EUURA ISCHNOCERA GROUP

Euura ischnocera - Slenderhorn Leaf-galler

Nematus ischnocerus Thomson, 1863
Phyllocolpa ischnocera (Thomson, 1863)
Nematus leucostigmus Cameron, 1876
Nematus prussicus Zaddach, 1883
Nematus commixtus Zaddach, 1884

Apart from a single 19th century specimen from Scotland, the only records are from targeted recording expeditions in the Highlands between 1992 and 2010. Liston et al. (2012) concluded that 'Pontania ischnocera is evidently a widespread and rather abundant species in the southern Highlands.' (Musgrove, 2024).

The stigma is usually entirely pale, but can be apically darkened. See Liston et al (2017) for determination.

Larvae feed on dark-leaved willow which is an upland species. The larvae cause a leaf fold, either spirally twisted or a marginal fold.

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Size: Female: 3.4 - 3.9mm, male: 3.2 - 4.2mm

GB IUCN status: Vulnerable
GB rarity status: Nationally Scarce

Distribution: Scotland

Flight period: Uni- or bivoltine

Plant associations: Salix myrsinifolia (dark-leaved willow)

The National Biodiversity Network records are shown on the map below. (See terms and conditions)

References:

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

Musgrove, A.J. 2024. A review of the status of sawflies of Great Britain - Phase 3: The Tenthredinidae (subfamily Nematinae). Natural England, unpublished