Dung beetles fall into groups by what they do with dung: dwellers live and breed in the dung, tunnellers drag it underground, rollers shape it into balls and roll it away, and stealers take the brood balls other beetles made. Tunnelling dung beetles drag dung underground and lay their eggs in brood balls made from the dung. When dung is buried in soil, its nutrients are recycled back into the soil. When dung is left on top, nutrients such as nitrogen can be lost or run off. North America north of Mexico has about 170 species of dung beetle, and Vermont and New York surveys found 24 species on dairy, beef and grazing farms (as of April 2026).

Without dung beetles and other helpers, a pile of cow dung can sit in a field for a very long time and smother the grass under it. South Dakota researchers tested dung beetles by caging some dung pats to keep insects out and leaving others open. Caged pats broke down much more slowly, so the insects were doing real work. Dung pats that the whole community of insects could use broke down about 30 percent more than pats kept from them. In a South Dakota pasture study, fresh dung pats lost about 28 percent of their wet weight in the first two days, probably because dung beetles arrive early. They feed on the liquid part, then leave tunnels and eggs, and their larvae eat the drier fibers.

There are on average 100 to 500 earthworms in each square meter of soil, and worms make up a large share of the weight of soil animals. Earthworms come in three kinds by where they live: surface worms in leaf litter, topsoil worms that tunnel sideways, and deep-tunnelling nightcrawlers that pull leaves down into the soil. The common nightcrawler came from Europe and is not native to the United States. In undisturbed soil, earthworms raise the rate at which rain soaks in, and their tunnels are lined with castings that act like fertilizer for crop roots. U.S. Department of Agriculture scientists found more earthworms in fields that were tilled less. Earthworms ate crop leftovers and mixed them with soil, so worm casts were used as a way to check soil health.

Pill bugs and millipedes mostly eat rotting plants, but millipedes can sometimes nibble live roots. Millipedes live in damp places under old leaves and eat bits of rotting leaves, and they need damp air. Millipedes can matter more than microbes for leaf breakdown. In one study cited by Forest Service scientists, millipede density explained 40 percent of the variation in leaf decomposition rates, while microbial biomass explained only 19 percent. Millipedes are slow and do not bite people or harm things in a home. Burying beetles raise their young in an unusual way for insects: parents bury the body of a small animal as food for the larvae before egg-laying, and after the larvae hatch both parents feed them.

Termites help recycle carbon. They thrive on tough materials such as wood and soil, and entomologists say they play important roles in global carbon recycling, though they also damage wooden buildings. Termites help forests by breaking down fallen trees and stumps and letting their nutrients go back into the soil. Termites are both pests and helpers: in houses they eat wood that people want to keep, but in nature they turn dead wood into nutrients for other living things. A termite colony has workers, soldiers, and kings and queens (the reproductives), and queens lay the eggs. Worker termites find and eat the wood, and termites eat the soft part of the wood grain first and leave the harder part.

Black soldier fly larvae eat rotting food scraps. They turn waste into frass, their droppings and leftovers. Farmers can use frass as a soil booster, and they can feed the larvae to chickens and fish. About 1 gram of their eggs can process up to 5 kilograms of food waste, but the amount depends on conditions, how many larvae there are, and what the waste is. About 40 percent of food made for people in the United States never gets eaten, and black soldier fly larvae are one way to turn some of that waste into soil booster and animal feed (as of January 2025). Adult black soldier flies do not bite, and they live only about six days.

Some beetles eat animal dung, which is poop, and bury it in the ground, and dung beetles can also help hold down pest flies in livestock pastures. Their work makes dung pats less welcoming to fly eggs and maggots, so cattle farmers may keep dung in a state that dung-using insects like. Dung beetle numbers are falling around the world (as of April 2026). Causes include loss of pasture, fewer farms that graze animals, habitat breaking into pieces, and pesticides and fertilizers, and some animal medicines pass out in dung and are particularly toxic to dung beetles. Some countries, such as Australia and New Zealand, release dung beetles on purpose to help clear livestock dung from pastures (as of April 2026).

Words to know

• tunnellers: tunnel diggers
• brood: young raised together
• castings: worm droppings
• frass: larvae droppings
• decomposition: breaking down