Question How are millipedes and centipedes alike and how do they differ?

Answer

While both millipedes and centipedes belong to the phylum Arthropoda and to the subphylum Myriapoda, millipedes belong to the class Diplopoda and centipedes belong to the class Chilopoda. Read on to discover additional ways in which millipedes and centipedes are alike or different.

Some of the ways in which millipedes and centipedes are alike include:

• They are both invertebrates (without backbones) and belong to the largest phylum in the Animal Kingdom which also includes insects, spiders, crabs, lobsters, etc.
• They both have one pair of antennae, many pairs of legs, and breathe through little holes or spiracles on the sides of their bodies.
• They both have segmented bodies, poor vision, external skeletons and jointed legs.
• They grow by moulting or shedding their external skeletons and, when young, grow new segments and legs each time they moult.
• They are both found throughout the world, but are most abundant in the tropics.
• They require a moist environment and are most active at night.

Some of the ways in which millipedes and centipedes differ from each other include:

• Millipedes have two pairs of short legs on each body segment, a rounded body, and a hard external skeleton. Their legs are tucked under the body and difficult to see. The number of body segments varies with the species (estimated in the range of 10,000 species), but the number of pairs of legs generally ranges between 40 and 400. The females of a nearly extinct species of California millipede have up to 750 legs.
• Centipedes have only one pair of legs on each body segment; these are easily spotted sticking out from their flattened bodies. The number of body segments varies with the species (estimated in the range of 8,000 species), and the pairs of legs vary from 15-177, plus or minus one. Centipedes have an odd number of pairs of legs; the last pair trails behind the body.
• Millipedes have short antennae and move in slow waves, burrowing and eating their way through moist leaf clutter, fungi, and decayed plant material on the ground. As they plow through the soil, munching on dead plants and other vegetation, they aerate and enrich the soil, much like earthworms.
• Centipedes have long antennae and their back legs are nearly as long as their antennae. The antennae help them locate their prey, and their first pair of legs, modified into venomous claws, help them capture and paralyze their prey. Centipedes eat spiders, insects, worms, and other arthropods. The Amazonian giant centipede is over twelve inches in length and is said to eat frogs, mice, and lizards.

• Millipedes are attacked by shrews, toads, birds, and badgers. When attacked, millipedes curl their bodies into tight spirals to protect their soft undersides. This coil shape also protects their heads and legs. They sometimes burrow to bury themselves when disturbed, using their front legs to push away the soil. Many species of millipedes have defense glands (called ozopores) which discharge a smelly and disgusting-tasting liquid that drives off many predators. This liquid contains a variety of irritants including hydrochloric acid, phenol, and irritating quinones.
• Centipedes are attacked by lizards, scorpions, and birds. Centipedes are flexible, fast, and toxic. They use both their long back legs and antennae in escaping predators, speedily scuttling away between cracks in rocks, litter, and logs. Centipedes can quickly move backwards and sideways if necessary. In addition to poisoning animals with their venomous bite, centipedes can use their long back legs to squeeze a predator. Their venom includes several substances including histamines, serotonin, and cardio-toxins. Centipedes can also, like some insects, crabs, and lobsters, simply “drop” legs held by a predator and run away on their remaining legs.

Published: 11/19/2019. Author: Science Reference Section, Library of Congress