Dung beetles belong to the superfamily Scarabaeoidea. Dung beetles have a diet which is partly or exclusively faeces.
There are dung-feeding beetles which belong to other families, such as the Geotrupidae (the earth-boring dung beetle).
The Scarabaeinae alone comprises more than 5,000 species.
Many dung beetles, known as rollers, are noted for rolling dung into spherical balls, which are used as a food source or brooding chambers. Other dung beetles, known as ‘tunnellers’, bury the dung wherever they find it. A third group, ‘the dwellers’, neither roll nor burrow, they simply live in manure.
The size of a dung beetle varies from species to species. The ‘dwellers’ are usually small and elongate. Dung beetles are basically black, brown or purplish yellow in color. Some are of metallic lustre, especially the tropical species. Most dung beetles have a flattened, but stout body.
The male of some species has horns at the head or thorax. Some dung beetles, other than the ‘dwellers’, have strong, often ‘toothed’ legs specialised for rolling dung and burrowing. The tarsi (claws) at the forelegs of an old dung beetle are usually damaged or lost owing to consistent burrowing – some species do not have tarsi at the forelegs at all. The desert species also have hair on the legs which helps their movement on sand. Dung beetles have soft mouthparts suited to their diet.
Dung beetles live in many different habitats, including desert, farmland, forest, and grasslands. They do not like extremely cold or dry weather. They occur on all continents except Antarctica.
Dung beetles eat dung excreted by herbivores and omnivores. Their preferred excretion comes from herbivores. Many of them also feed on mushrooms and decaying leaves and fruits. They do not need to eat or drink anything else because the dung provides all the necessary nutrients. The larvae feeds on the undigested plant fibre in the dung, while the adults do not eat solid food at all. Instead they use their mouthparts to squeeze and suck the juice from the manure.
Most dung beetles search for dung with the aid of their strong sense of smell. Some of the smaller species, however, simply attach themselves to the dung-providers to wait for their food. After capturing the dung, a dung beetle will roll it, following a straight line despite all obstacles. Sometimes dung beetles will try to steal the dung ball of another beetle, so the dung beetles have to move rapidly away from a dung pile once they have rolled their ball to prevent it from being stolen.
Dung beetles mate underground. After the mating, both or one of them will prepare the brooding ball of manure. When the ball is finished, the female lays eggs inside it. Some species do not leave after this stage, but remain to safeguard their offspring.
The dung beetle goes through a complete metamorphosis. The larvae live in brood balls made with dung prepared by their parents. During the larval stage the beetle feeds on the dung surrounding it.
Dung beetles play a remarkable role in agriculture. By burying and consuming dung, they improve nutrient cycling and soil structure. They also protect livestock, such as cattle, by removing the dung which, if left, could provide habitat for pests such as flies.