Rhogogaster chambersi - Flax Carver, Flax Sawfly

Recorded widely if locally from Yorkshire southwards, with isolated records further north in Scotland (Musgrove, 2023).

One of three small species included in the Rhogogaster picta group. All three have bicolorous blue-green/black stigma. Rhogogaster chambersi has both male and female genders. The hind tibia are lined with black on the anterio-dorsal face. Facial markings and saw teeth are diagnostic (see Benson). Most of the stigma is pale.

Larvae feed on Fairy Flax and cultivated Flax. Several eggs are lain into the upper surface of leaves of this small plant causing obvious blisters. Larvae nibble at leaves. There are three or four larval instars prior to the prepupal stage and larvae feed for 30 to 50 days. The prepupa burrows without delay into the soil.

Jump to other Rhogogaster species

Size: 6 - 8.5mm

GB IUCN  Status: Least Concern
GB Rarity Status: None

Distribution: England, Scotland, Wales

Flight period: May to July

Plant associations: Linum catharticum (Fairy Flax) and cultivated Flax.

References:

Benson, R.B., 1952. Handbooks for the Identification of British Insects. Hymenoptera, Symphyta, Vol 6, Section 2(a-c), Royal Entomological Society, London

Chambers, V. H. 1951: The larva and foodplant of Rhogogaster chambersi Benson (Hym., Tenthredinidae). - The Entomologist's Monthly Magazine, Fourth Series, London 87(12): 202-205

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

Liston, A. D. 2015: New records and host plants of Symphyta (Hymenoptera) for Germany, Berlin and Brandenburg. - Contributions to Entomology. Beiträge zur Entomologie, Keltern 65(2): 383-391

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 Natural England, unpublished