Cosmia diffinis

Range & Status

This species has suffered a rapid decline in recent years, with scattered records in southern Britain and Wales from East Anglia to Cornwall (Waring, 1992). It is local in western Europe from northern Spain to the Netherlands (Heath & Emmet, 1983).

Regional Distribution

Recorded in Cornwall only at Menabilly (Wild & Marshall, 1973) and Welcombe and Marsland nature reserve. It has probably suffered in Cornwall as elsewhere from the destruction of Elms Ulmus spp. by Dutch elm disease, especially since it is less likely to be found away from its foodplant than other Cosmia species (Heath & Emmet, 1983).

Habitat & Ecology

The larvae feed on Wych Elm Ulmus glabra and perhaps Cornish Elm Ulmus minor . Nationally, it is closely associated with Common or English Elm Ulmus procera , which probably does not occur in Cornwall. The adults fly in August.

Threats

Dutch elm disease.

Conservation

Planting of Elms in suitable habitat in VC2. A UK BAP priority species.