This species was recognised as occurring in Britain by Liston (1993), since when it has been recorded on just 12 occasions across England north to York with no records from Wales or Scotland to date. Observations appear to have declined in recent years (Musgrove, 2023).
The third antennal segment clearly shorter than the fourth and fifth combined. Hind tibia with white basally (one-third). In the male, the hind tarsus entirely black on basal segment. External face of middle tibia white.
Caliroa tremulae larvae are mucus covered " slugworms" that feed on the underside of aspen leaves. They pupate in the ground.
Size: 4 - 6mm
GB IUCN Status: Vulnerable
GB Rarity Status: Nationally Scarce
Flight period: June to August
Plant associations: Populus tremula (aspen)
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
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 Natural England, unpublished