The descriptive text, below the map, is from the Cornish Red Data Book (2009). The map on this web page depicts the organisms distribution and shows the records made pre-2000 and those made since.
Range & Status
Probably extinct in Britain (Thomas, 1991), although other commentators regard it as extremely rare with disjunct fluctuating populations (Emmet & Heath, 1989). The situation is confused by a number of releases bred from local continental stock (M.S. Warren, pers. comm.). Widespread in central and southern Europe. There have been recent unpublished claims (2008) that it is present near Plymouth, but these records cannot be accepted without proof.
The only confirmed recent record is of a parasitised larva on Cubert Common in 1983. Although it has been recorded in southern Cornwall and on the Isles of Scilly, there is no definite proof that it was ever resident here. Recent unconfirmed sightings may be escapes (or deliberate releases) from captive stock.
Habitat & Ecology
Females lay on Elms Ulmus spp., especially Wych Elm Ulmus glabra . Elms are common and widespread in Cornwall. Willows Salix spp. and other trees are also used.
Dutch elm disease is sometimes given as a cause of decline (Dennis, 1992), and certainly this disease has seriously affected Elms in Cornwall.
I.J. Bennallick, S. Board, C.N. French, P.A. Gainey, C. Neil, R. Parslow, A. Spalding and P.E. Tompsett. eds. 2009. Red Data Book for Cornwall and the Isles of Scilly. 2nd Edition.Croceago Press.
The Cornish Red Data Book Project was led by the Cornwall and Isles of Scilly Federation for Biological Recorders (CISFBR). The full text and species accounts (minus the maps) are available on the CISFBR website.