Millipedes help the compost process by feeding on dead plant matter. Centipedes Centipedes are multi-segmented invertebrates, with each body segment having one pair of legs. Centipedes feed on other invertebrates of many sizes, therefore centipedes do not directly assist in decomposing the plant material in compost. However, centipedes are part of the compost community and can coexist with the decomposers. Spiders Spiders may be present in your compost, where they feed on invertebrates.
Spiders help control garden pests.
Earthworms Earthworms are gardener's dream workers because they perform many functions that produce excellent compost. Their primary activity is eating through organic matter, decomposing materials into rich castings that help the garden grow. Earthworms also move up and down in the soil and compost creating passageways for air and water. Furthermore, material that has passed through the earthworm, the castings, is higher in available nutrients. Hot temperature composting will kill earthworms.