First recognised as a separate British species by Liston & Blank (2006) from leaf-mines at Dover Castle, with no further records until 2013. Since then, recorded sparsely across England and Wales north to Liverpool, and would seem to be less frequent than Heterarthrus fiora but likely very overlooked (Musgrove, 2023).
One of three Heterarthrus species feeding on Acer species; fiora (formerly misidentified as aceris), cuneifrons and wuestneii. There is historically, confusion between the three and historic records must be treated with uncertainty. This species cannot reliably be distinguished from Heterarthrus wuestneii from the insect morphology. In ecological terms, cuneifrons oviposits into the interior of the leaf blade, whereas wuestneii lays in the leaf margin. Also, cuneifrons feeds on sycamore in Britain, whereas wuestneii feeds on field maple.
Larvae mine the leaves of sycamore starting from the interior of the leaf blade, whereas fiora starts at the leaf margin. A circular cocoon is made from the upper leaf epidermis. This cocoon separates from the leaf prior to the autumn leaf drop leaving a neat hole visible in the leaf. The cocoon works its way into the litter layer.
Size: 3.5 - 4.5mm
GB IUCN Status: Data Deficient
GB Rarity Status: None
Distribution: England, Wales
Flight period: Univoltine, May to June
Plant associations: Acer pseudoplatanus (sycamore)
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., Mutanen, M. and Viitasaari, M., 2019. On the taxonomy of Heterarthrus (Hymenoptera, Tenthredinidae), with a review of the West Palaearctic species. Journal of Hymenoptera Research, 72, p.83.
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 Natural England, unpublished