The violet click beetle (Limoniscus violaceus) is a 12 millimetre long black beetle with a faint blue reflection. It gets its name from the family habit of springing upwards with an audible click if it falls on its back. There are some 160 species living in Europe and their ability to 'click' themselves back on their feet is due to some interesting insect mechanics. Underneath members of the click beetle family is a groove and a peg. If the beetle finds itself inverted it puts a powerful muscle under tension. The peg is slammed into the pit and the contraction throws the beetle into the air, producing the audible click. The larvae, in common with other family members are known as 'wireworms' because of their proportions, and their colour, which is like rusty wire.
Very little is known of the habits of the violet click beetle, beyond that of its preferred habitat. There is a possible association with bird and animal nests, and it is thought that adult beetles are nocturnal, and feed on plant nectar.
The violet click beetle is extremely rare. It is found in only a few locations in Europe and at three sites in Britain. One of these is in Windsor Forest, another on Bredon Hill in Worcestershire, and the third is a small wood in Gloucestershire.
The violet click beetle is found only in the heart of very old and decayed trees. However, it only seems to favour trees where the decaying wood has attained a consistency like damp soot. This condition tends to be very rare in most woods, and in Britain has only been found in beech and ash trees.
The violet click beetle has always been rare in the UK in historic times, and has not been found in the sub-fossil record to date. This suggests it has been rare for a very long time. However, the particular conditions the beetle requires are hardly ever found, and the felling of old trees for safety reasons means that its habitats are becoming even rarer.
Efforts in the UK have concentrated on providing more sites for the violet click beetle. There are few suitable trees on the British sites at Bredon Hill and Windsor. Some trees were found to contain larvae but none of the others seemed likely to provide the right conditions. Following the great storm of 1987, one old hollow beech in Windsor Forest blew down. Ted Green, the (then) warden, managed to re-erect it by using another living tree as support and then began to experiment with various 'rotting' ingredients to attempt to create the conditions needed by the violet click beetle. After seven years, Ted's efforts bore fruit and five larvae were found inside his prepared tree. Plans are well under way to erect and prepare more suitable trees and even artificially 'age' some. This is taking place with the help of dead wood invertebrate and fungus specialists as part of English Nature's Species Recovery Programme.
The UK Biodiversity Action Plan for this species is available at UK BAP.
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