Acantholyda erythrocephala - Red-headed Pine Spinner

Acantholyda erythrocephala, the red-headed pine sawfly, also called the pine false webworm, is an easy to recognise species. Recorded sparsely but widely from Caledonian pine forest fragments for many years. The species was absent elsewhere in Britain until the year 2000, since when it has been recorded widely in the south-east in more recently planted pines (Musgrove, 2022)

The female is a glossy black insect with a blueish reflection and a striking red, or orange-yellow head. The male is similarly coloured but only the face and fore-tibiae are orange-yellow.

Females lay eggs in rows on the previous year's pine needles and the larvae spin silk tubes from which they feed. Once mature, the larvae fall to the ground and overwinter as a prepupa in the leaf litter.

Jump to other Pamphiliidae

Size: 10 - 12mm

GB IUCN Status: Least Concern
GB Rarity Status: None

Distribution: England, Scotland

Flight period: April to June

Plant associations: Pinus spp. (pines) including Pinus sylvestris (Scots Pine), Pinus nigra (Austrian pine), Pinus strobus (Weymouth pine), Pinus cembra (Arolla pine). Scots Pine is reported as the preferred food plant.


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.

Musgrove, A.J. 2022. A review of the status of sawflies of Great Britain - Phase 1: families other than Tenthredinidae. Natural England, unpublished

Viitasaari, M. ed., 2002. Sawflies (Hymenoptera, Symphyta), I: a review of the suborder, the Western Palaearctic taxa of Xyeloidea and Pamphilioidea (Vol. 1). Tremex Press.