Xyela julii - Short Daggertail
The three species of Xyela can be difficult to identify from single specimens due to the few available characteristics. Recorded throughout the whole of mainland Britain, including in native pinewoods and more recent plantations. This small species is easily overlooked and may be widespread, but analysis of recent records suggests a decline in recent years (Musgrove, 2022).
Males and females are piceous and more or less marked with yellow. The female head is usually extensively yellow. Adults may be found on neighbouring birch trees when in flower.
Xyela julii larvae feed on the developing pollen in immature male cones causing the cones to become bent out of shape. Several larvae may feed in each cone. They can be swept from birch trees in flower or from herbaceous vegetation at ground level adjacent to pines. Larvae emerge from the cones and drop to the ground to pupate. They hatch the next spring or may enter diapause for two to three years. The pupa has free legs and can run around on the surface before the adult emerges from the exuvia.
Size: approx. 2.5 - 3.5mm
GB IUCN Status: Vulnerable
GB Rarity Status: None
Distribution: England, Scotland, Wales, Ireland
Flight period: Mid-March to mid-May
Plant associations: Pinus spp. (pines) including Pinus sylvestris (Scots Pine), Pinus nigra (Austrian Pine). Scots pine is preferred.
Benson, R.B., 1952. Handbooks for the Identification of British Insects. Hymenoptera, Symphyta, Vol 6, Section 2(a-c), Royal Entomological Society, London
Blank, S.M., 2002. The Western Palaearctic Xyelidae (Hymenoptera), pp. 197-233. In: Viitasaari, M. (editor), Sawflies (Hymenoptera, Symphyta) I. A review of the suborder, the Western Palaearctic taxa of Xyeloidea and Pamphiloidea, Tremex, Helsinki
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 Natural England, unpublished