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Cornish Red Data (2009)

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.

Pterometus staphyliniformis - A ground bug

Range & Status

Although widespread in Europe, from Finland to the Mediterranean, it has only ever been found in Britain in West Cornwall, where it was discovered in the 1960s. It may be overlooked, but it is possibly at the extreme edge of its climatic tolerance in Britain.

Regional Distribution

Recorded in Cornwall only on the western-most coast of West Penwith and is best known between Sennen and Cape Cornwall, where it can be readily found.

Habitat & Ecology

It is associated with the large black ant Formica fusca (which is widespread in Cornwall in suitable habitat) on cliff-top heaths. Originally found in areas of sparse vegetation with thin grass, Stonecrop Sedum spp. and prostrate Clovers Trifolium spp. on rather bare stony ground, but found more recently on lichen-covered boulders in areas of fairly dense scrubby growth of Common Gorse Ulex europaeus and Bramble Rubus fruticosus agg. It is probably a seed feeder.


Abandonment of cliff grazing is the main threat at present, leading to a coarsening and thickening of vegetation. Trampling pressure is probably important in the absence of grazing.


Scrub clearance and grazing restoration are important conservation measures. Much of this coast is now owned by The National Trust and lies within a SSSI.


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.