Xeris spectrum - Dark-hipped Woodwasp
On examination by Goulet et al, all specimens of British material in the British Museum of Natural History were determined to actually be Xeris pallicoxae. Therefore, all historical records should be viewed with caution. A 2020 record from Oxfordshire appears superficially correct for spectrum on the basis of its fore coxae colour. The species is confirmed as present in Britain after a specimen was taken in Bedfordhire in 2022 adjacent to mature Scots pine woodland (Musgrove, 2022). There may be additional Xeris spectrum specimens in private collections and municipal collections.
In pallicoxae the yellowish-white band on the pronotal shoulders is largely smooth between raised peaks, whereas in spectrum the bands are heavily ridged. In lateral view the pronotum of pallicoxae has only sparse pits, whilst spectrum has numerous coarse pits over at least one third of the area such that the margins form raised reticulation. The female has black coxae on at least on their outer face (reddish-brown in pallicoxae).
The male has a large yellowish-white spot, quite sharply outlined, extending beyond the genal carina onto the occiput (comma shaped). There is a wide reddish-brown band on the basal hind tarsal segment and the third to fifth tarsal segments are similarly reddish-brown.
Larvae feed in the timber of coniferous trees and take 2 or 3 years to emerge.
Size: 15 - 30mm (excl. ovipositor)
GB IUCN Status: Data Deficient
GB Rarity Status: Unclear
Distribution: England, Wales, Ireland
Flight period: June to October
Plant associations: Pinaceae (coniferous trees) including Abies spp. (firs), Abies alba (European Silver-fir), Abies cilicia (Cilician Fir), Larix decidua (European Larch), Picea spp. (spruces), Picea abies (Norway Spruce), Picea orientalis (Japanese Spruce), Picea sitchensis (Sitka Spruce), Pinus spp. (pines), Pinus pinaster (Maritime Pine), Pinus sylvestris (Scots Pine).
Benson, R.B., 1952. Handbooks for the Identification of British Insects. Hymenoptera, Symphyta, Vol 6, Section 2(a-c), Royal Entomological Society, London
Goulet, H., Boudreault, C. and Schiff, N.M., 2015. Revision of the world species of Xeris Costa (Hymenoptera: Siricidae). Canadian Journal of Arthropod Identification, 28.
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