Heptamelus ochroleucus - Pale Shorthorn
This species appears to be widespread. However, historic records need critical re-examination, due to the omission of Heptamelus dahlbomi by Benson. Vikberg & Liston (2009) confirm about 20 specimens, mostly from Scotland but some in England and Wales, apparently based mostly on examination of the collections at the Royal Scottish Museum (Edinburgh). A number of recent Norfolk records have also been clearly identifiable as ochroleucus s.s. (Musgrove, 2022).
The female is largely black. The labrum and palps are off-white. Mandibles reddish-brown. The upper edge of the pronotum usually marked pale. The mesonotum marked with brown and the mesopleuron with a thin pale stripe on the upper side of the mesopleural groove. Sternites extensively pale. Legs mostly pale. The stigma is pale brown and the costa off-white.
Males occur in similar numbers to the females. The male differs in having pale antennae to some degree. The thorax and abdomen are extensively yellowish-brown
Heptamelus ochroleucus larvae feed within the petiole of fern leaves.
Size: Female: 4.8 - 5.5mm, Male: 3.6 - 5.2mm
GB IUCN Status: Data Deficient
GB Rarity Status: Nationally Rare
Distribution: England, Scotland, Wales, Ireland
Flight period: May to late-August
Plant associations: Filices (ferns) including Athyrium filix-femina (Lady-fern), Blechnum spicant (Hard-fern), Polypodium vulgare (Polypody), Dryopteris dilatata (Broad Buckler Fern)
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. 2022. A review of the status of sawflies of Great Britain - Phase 1: families other than Tenthredinidae. Natural England, unpublished
Vikberg, Veli & Liston, Andrew. (2009). Taxonomy And Biology Of European Heptamelini (Hymenoptera, Tenthredinidae, Selandriinae). Zootaxa. 2112. 1-24. 10.5281/zenodo.187915.