Arge expansa - Pale Birch Fusehorn

One of the black species. Considered by some authors to be a subspecies of Arge fuscipes., there does however seem to be good separation of the characteristics between the two species. Arge expansa is thought to be a cooler climate species and records that appear to refer to expansa come from Scotland, Wales and Ireland, with the only acceptable English records to date being from the Whixall Moss complex on the Welsh border (Musgrove, 2022). Females have a pale costa and subcosta (dark in fuscipes) and in males the hind tibia are white at the base (entirely black in fuscipes).

Larvae feed on birch and willow. 

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Size: 8 - 11mm.

IUCN Status: Least Concern
GB Rarity Status: Nationally Scarce

Distribution: England, Scotland, Wales and Ireland

Flight period: June to July

Plant associations: Betula spp. and Salix spp.. Birches and willows (Muche, 1977).


Benson, R.B., 1952. Handbooks for the Identification of British Insects. Hymenoptera, Symphyta, Vol 6, Section 2(a-c), Royal Entomological Society, London

Lacourt J. Hymenoptera of Europe 2. Sawflies of Europe. NAP Editions; 2020.

Lindqvist, E. 1973: Taxonomische Bemerkungen über einige Blattwespen I (Hymenoptera, Symphyta). - Notulae Entomologicae, Helsingfors 53: 33-39

Liston A, Knight G, Sheppard D, Broad G, Livermore L (2014) Checklist of British and Irish Hymenoptera - Sawflies, ‘Symphyta’. Biodiversity Data Journal 2: e1168.

Muche, W. H. 1977: Die Argidae von Europa, Vorderasien und Nordafrika (mit Ausnahme der Gattung Aprosthema) (Hymenoptera, Symphyta). - Entomologische Abhandlungen. Staatliches Museum für Tierkunde in Dresden , Leipzig 41, Supplement: 23-59.

Musgrove, A.J. 2022. A review of the status of sawflies of Great Britain - Phase 1: families other than Tenthredinidae. Natural England, unpublished