The violet click beetle (''Gambrinus violaceus'', formerly ''Limoniscus violaceus'') is a black

beetle Beetles are insects that form the Taxonomic rank, order Coleoptera (), in the superorder Holometabola. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 40 ...

, long, with a faint blue/violet reflection. It gets its name from the family habit of springing upwards with an audible click if it falls on its back. It occurs in Europe.

Description

The adult beetle is long and slender, about long, with many small puncture marks on its

pronotum The prothorax is the foremost of the three segments in the thorax of an insect, and bears the first pair of legs. Its principal sclerites (exoskeletal plates) are the pronotum (dorsal), the prosternum (ventral), and the propleuron (lateral) on e ...

, and longitudinal striations on its

elytra An elytron (; ; : elytra, ) is a modified, hardened forewing of beetles (Coleoptera), though a few of the true bugs (Hemiptera) such as the family Schizopteridae are extremely similar; in true bugs, the forewings are called hemelytra (sometime ...

. The pronotum is greyish-black and the elytra are black with a purplish iridescence. The

larva A larva (; : larvae ) is a distinct juvenile form many animals undergo before metamorphosis into their next life stage. Animals with indirect development such as insects, some arachnids, amphibians, or cnidarians typically have a larval phase ...

e are whitish and resemble

mealworm Mealworms are the larval form of the yellow mealworm beetle, ''Tenebrio molitor'', a species of darkling beetle. The yellow mealworm beetle prefers a warmer climate and higher humidity. Male mealworm beetles release a sex pheromone to attract ...

grubs.

Ecology

This sapro-xylophagous beetle is found only in the heart of decayed ancient trees, specifically in undisturbed wood-mould at the base of central cavities: in Britain it has been found only in

beech Beech (genus ''Fagus'') is a genus of deciduous trees in the family Fagaceae, native to subtropical (accessory forest element) and temperate (as dominant element of Mesophyte, mesophytic forests) Eurasia and North America. There are 14 accepted ...

and

ash Ash is the solid remnants of fires. Specifically, ''ash'' refers to all non-aqueous, non- gaseous residues that remain after something burns. In analytical chemistry, to analyse the mineral and metal content of chemical samples, ash is the ...

trees. Its very specific habitat requirements mean that the beetle is very rare, and even at the three sites where it has been found, there are few suitable trees, and their number is declining. One of the host trees at Windsor blew down in the Great Storm of 1987, but was re-erected solely as a host for the violet click beetle.

English Nature English Nature was the Executive agency, United Kingdom government agency that promoted the Conservation (ethic), conservation of wildlife, geology and wild places throughout England between 1990 and 2006. It was a non-departmental public body ...

's conservation efforts continue in an effort to create more suitable trees, including by erecting more decaying trees, and artificially ageing some others. Windsor Forest is considered to be the most important site in Britain for invertebrates associated with the decaying timber of ancient trees. In Hungary, the larvae occupy cavities filled with wood mould near the base of hollow Turkey oaks (''

Quercus cerris ''Quercus cerris'', the Turkey oak or Austrian oak, is an oak native to south-eastern Europe and Asia Minor. It is the type species of ''Quercus'' sect. ''Cerris'', a section of the genus characterised by shoot buds surrounded by soft bristles, ...

''), but also in similar cavities in lime (''

Tilia ''Tilia'' is a genus of about 30 species of trees or bushes, native throughout most of the temperateness, temperate Northern Hemisphere. The tree is known as linden for the European species, and basswood for North American species. In Great Bri ...

''), ash (''Fraxinus'') and maple ('' Acer'') trees.

Conservation status

The

International Union for Conservation of Nature The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the stat ...

has assessed the conservation status of the beetle as

Endangered An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching, inv ...

. The beetle is listed in Annex II of the EC Habitats Directive and Schedule 5 of the UK's Wildlife and Countryside Act 1981. It is also listed as Endangered in the GB Red List. It is to be found in only a few locations in Europe, including three sites in

Britain Britain most often refers to: * Great Britain, a large island comprising the countries of England, Scotland and Wales * The United Kingdom of Great Britain and Northern Ireland, a sovereign state in Europe comprising Great Britain and the north-eas ...

. These are

Windsor Forest Windsor may refer to: Places *Detroit–Windsor, Michigan-Ontario, USA-Canada, North America; a cross-border metropolitan region Australia New South Wales *Windsor, New South Wales ** Municipality of Windsor, a former local government area Queen ...

(where it was first found in 1937),

Bredon Hill Bredon Hill is a hill currently located in Worcestershire, England, south-west of Evesham in the Vale of Evesham. The summit of the hill is in the parish of Kemerton, and it extends over parts of eight other parishes (listed below). The hill i ...

Worcestershire Worcestershire ( , ; written abbreviation: Worcs) is a Ceremonial counties of England, ceremonial county in the West Midlands (region), West Midlands of England. It is bordered by Shropshire, Staffordshire, and the West Midlands (county), West ...

(1989), and Dixton Wood SSSI in

Gloucestershire Gloucestershire ( , ; abbreviated Glos.) is a Ceremonial counties of England, ceremonial county in South West England. It is bordered by Herefordshire to the north-west, Worcestershire to the north, Warwickshire to the north-east, Oxfordshire ...

(1998). The violet click beetle is one of the species that the Back from the Brink project aims to save from extinction in Britain.

References

{{Taxonbar, from=Q632115 Dendrometrinae Beetles described in 1821 Habitats Directive species