Help find Britain's disappearing oil beetles

The short-necked oil beetle. Picture: John Walters

Number of beetles has halved in past century

March 2011: The first ever nationwide survey to map the location of the threatened oil beetles is underway - and organisers want the public to help. The survey was launched earlier this month by Buglife - The Invertebrate Trust and the National Trust in partnership with Natural England and Oxford University Museum of Natural History.

Often found on the coast, and particularly in the south west of England, the number of oil beetle species found in the UK has halved in the past 100 years and the survey will help establish the whereabouts of the remaining four species and boost efforts to secure their future.

Buglife is asking people to keep a look out for oil beetles this spring and has provided a wealth of information for those interested in taking part. Visit the Buglife website for a free identification guide, more information about these beautiful beetles and to report sightings and photographs.

Beetles have been hit by a ‘double whammy'
Buglife's Conservation Officer, Andrew Whitehouse, said: ‘Oil beetles have been hit by the double whammy of flower-rich habitats disappearing from our countryside and a drastic reduction in populations of wild bees - upon which the beetles depend to complete their life cycles.

The black oil beetle. Picture: Ben Lee

‘With the public's help we can get a better understanding of the distribution of four species of oil beetle found in England, helping our efforts to enhance habitats to secure their survival.'

Four species of oil beetle remain in UK
There are four oil beetle species found in the UK: the black oil beetle (Meloe proscarabaeus), violet oil beetle (Meloe violaceus), rugged oil beetle (Meloe rugosus) and short-necked oil beetle (Meloe brevicollis). All of these beetles are at risk of disappearing from our countryside and the short-necked oil beetle was thought to be extinct until it was rediscovered on National Trust land in South Devon in 2007.

The adult oil beetles will lay up to 1,000 eggs in a burrow in soft or sandy soil which hatch a month or so later. The young larvae are unusual in being very active and long-legged and are known as triungulins after their three claws.

The violet oil beetle. Picture: David Fenwick

Once hatched, the larvae crawl up on to vegetation, often lying in wait in flowers, where they hitch a ride on mining bees and are involuntarily taken back to the bee's nest. The triungulin then changes into a more maggot like larvae and devours the bee's egg and also the protein-rich pollen stores that the bee intended to provide for its own larvae. Adults emerge in the following spring, completing the lifecycle. 

Oil beetles are normally found between late March and June. They can be found on wildflower-rich grasslands, heathland, moors and coastal areas such as cliff tops.

'It makes you realise what a miracle each and every beetle is'
TV Presenter and Buglife Vice President Nick Baker is a huge fan of oil beetles. He said: ‘They're big, bold beetles with a lustre that would put any oil droplet to shame. They are also very unique in their highly complex life cycle and when you get to know them, it makes you realise what a miracle each and every beetle is. Oil beetles are also one of our most charismatic insects and are an icon of our wildflower grasslands.

The rugged oil beetle. Picture: John Walters

‘Look out for them this spring and if you are lucky enough to discover one ambling along, take the time to enjoy it and then pass on the details of your experience to Buglife as every record received will go a long way to helping us understand these beautiful beetles.'

Andy Foster, an ecologist at the National Trust, said: ‘Female oil beetles like to dig their burrows in bare ground on the edge of footpaths so they are easy to see, and this is a great opportunity for the public to send in sightings and help us understand more about them.

‘Buglife and the National Trust are erecting "don't step on the beetles" signs at oil beetle hotspots to remind visitors to look where they step and to send in their oil beetle sightings to the survey.'