Hammerschmidtia ferruginea

Hammerschmidtia ferruginea (Fallén, 1817)

Biology & ecology:

The larva is found in wet decaying cambium that builds up under the bark of recently fallen or dead standing trunks and branches of Aspen Populus tremula with a diameter of at least 30 cm. Wet decaying cambium builds up over about four years before the bark cracks and it dries out. Only Aspen stands over 4.5 ha are large enough to maintain the continuity of suitably sized fallen timber needed to support a population of H. ferruginea. Most Aspen stands in Scotland are small, less than 1.5 ha., and only 14 stands extend over 4.5 ha. The species is virtually absent from the numerous smaller stands, especially those over 1km from core areas. Adults visit flowers of Rowan Sorbus aucuparia, Bird Cherry Prunus padus and Hawthorn Crataegus monogyna.


This is a boreal species that is confined to the Highlands of Scotland. The main stronghold is Strathspey between Newtonmore in the south and Grantown in the north. Other sites are in the valley of the Findhorn, Easter Ross, Wester Ross, south-east Sutherland and Deeside.

Status & conservation:

There has been considerable research on the vanishingly small population that now remains and, most recently, this has suggested that adults are vey mobile and that females will travel considerable distances to find breeding sites. Endangered according to  Shirt (1987) and Falk (1991), CRITICALLY ENDANGERED according to Ball & Morris (2014). This is a Biodiversity Action Plan species and was proposed for addition to Schedule 5 of the Wildlife and Countryside Act, 1981 by the 5th Quinquennial Review in 2008 but after consultation, was rejected by the Scottish Government in 2012.

Recorded from 7 hectads since 1990.