Millipedes are often confused with centipedes but their mobility gives the vital clue. Millipedes (pictured) clear up dead plants and animals and recycle the nutrients, and they curl up when disturbed. Centipedes are hunters and move very fast. They both love damp places and are found under logs and stones and in the compost heap. Occasionally millipedes nibble roots of seedlings but are rarely serious pests. There are more than 10,000 species.