Tremex columba - Trembling Woodwasp
Britain is not part of the natural range of the species, which is widespread across North America. There are a handful of records associated with imported wood, one of which was noted as having been imported from America, and the species is not though to be established in Britain or Ireland. All specimens should be examined to rule out other possible imported Tremex species. A single specimen of the similar T. fuscicornis was recently discovered in a consignment of glass from Italy (Musgrove, 2022).
The antennae of Tremex species are short by comparison to other Sirid wood wasps. There is some variation in colour within this species. Females are varying degrees of brown on the abdomen with yellow across the bases of the tergites giving a striped appearance. The tibia and tarsae are yellowish with darker femora. Males are more uniformly brown to orange-brown with hind legs that are dark but ringed with yellow on the tibiae and femora.
Tremex columba larvae feed inside timber of dead and dying deciduous hardwoods. Larval development lasts 2 or 3 years and may pass through 11 instars.
Size: 20 - 30mm
GB IUCN Status: Not Applicable
GB Rarity Status: Not Applicable
Distribution: England, Scotland
Flight period: June to October
Plant associations: Hardwoods including Fagus spp. (beeches), Ulmus spp. (elms), Ulmus thomasii (Rock Elm), Ulmus glabra (Wych Elm), Acer spp. (maples), Acer rubrum (Red Maple), Acer negundo (Ashleaf Maple), Acer saccharum (Sugar Maple), Quercus spp. (oaks), Carpinus spp. (hornbeams), Robinia spp. (Black Locust), Carya spp. (hickories), Fraxinus spp. (ashes), Platanus occidentalis (American Plane), Malus spp. (apples), Pyrus spp. (pears), Populus spp. (poplars), Salix spp. (willows).
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. D. 1995: Compendium of European Sawflies. List of species, modern nomenclature, distribution, foodplants, identification literature. - Gottfrieding, Chalastos Forestry : 1-190
Musgrove, A.J. 2022. A review of the status of sawflies of Great Britain - Phase 1: families other than Tenthredinidae. Natural England, unpublished
Schiff, N.M., Goulet, H., Smith, D.R., Boudreault, C., Wilson, A.D. and Scheffler, B.E., 2012. Siricidae (Hymenoptera: Symphyta: Siricoidea) of the western hemisphere. Canadian Journal of Arthropod Identification 21: 1-305, 21, pp.1-305.