EPOW Ecology Picture of the Week -- A "Flat-back Tractor" in the Jungle

Explanation: No, this isn't a university experiment in small mobile robots. This is a "polydesmid" millipede that we found in the middle of the Congo River Basin in central tropical Africa.

Polydesmid millipedes can be found thoughout much of the world, but this one was a monster, stretching at least 8 inches (20 cm) long. These are quick, too, and rapidly scampered across the floor, on its 50 or so legs (no, a millipede does not have a thousand legs...).

Polydesmids are the most common order of millipedes. They have flattened bodies. Their eyes or greatly reduced or totally absent, so they rely on their antennae for sensory input.

The order name Polydesmida is Greek meaning many bands, which refers to some of the body segments being fused so that there are two pairs of legs per segment. Their bodies have a total of 18-22 segments; the one we caught here seems to have 18 or 19. The first and last segments are legless, segments 2-4 each have one pair of legs, and the rest of the segments have two pairs.

The fusion of many body segments lends structural strength for burrowing. When it burrows, it tucks its head under and forces through soil using the hardened cuticle plate behind the head.

Quite an amazing and complicated mechanism to coordinate! The name "flat-back tractor" seems to fit very well as it locomotes along.

They feed mostly on plants, particularly rotting vegetation. In so doing, they contribute important ecological functions to the formation of soil. Most millipedes are harmless to pick up. They do not bite and often curl into a defensive ball. However, many exude toxic substances including hydrogen cyanide from pores along the body. So wash your hands and follow health guidelines afterwards! And do not confuse a centipede -- which can bite -- with a millipede!

EPOW - Ecology Picture of the Week