Ground beetle (Pterostichus aterrimus)

GenusPterostichus (1)
SizeLength: 13 - 15 mm (2)

Classified as Endangered in Britain (3).

Pterostichus aterrimus is a large and shiny black ground beetle that has curved edges to the pronotum(2). The wing cases (elytra) are covered in deep pits, the presence of which allows this species to be distinguished from the very common ground beetle Pterostichus madidus (4).

This beetle was found in the Norfolk Broads, East Anglia until 1910 (3). It was recorded as in the New Forest from 1969 to 1973 at a site that has since dried out and become unsuitable for the species (3). It was discovered in Northern Ireland in County Armagh in 1982, where it persists today at 7 sites (3) (4). Elsewhere, this species is found in western and central Europe, reaching into western Siberia. A few populations also occur in north Africa (2).

Inhabits wet fens and bogs close to water on peaty or muddy soils (5).

Little is known of the biology of this beetle. Both the adults and the larvae are predatory. Adults have functional wings, and they have been seen flying. This species has an annual life-cycle, with breeding occurring in spring. The larvae are present in summer (3).

Factors responsible for the decline in this species are thought to include widespread drainage of peat bogs and fens (4), as well as water abstraction (3).

This beetle is listed as a priority species under the UK Biodiversity Action Plan and a Species Action Plan has been produced to coordinate conservation. This plan aims to maintain the current populations, as well as restore the species to at least two appropriate sites within the historic British range before 2010 (3).

Information authenticated by Dr Martin Luff of the School of Biology, University of Newcastle, with the support of the British Ecological Society:

  1. NBN Species Dictionary. (Feb 2003). Available on-line from:
  2. Anderson, R. & McFerran, D. (2001) The Ground Beetles of Ireland.
  3. UK BAP Species Action Plan for Pterostichus aterrimus. (November 2003):
  4. Shirt, D. B. (1987) British Red Data Books: 2 Insects. JNCC, Peterborough.
  5. Luff, M. (2004) Pers. comm.