Ground beetle (Dromius sigma)

Ground beetles belonging to the genus Dromius are typically elongate, flattened beetles ⁽²⁾. Dromius sigma has a black head ⁽²⁾, and pale brown wing cases (elytra) that have a dark 'maltese cross' pattern ⁽¹⁾.

Size

Length: 3.2-4 mm ⁽²⁾

The adults are believed to be wingless in Britain ⁽⁴⁾. The life cycle of this beetle takes one year to complete; breeding is thought to occur in summer, and immature adults overwinter in clumps of tufted hair-grass (Deschampsia cespitosa) ⁽⁴⁾. Both the adults and the larvae prey upon small invertebrates ⁽⁴⁾.

Found in central and eastern England ⁽⁴⁾, but formerly had a very scattered distribution from Cumberland to south Hampshire ⁽⁵⁾. Most recent records are from Yorkshire ⁽⁶⁾.

Inhabits muddy and peaty soils close to standing water in fens, marshes, and flooded gravel pits or quarries ⁽⁴⁾. It is found on soft mud or soil close to the water margin, typically in lush vegetation such as clumps of tall grass ⁽⁵⁾.

Classified as Vulnerable in Great Britain ⁽³⁾

Main threats are the drainage of wetlands for agriculture or development ⁽⁵⁾, as well as peat extraction for use in horticulture ⁽⁴⁾. Further threats are the infilling of gravel pits, tree growth on moorland, and lowered water tables due to water abstraction and river engineering works ⁽⁵⁾.

This ground beetle is included in English Nature's Species Recovery Programme, and is a priority species under the UK Biodiversity Action Plan (UK BAP). The Species Action Plan that has been produced to guide the conservation of this beetle aims to maintain its current range ⁽⁴⁾. A number of sites currently supporting this species are either Sites of Special Scientific Interest (SSSIs) or National Nature Reserves (NNRs); they are therefore afforded a level of protection ⁽⁴⁾. It has been suggested that management for this species should aim to maintain high water tables, and protect water bodies from pollution ⁽⁵⁾.

The UK Biodiversity Action Plan for this species is available at UK BAP.

For more on English Nature's Species Recovery Programme see:
http://www.english-nature.org.uk/science/srp/default.asp

Information authenticated by Dr Martin Luff of the School of Biology, University of Newcastle, with the support of the British Ecological Society:
http://www.britishecologicalsociety.org/

Elytra

In beetles and earwigs, the hard fore wings. They are held aloft when the insect flies, and are often coloured or patterned.

Larvae

Stage in an animal's lifecycle after it hatches from the egg. Larvae are typically very different in appearance to adults; they are able to feed and move around but usually are unable to reproduce.

1. National Biodiversity Network Species Dictionary (September 2002) http://www.nhm.ac.uk/nbn/
2. Lindroth, C. H. (1974) Handbooks for the identification of British insects. Volume IV. Part 2: Coleoptera, Carabidae. The Royal Entomological Society of London, London
3. Shirt, D. B. (1987) British Red Data Books: 2 Insects. Nature Conservancy Council, Peterborough.
4. UK BAP Species Action Plan (September 2002) http://www.ukbap.org.uk
5. Hymen, P. S. and Parsons, M.S. (1992) A review of the scarce and threatened Coleoptera of Great Britain: Part 1. JNCC, Peterborough.
6. Luff, M (2004) Pers. comm.