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Hammerschmidtia ferruginea (Fallén, 1817)

Identification

Identification difficulty = 2. eyeball_icon camera_filled_icon according to Ball & Morris, 20241

Biology

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. Recent mark, release, recapture experiments suggest that this quite a mobile species and will travel some distance to find suitable breeding sites.

Flight period

The following plots show the number of unique records per week that were not reported to be of eggs, larvae or pupae. phenology

Status

CRITICALLY ENDANGERED - Ball & Morris, 20142. Endangered (RDB1) - Falk, 19913 and Shirt, 19874.

Distribution

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. dotmap

  1. Ball, S., & Morris, R. (2024). Hoverflies of Britain and Ireland. WILDGuides (3rd ed.). Oxford: Princeton University Press. ↩

  2. Ball, S., & Morris, R. (2014). A review of the scarce and threatened flies of Great Britain. Part 6: Syrphidae. ( No. 9). Species status (pp. 1–130). Peterborough: JNCC. ↩

  3. Falk, S. (1991). A review of the scarce and threatened flies of Great Britain. ( No. 39). Research and Survey in Nature Conservation (pp. 1–194). Peterborough: NCC. ↩

  4. Shirt, D. (Ed.). (1987). Red Data Books: 2. Insects. Peterborough: NCC. ↩