Countless feet

You rarely see them, unless you go poking about under rotten logs, but millipedes are very important creatures. They can damage plant roots sometimes but generally they are nature’s tidy uppers. The technical term is detritovores, they feed on detritus or dead materials in the environment from fallen leaves to fallen trees where the wood has begun breaking down with fungus, helping to recycle nutrients.

Millipedes are members of the Myriapoda, literally creatures with ‘countless feet’ although most people talk about the legs, but the ‘milli’ means a thousand, neither is correct scientifically. Most UK millipedes have between 60 and 400 legs, and myriapodologists (yes that is a word) tell similar species apart by counting the legs. The only millipede with a thousand legs is an Australian one called Eumillipes, literally ‘true thousand’. One specimen had 1,306 legs, yes someone counted them.

Millipedes are different to the other Myriapod group the centipedes, literally ‘100 feet’ but they the common centipede has 15 pairs. The notable difference is that millipedes have two pairs of legs on most segments while centipedes have only one pair per segment. The key difference is that centipedes are carnivores, they have to run quickly to catch their prey. A millipede trying to run fast would probably gets its legs tangled.

Watching a millipede glide along is fascinating, the leg movements appear as a wave moving from the back towards the head. They are not built for speed, but having so many legs allows the millipede to exert considerable force for its size as it pushes through the material such as soil and rotten wood.

There are some pill millipedes that can roll into a ball like a woodlouse, but the most common are either flat backed which look rather like centipedes, and the barrel species sometimes called snake millipedes. The barrel millipedes usually have the most segments and this allows them the flexibility to roll into a coil for protection. They can also produce a foul smelling and poisonous chemical cocktail including cyanide if they are threatened. Living as they do in the dark, millipedes have very poor eyesight, the spotted snake millipedes have no eyes at all.

The commonest flat backed millipede is Polydesmus which is usually found in deep leaf litter which is its preferred food. The flattened shape is ideal for easing between the compacted layers of rotting leaves.

Two common barrel species are the black snake millipede which has white legs, and the spotted snake millipede which is pale with red spots along the side. The spots are the poison glands. Spotted snakes can be a pest eating into the roots of vegetable crops, but overall these fascinating creatures should be welcome for the good they do.

Ed Dolphin