Decomposers are living things that break down dead plants and other leftovers, and people call them nature's clean-up crew. They recycle nutrients from dead plants back into the soil, which helps plants grow. A compost pile is one place to see them at work. There, tiny living things and small bugs eat old leaves and food scraps, and the result is dark brown compost.

Inside a working pile, tiny living things are eating, and their work makes the pile warm. The work goes in stages. Bacteria work first, and their numbers jump. When the pile cools, centipedes, millipedes, sowbugs and earthworms carry on the work. Millipedes are slow and eat rotting plants. They do not bite people or harm things in a home.

Termites are tiny insects that eat wood. They break down old, dead wood in the wild. Most of them cannot digest wood alone. Tiny one-celled living things called protists in their gut help turn wood into food for the colony. They eat the soft part of the wood grain first and leave the harder part. By breaking down fallen trees and stumps, termites help forests, because their nutrients go back into the soil.

Springtails are tiny and can jump. They live in wet soil, leaf litter and compost, where they eat fungi and rotting plants. They breathe through their skin, so they need damp places. A fork-like part is folded under the body. When it lets go, the fork flicks the springtail into the air. They cannot bite or sting, so they are harmless to people.

Leafcutter ants bring leaf bits to their nest instead of eating them. They chew the bits smaller, add them to a fungus garden and eat what grows there. Earthworms eat dead leaves and bits of soil too. The droppings they leave, called casts, hold soil, plant bits and tiny microbes, and they feed the soil.

Most body parts of a millipede have two pairs of legs, so it has many legs. It needs damp air and hides under leaves, logs and stones. It curls up when it is disturbed. Adult black soldier flies do not bite, and they live only about six days. Black soldier fly larvae feed on rotting food scraps and leave behind something good for soil.

Some beetles eat dung from animals and bury it in the ground. If dung beetles and other helpers are missing, a cow dung pile can stay in a field for a very long time and smother the grass. When dung is buried in soil, its nutrients are recycled back into the soil. Left on top, nutrients such as nitrogen can be lost or run off.

Words to know

• decomposers: leftover breakers
• bacteria: tiny living things
• protists: one-celled life
• nutrients: plant food
• casts: worm droppings

The short version

Decomposers are living things that break down dead plants and other leftovers, and they recycle nutrients back into the soil, which helps plants grow. Termites eat wood, springtails eat fungi and rotting plants, earthworms eat dead leaves, and some beetles bury animal dung in the ground.

Quick facts

• Decomposers recycle nutrients from dead plants back into the soil, which helps plants grow.
• In a compost pile, bacteria work first. When the pile cools, centipedes, millipedes, sowbugs and earthworms carry on.
• Most termites cannot digest wood alone. Protists in a termite's gut help turn wood into food for the colony.
• When dung is buried in soil, its nutrients are recycled back into the soil.