Is the dung beetle a beneficial insect or a pest? Unveiling nature's scavenger

The dung beetle, also known as the dung chafer, with the scientific name Scarabaeus (dung beetle), has a certain phototaxis and can roll dung into a ball shape, pushing it forward. It mainly feeds on animal dung and has the title of “nature's scavenger”. So is the dung beetle a beneficial insect or a pest? According to agricultural scholar Li Changfei, the dung beetle uses its shovel-shaped head and oar-shaped antennae to roll dung into a ball, which can sometimes be as big as an apple. In early summer, the dung beetle buries itself and the dung ball in an underground earthen chamber and feeds on it. Later, the female lays eggs in the dung ball, and the hatched larvae also feed on it. The body is generally round in shape, with short elytra and the end of the abdomen exposed.

The male has a long, curved horn-like protrusion on top of its head. In 24 hours, it can eat food exceeding its own body weight. Because it can accelerate the process of converting dung into substances usable by other organisms, it is beneficial to humans. In addition, the dung beetle can clean up animal dung, suppress other pests that feed on dung, and reduce greenhouse gas emissions. In Australia, the original dung beetle species only liked to eat small-particle dung such as kangaroo dung, and did not like the dung of introduced cattle and sheep. From 1965 to 1985, under the leadership of a certain doctor, the Commonwealth Scientific and Industrial Research Organisation of Australia began the Australian Dung Beetle Project, successfully introducing 23 species of dung beetles from around the world, which improved the problem of dung accumulation on Australian pastures and at the same time reduced harmful bush flies by about 90%.

Appendix: The breeding patterns and feeding patterns of the dung beetle

1. Breeding patterns

Female dung beetles in the breeding period will make the dung ball into a pear shape and lay eggs inside it. The hatched larvae feed on the ready-made dung ball until they develop into adult dung beetles and emerge from the soil. Plant-eating dung beetles feed on sweet tree sap. After the male and female mate, the female dung beetle lays eggs in leaf mold soil. After about 10 days, the larvae break out of the eggs and feed on leaf mold soil or animal dung. The larvae grow continuously, pupate in July of the following year, and become adults after about 20 days. Dung beetles belong to the class Insecta and the order Coleoptera. The body is black or dark brown, with a hard exoskeleton on the body surface, well-developed compound eyes, chewing mouthparts, gill-like antennae, 3 pairs of legs suitable for digging, and 2 pairs of wings with the forewings hardened. Their mode of development is complete metamorphosis.

2. Feeding patterns

On the African savanna, on the night of the fourth day after the rains in the rainy season, thousands upon thousands of dung beetles emerge from the ground.

After the heavy rain, elephants greedily enjoy the newly grown plants, but their digestive systems find it hard to bear this suddenly increased load, and quite a lot of the swallowed food is returned to the ground. The giant dung beetle is the largest species among dung beetles, and its food source mainly depends on elephant dung.

Every day, the elephants leave hundreds of tons of elephant dung on the plains, followed by an army of dung beetles. Part of the elephant dung is buried underground, and the labor of the dung beetles makes the soil fertile. This is a cyclical process, in which the giant dung beetle plays an important role.

Appendix 2: How dung was handled in ancient times

In ancient times, there were no flush toilets, and the most basic way for people to handle the physiological need to excrete was to dig a pit in the ground and bury it after finishing. In agricultural society, because dung could be used as fertilizer, in cities a special person would collect the dung that each household had put in wooden buckets every night (commonly known as “night fragrance”). But in industrial society, with chemical fertilizers, as well as the hygiene problems of human excrement, people's impression of dung was greatly diminished. But in the past forty years, with the rise of the environmental protection movement, organic food produced from buried fertilizer made by fermenting poultry and livestock dung and other materials has again become popular in society. In ancient times, people called defecation “chugong”.