Burying Beetle

Burying beetles (Silpha vespillo) belong to the Silphidae family. Most of these beetles are black in colour and have red markings on their elytra. Burying beetles bury the carcasses of small vertebrates such as birds and rodents as a food source for their larvae. Burying beetles are unusual among insects in that both the male and female participate in parental care for their young.

Burying beetles have large club-like antennae equipped with chemoreceptors (a sensory receptor) capable of detecting a dead animal from afar. After finding a carcass (most likely that of a small bird or a mouse), beetles fight amongst themselves (males fighting males, females fighting females) until the winning pair (usually the largest) remains.

If a lone beetle finds a carcass, it can continue alone and wait for a partner. The carcass must be buried by the beetles to get it out of the way of potential competitors, which are numerous. The burial process can take around 8 hours.

Single males attract mates by releasing a pheromone (a chemical that triggers a natural behavioural response in another member of the same species) from the tip of their abdomens. Females can raise a brood alone, fertilizing her eggs using sperm stored from previous copulations.

The female burying beetle lays eggs in the soil around the crypt (a buried carcass). The larvae hatch after a few days and move into a pit in the carcass which the parents have created. Although the larvae are able to feed themselves, both parents also feed the larvae by digesting the flesh and regurgitating liquid food for the larvae to feed on. This can speed up larval development.

Several pairs of beetles may cooperate to bury large carcasses and then raise their broods communally.

The adult beetles continue to protect the larvae, which take several days to mature. Many competitors make this task difficult, e.g. bluebottles and ants or burying beetles of either another or the same species.

The final-stage larvae migrate into the soil and pupate, transforming from small white larvae to fully formed adult beetles.

Parental care is quite rare among insects and burying beetles are remarkable exceptions.