Rove beetles, Staphylinidae

Staphylinidae family, rove beetles overview

There are around 55,000 species worldwide, over 5000 species of Staphylinids in Europe, and around 1000 species in the British Isles making this the largest beetle family in the U. K. They are commonly known as rove beetles. They range in size from less than 1 mm to around 30 mm long. The fossil record dates back to the Permian.

The elytra (wing cases) are always short, and this gives the adults a superficial resemblance to earwigs. They are also sometimes confused with beetles from the Silphidae family. However it is really quite easy to tell the two families apart. Silphids have just 3 or 4 exposed segments, and the wing cases are longer than these exposed segments; whereas the Staphs have 3 to 6 exposed segments, and the wing cases are always shorter than the exposed segments.The elytra cover intricately folded wings, and in most species flight is common. It is amusing to watch one just after it has landed, it will wriggle around while its wings are being folded up under the elytra, and only once they are correctly packed away will the beetle move off.

Most of the adults have conspicuous cerci at their rear end. These act just like antennae, and are highly sensitive and useful for a soil-dwelling insect.

Creophilus maxillosus, Hairy rove beetle

Creophilus maxilosus adult rove beetle

Creophilius maxillosus, the Hairy rove beetle, above and below is black with patches of white/yellowish/grey hairs on its elytra (wing cases) and abdomen. Adults range from 15 - 25 mm long. It is found across the northern hemisphere in temperate regions.

Creophilus maxillosus underside

Both the adults and larvae are carnivorous. It feeds on carrion, and the maggots in carrion. It has large eyes, and strong jaws which cross in front (see below) and could easily pierce human skin if mishandled. When it is disturbed it curls up its abdomen and emits a mix of faecal matter and an irritant chemical from glands located on the underside of the tip of its abdomen, smearing this on whatever has disturbed it. It will also curl up into a ball and play dead.

Hairy rove beetle jaws

Staphylinus olens (Ocypus olens), Devil's coach horse, cock-tail beetle

Ocypus olens Devil's coach horse

Above is an adult Staphylinus olens (Ocypus olens), commonly known as the Devil's coach horse or the Cock-tail beetle. With a body length of 22 - 32 mm it is the largest member of the Staphylinidae family found in the U. K. It can be found in woods, gardens and open situations, but tends to favour damp places. During the day it hides under wood or stones. This one was found wandering about in daylight after a thunderstorm, so it had probably been washed out of its hiding place.

Ocypus olens Devil's coach horse

When alarmed it opens its large jaws and curls up its abdomen rather like a scorpion, see above. Its jaws are strong enough to draw blood from humans. Both adult and larva will attack anything. It is a matte black colour. Adults are common from May to September. Despite its size it can, and does fly. Mating takes place in autumn, and the female lays a single egg under a stone or in leaf litter.

Ontholestes tessellatus

Ontholestes tessellatus

Above and below is the adult Ontholestes tessellatus. The adult length ranges from 13 - 20 mm. It is usually found in carrion and dung, but this one was found on the top of a soggy compost heap.

Ontholestes tessellatus

It is truly beautiful, covered in golden hair which has brassy reflections as it moves. Its eyes are huge and its jaws are fearsome. It runs very fast and is not easy to catch.

Below is the larva of Philonthus sp. showing the typical staphylinid larval body shape.

Philonthus sp. rove beetle larva, Staphylinid larva