On this page, Overview - Nicrophorus (Necrophorus) humator, the sexton or black burying beetle - Nicrophorus investigator - Oiceoptoma throracica the red-breasted carrion beetle - Aclypea opaca
These are the carrion or burying beetles. There are 30 species in Europe, and 21 in the U. K. The fossil record goes as far back as the Jurassic. The adults range in length from 1.5 - 40.0 mm long, although most measure over 10 mm long. Usually the adults have club antennae that is thicker at the tip than at the base - see below. The sensory hairs in the club end enable them to locate decomposing flesh at great distances. Beetles in this family are sometimes confused with the Staphylinidae family because some Silphids have a few segment of the abdomen exposed by the shorter wing cases. 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 adults are good fliers.
Not all of them live off carrion as some of them do eat plants and decaying vegetation. Those that do live off carrion have a good sense of smell. Beetle collectors used to take advantage of this by putting out a small carcass to attract the adults.
Below is the typical shape of the Silphidae larva, which resembles a woodlouse.
Nicrophorus (Necrophorus) humator, the sexton or black burying beetle above and below. The adult is 18 - 26 mm long. It is fairly common throughout central and northern Europe. The adult has strongly clubbed antennae with an orange tip, and the last few segments of its abdomen are exposed. The adults bury carrion and small dead animals as food for themselves and their larvae. Adults are most commonly seen between April and October.
The beetles usually arrive singly at carrion. The first male and female will fight off later arrivals. Then they bury the carcass by removing the soil beneath it. They frequently skin it and may even amputate limbs to make the burying easier. Next the female digs a small passage off from the carcass and lays her eggs. Then she returns to feed on the corpse. During this time the male may remain or he may leave. She feeds the grubs by regurgitating liquid food until they can feed off the carcass themselves.
The larvae can be up to 33 mm long, and are creamy yellow with dark brown parches on each segment. They pupate in individual cells hollowed out just off the carcass chamber.
I found this specimen dead on my patio and covered by these little mites.
The mites are usually found on the underside of live beetles, and do no harm to the beetle. They prey on blowfly eggs and larvae and worms in dung and carrion, and use the beetles to transport them to food sources. So you could say they actually help the beetles keep the carcase all to themselves.
Above and below is Nicrophorus investigator another burying beetle in the Silphidae family. Its habits and life cycle are similar to Nicrophorus humator above. This is the most common burying beetle you are likely to come across in woods.
Note the distinctive orange bands on the elytra and on the underside of the thorax a row of long yellow hairs. This specimen I found dead near my rubbish bin. Like the one above it was covered in little mites - for more on this see the photograph below.
Adult length is 18-22 mm. Adults can be seen from June - September.
In this photograph below you can see a live Nicrophorus investigator, or rather you cannot see it as it is completely obscured by mites. It was crawling along the side of a woodland path, going at quite a rate. I picked it up, but put it down fairly quickly as the mites started to run all over me!
Oiceoptoma throracica, above is 11 - 16 mm long, and is the only carrion beetle in the U. K. with an orange/red pronotum. It can be found right across Eurasia.
It is usually found on carrion, but is also fond of the stinkhorn fungus. I found this one dying by the roadside. I think it may have been hit by a passing car. You can see part of its wing sticking out of the elytra. Adults are seen from May - September.
Silpha atrata, above and below, also known as Phosphuga atrata is usually black, but there are brown varieties. Adult body length is 10 - 15 mm. It has a
long head which is useful when eating its favourite prey of snails. The adults have a poisonous bite, but are no danger to humans. It is common in many habitats. And is usually found in moss or under loose bark.
The larva also feeds on snails.
Aclypea opaca, above, is also known as Blitophaga opaca and Silpha opaca. The adult length is 9 - 12 mm, and it is covered in golden hairs. It is vegetarian and eats beet and turnips as both larva and adult. It is found over the whole holoarctic region.
The larva is the typical woodlouse-shaped Silphid type (see the drawing at the top of the page), and is shiny black with a yellow edge.
The eggs are laid in the soil in May or June, and it has one generation a year. The time from egg to adult takes about a month, and it pupates in the soil. It overwinters as an adult in litter or woodland edges in sunshine.