A woodlouse is a crustacean
Most of the creepy-crawlies in this grid are not insects at all. The WOODLOUSE is a crustacean, a land-living relative of crabs, shrimps and lobsters. It still breathes through gill-like structures on its underside, so it must stay somewhere damp, under logs and stones, or dry out and die. It eats rotting wood and leaves, helping turn dead plants back into soil.
The PILLBUG is the kind of woodlouse that can roll into a tight ball when threatened. Many common British woodlice cannot do it. The woodlouse has more local nicknames than almost any other small creature in Britain, from cheeselog to chuggy pig, depending on where you grew up. A SPRINGTAIL, a tiny creature found in almost every patch of soil, flicks itself into the air with a forked tail tucked underneath its body.
No centipede has a hundred legs
A CENTIPEDE has one pair of legs on each body segment, and every species has an odd number of pairs — so none has exactly one hundred legs. Centipedes are fast hunters with venomous claws just behind the head. The largest, the Amazonian giant centipede, can grow to around thirty centimetres and has been filmed catching bats hanging from cave ceilings. A MILLIPEDE has two pairs of legs on most segments, moves slowly, and eats rotting plants rather than other animals.
For a long time no millipede was known with anything like a thousand legs. In 2021 scientists described one found deep underground in Western Australia with 1,306, the first to earn the name properly. The HARVESTMAN, with its small round body and very long legs, is not a spider: it has one body section instead of two, no silk and no venom.
Darwin's last book was about worms
Charles Darwin spent decades studying the EARTHWORM, and his final book, published in 1881, was about how worms turn and enrich the soil. He tested whether they could hear by playing a piano and a bassoon to them, and found they could not, though they did react to vibrations. Earthworms pull leaves down into their burrows and slowly bury stones and even old buildings under the soil they bring up.
A worm has no lungs and breathes through its moist skin. It has five pairs of simple hearts. The GLOWWORM, despite its name, is a beetle: the flightless female glows on summer nights to attract a flying male.
Useful, if not lovely
The MAGGOT, the larva of a fly, is used in hospitals. Specially raised, sterile maggots are placed on wounds that will not heal, where they eat dead tissue and leave healthy tissue alone, and the treatment is available on the NHS. A LARVA is the young stage of many insects, and a NYMPH is a young insect that looks like a small adult, as in grasshoppers and dragonflies.
A TICK can pass on diseases, so it is sensible to check skin after walks in long grass, and a MITE is often too small to see. The rest of the grid holds the TARANTULA and SCORPION, the SNAIL and SLUG, the COCKROACH, the BEDBUG and the GRUB. Our spiders and snails and slugs pages go further into two of them.