Heterarthrus nemoratus

Recorded widely across all of mainland Britain, although with no records from south-west England to date (Musgrove, 2023).

Males of this species are unknown. On the thorax the lateral mesoscutal lobes are black and the mesepisternum mostly so. The abdomen is black with at most white flecks posteriorly on the tergites. The fore wing is yellowish basally, clear apically and infuscate behind the stigma. The antennae have 10 to 11 segments. The hind femora, tibiae and tarsi are mainly white, although the bases of the femora and the coxae are black.

Eggs are deposited in the leaf edge. The larvae create a blister mine with a characteristic reddish tinge and pupate inside the leaf.

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Size: 4 - 6mm

GB IUCN Status: Least Concern
GB Rarity Status: None

Distribution: England, Scotland, Wales, Ireland

Flight period: Univoltine, May to July

Plant associations: Betula spp. (birches)


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 Natural England, unpublished