandrae larvae feed on almond willow causing coffee bean shaped galls that transect the leaf blade but grow more on the upper surface . Single, or very few galls per leaf. The galls are green becoming dark red or brownish above, yellow-green below, and with a smooth surface. There is some doubt as to whether the gall characteristics are useful as an indicator of the species or whether they are caused by the host plant.
Size: Female: 2.9 - 4.5mm, male: not assessed
Distribution: England, Scotland, Ireland
Flight period: Bi- or multivoltine
Plant associations: Salix triandra (almond willow)
The National Biodiversity Network records are shown on the map below. (See terms and conditions)
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.D., Heibo, E., Prous, M., Vårdal, H., Nyman, T. and Vikberg, V., 2017. North European gall-inducing Euura sawflies (Hymenoptera, Tenthredinidae, Nematinae). Zootaxa, 4302(1), pp.1-115.
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