Dolerus ferrugatus - Rusty Mourner

Recorded widely across all of mainland Britain (Musgrove, 2023).

In the female the side lobes of the mesonotum are entirely black in contrast to the usually orange middle lobe and pronotum and orange abdomen. The legs are black.

Males appear to be commoner than females. In the male, the mesonotum is entirely black. The abdomen is yellow except for the black first tergite and apical tergites. The Males can be separated from those of Dolerus madidus by the mesopleura, which are heavily sculptured into a honeycomb of craters, and the shape of the penis valves.

Dolerus ferrugatus larvae feed on rushes in moist habitats including Soft Rush (Juncus effusus).

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GB IUCN Status: Least Concern
GB Rarity Status: None

Distribution: England, Scotland, Wales, Ireland

Flight period: Apr to June

Plant associations: Juncus sp. (rushes)

References:

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 Natural England, unpublished