Historically the two Kaliofenusa species were only separated in Britain in 1994. There appears to be little morphological or genetic difference between the species of Kaliofenusa and some authors now consider Kaliofenusa species as a single species under the name Kaliofenusa pusilla. In the 2023 status review, the two species were treated as one under the name ulmi.
Widely recorded throughout all of mainland Britain, as well as on Skye (Musgrove, 2023).
Normally, Fenusa ulmi is an entirely black species. In the female, the sawsheath appears to be unreliable for identification. In this species the frons has lateral walls that are almost straight-sided and lateral foveae are contained within elongated, narrow furrows that extend above the frontal furrow.
Eggs are deposited in the mid-veins of wych elm from where the larva forms a blister mine that often does not reach the leaf margin. The Kaliofenusa species appear to prefer suckers and regrowth.
Size: 3 - 4mm
GB IUCN Status: Least Concern
GB Rarity Status: None
Distribution: England, Scotland, Wales, Ireland
Flight period: Bivoltine? April to June and August.
Plant associations: Ulmus glabra (wych elm)
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. D. 1994. Kaliofenusa carpinifoliae LIston (Hymenoptera: Tenthredinidae), a newly recognised leafminer on field elms in Britain. British Journal of Entomology and Natural History, vol.7 (1), pp15-18.
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 Natural England, unpublished