With unconfirmed older records from York, Norfolk and Speyside, the first confirmed individuals were found between 2016 and 2022 in the vicinity of Woking (Halstead 2018). The highly localised nature of the three latter records to date are suggestive of an introduced species.
Cladardis elongatula is an entirely black insect with the head and thorax shining with very fine punctures. Although normally black, the front of the fore and middle knees may be brownish or the entire front face of the foreleg paler.
Eggs are laid onto leaf petioles from where larvae bore into the stems of roses. Larvae bore upwards from the entrance hole, for a distance of up to 15cm, causing wilt (similar damage is caused by Ardis spp.).
Size: 6 - 8mm
GB IUCN Status: Rare
GB Rarity Status: Rare
Flight period: May to July
Plant associations: Rosa spp. (roses)
Benson, R.B., 1952. Handbooks for the Identification of British Insects. Hymenoptera, Symphyta, Vol 6, Section 2(a-c), Royal Entomological Society, London
Halstead, A.J., 2018. Two stem-boring sawflies new to Britain, Janus compressus (Hym.: Cephidae) and Cladardis elongatula (Hym.: Tenthredinidae), British Journal of Entomology and Natural History, Vol 31(1), BENHS, Reading.
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. 2023. A review of the status of sawflies of Great Britain - Phase 2: The Athaliidae and the Tenthredinidae (excluding Nematinae). Natural England, unpublished