Cimbex connatus - Alder Clubhorn
The species seems to have been largely absent throughout much of the 20th century, but from 1997 onwards the species had been found west to Cornwall, South Wales and Lancashire, and north to Tees-side (Musgrove, 2022).
A large yellow and brown species very similar to Cimbex luteus. However, Cimbex connatus is a darker insect with dark marking on the first three tergites. In luteus the 3rd tergite has at most a narrow central dark mark and with much more extensive yellow on the underside of the abdomen. In connatus, the thorax is generally a darker orange colour and the back of the head and scutellum are shinier with less puncturation and fewer hairs.
Larvae feed on alders.
Size: 20 - 28mm
GB IUCN Status: Least Concern
GB Rarity Status: None
Distribution: England, Wales, Ireland
Flight period: May to June
Plant associations: Alnus glutinosa (Alder), Alnus incana (Grey Alder).
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
Musgrove, A.J. 2022. A review of the status of sawflies of Great Britain - Phase 1: families other than Tenthredinidae. Natural England, unpublished