Stag beetle (Lucanus cervus)

KingdomAnimalia
PhylumArthropoda
ClassInsecta
OrderColeoptera
FamilyLucanidae
GenusLucanus
SizeMale body length: 25-75 mm
Female body length: 30-45 mm

Ths stag beetle is listed under Annex II of the EC Habitats Directive and Appendix III of the Bern Convention. Protected in the UK under Schedule 5 of the Wildlife and Countryside Act 1981, as amended.

The stag beetle (Lucanus cervus) is arguably the most spectacular looking beetle in Britain; the male looks like something from a prehistoric age. The giant antler-like mandibles are used in courtship displays, and wrestling with other males. Although rather fearsome in appearance, the mandibles cannot be closed with any force. You are more likely to be nipped sharply by the female stag beetle, a smaller insect than the male that lacks the huge jaws. The stag beetle, superficially, appears black all over but, in certain lights, it can be seen to have dark maroon or brown wing cases. The impressive mandibles also have a reddish sheen to them. The wing cases are glossy; the head and thorax are a dull black.

The stag beetle is nothing like as common as it used to be, but is still widespread in southern England, especially the Thames valley, north Essex, south Hampshire and West Sussex. It also occurs fairly frequently in the Severn valley and coastal areas of the south-west. Elsewhere in Britain it is extremely rare or even extinct. This beetle is found throughout Europe, and East Asia as far as Japan, although it is rare or declining in some countries.

Stag beetles are found in gardens, wooded parks and pasture woodland; anywhere where there is a good supply of dead wood.

Despite it being such a large and spectacular insect, surprisingly little is known about the habits of the stag beetle. In 1998 the People's Trust for Endangered Species (PTES) invited the public to look for the beetles, asking questions about where they were finding them, the type of wood it was found near, was it eating and so-on. The 'Stag Hunt' revealed that the beetles lay their eggs both in rotting log piles and in the roots of an assortment of rotten trees, including oak, apple, ash and cherry. They seem to have a preference for oak, especially those growing along riverbanks. They also prefer warm places on sandy or light soils, and are now mostly reported from urban and suburban gardens. In fact, seventy percent of the beetles reported were found in gardens.

The larvae of the stag beetle live within their rotting logs for up to four years before pupating and emerging as adults at the beginning of the flight season the following year. However, the adults have a much shorter life than the larvae, and only survive for a few months. It used to be thought that adult stag beetles died at the end of the year but, as a result of the survey, it seems some beetles can survive the winter. The main message from the survey was, sadly, that the beetle seems to have declined in numbers greatly, especially in some areas.

As the beetle grubs take so long to develop, they become extremely vulnerable to tree clearance and the 'tidying up' of wood in parks and especially gardens; the over-zealous tidying of dead timber and stumps is thought to be the chief reason why this spectacular beetle seems to be in decline; although facts about its true status are still unclear. Elsewhere, there may also be a threat caused by the collection of the beetles for sale; to date no evidence of such a trade has been found in the UK. There are a number of websites that offer specimens for sale in the US for about $10 per animal. Whether they are collected from the wild or bred for the purpose is not clear, but if it does occur this practice is probably limited to European countries.

The stag beetle is listed as a priority species under the UK Biodiversity Action Plan (UK BAP), and is included in English Nature's Species Recovery Programme. The People's Trust for Endangered Species is leading a number of programmes to raise the profile of this insect, and have now organised two national surveys to find out more about stag beetle distribution and behaviour and encourage the public to become more sympathetic towards them; the huge response to the first PTES survey suggests that the beetles now have an enthusiastic fan club who may lobby local authorities and owners of large gardens to 'spare that rotten tree!'

With regard to the fear that trade in the insects might present a threat, the PTES lobbied the government's advisors and, since April 1998, the stag beetle has been protected under Schedule 5, Section 9.5 of the Wildlife and Countryside Act 1981, which means that all trade in the species is illegal and those suspected of trading in the species can be prosecuted.

For more on the People's Trust for Endangered Species: 
http://www.ptes.org/

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
arkive@wildscreen.org.uk