This was one of the very first beetles I learned to identify when I was a little boy. I know what you are thinking, that is not a beetle, surely? But it is, and let’s see, it is quite an interesting beetle.
This is Britain’s largest rove beetle and can grow up to 30mm (1 3/16inch) in length. It is all black and covered in fine black hairs. It has short wing cases and can fly although it rarely does. The extended abdomen is made up of eight segments which are covered in hard plates. It raises its abdomen much like a scorpion raises its tail when threatened which has earned it the title of the ‘Cocktail Beetle’. It also opens its strong mandibles which makes its quite a fearsome beetle.
The adults and the larvae are very ferocious predators feeding at night on slugs, worms, woodlice, and other invertebrates. It seizes its prey in its powerful mandibles. They do not sting, but can give a nasty bite.
Seen all year round, and found in woodland, hedgerows, parks, gardens and outbuildings. Occasionally found indoors in houses. It hides amongst leaf litter, or beneath logs and stones in the daytime. Common and widespread throughout.
In the image below you can see how fearsome these beetles can be. This is the larva of a Devil’s Coach-horse attacking an earthworm. Please click on the image for more information and photos.
July 2013, rear garden, Staffordshire. © Pete Hillman 2013.