Sterictiphora geminata - Dark Twinhorn

One of two species in this genus widely distributed north to Sutherland (Musgrove, 2022). The abdomen is mostly black with a bronze sheen (in S. angelicae only the first two tergites are black) and thorax surface is dulled by microsculpture and puncturation.

Sterictiphora geminata larvae feed on roses and occasionally Mountain Ash. Other larvae of this genus feed from the edge of the leaf working inwards in a meandering zig-zag pattern similar to the Elm Zig-zag sawfly.

Jump to other Argidae

Size: 5 - 7mm.

IUCN Status: Least Concern
GB Rarity Status: None

Distribution: England, Scotland, Wales, Ireland

Flight period: April to June

Plant associations: Rosa spp., roses (Benson, 1952) and Mountain Ash, Sorbus aucuparia (Liston, 1995).

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

References:

Benes, K. 1968: Description of the Larvae of Sterictiphora geminata and Cladardis elongatula (Hymenoptera, Symphyta). - Acta entomologica bohemoslovaca, Praha 65(3): 222-225

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., 1995. Compendium of European Sawflies, Chalastos Forestry, Daibersdorf

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

Lorenz, H. and Kraus M., 1957. Die Larvalsystematik der Blattwespen (Tenthredinoidea und Megalodontoidea). - Abhandlungen zur Larvalsystematik der Insekten No. 1. Berlin: Akadamie - Verlag

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 Natural England, unpublished