Small orange centipedes are common members of the ecosystems in our compost heaps. Photo by Sarah Walker.

by Sarah Walker, from the July 2006 Newsletter

When I lift up an old board that’s been laying on the ground or investigate my compost heap, I spy a crowd of different shapes and colors that slither, run, walk or roll up in a ball. I am intruding upon the workforce of my yard: the invertebrates that live shred, chew and recycle my kitchen scraps and yard waste into lovely compost.

Without the decomposers, my yard would be waist deep in coffee grounds, orange rinds, dead leaves, branches and grass clippings. These critters in our yards are not “pests,” but contributing members of the dark and earthy ecosystem beneath our feet.

Suddenly, a bright orange, many-legged creature dashes past the undulating pink earthworms, roly-poly pillbugs and stately black beetles. It looks like a centipede, and indeed it is.

This one’s only 1 1/2” long—probably too small to deliver much of a bite to humans, says U of I Entomologist Ed Bechinski. In its own world, the centipede is a predator. It uses its long back legs to snare, its fangs to bite, and its poison glands to immobilize insects, spiders or other things smaller than them.

Mentioning centipedes causes people to ask, what’s a millipede? Both are invertebrates with many body segments and many legs that live in damp dark places. But millipedes are scavengers, not predators, and they pursue a diet of dead plant material.

Centipedes have long antennae, flattened bodies, and one pair of legs per segment. Their escape reaction is to run away, fast. When a millipede senses danger, it rolls up in a ball. Millipedes have short antennae, round bodies, and two pairs of legs per body segment.

How many legs can a centipede have? The minimum, for official centipede designation, is 15 pairs. Bigger species have dozens of pairs of legs. But the ones with the fewest legs are actually the fastest because they can run with their bodies held straight. Longer centipedes with more legs run with a snake-like twisting motion that slows them down. I saw one of these longer models in Hawaii , running across the bed—believe me, it was terrifying!

I couldn’t find out much about centipedes’ life cycles, but I do have this startling tidbit: when male and female centipedes meet, they touch antennae, then the male follows the female around. At some point he produces a small silk web where he leaves off a package of sperm for the female to pick up later and impregnate herself.

“House centipedes” live around here too. They dash across our walls, sometimes falling into bathtubs where they are discovered by sleepy humans in the morning. These look scary but are harmless; they hunt and eat flies and other insects around the house. House centipedes don’t look like the ones in the compost heap. They have much longer legs and antennae and aren’t shiny orange or rust colored.

A tiny white soil-dwelling invertebrate with 12 pairs of legs called a “garden centipede” is too small to be commonly noticed. With less than 15 pairs of legs, they are not centipedes but symphylans, and considered pests in greenhouses and gardens because they eat roots of vegetables and flowers.

When I see centipedes, insects and spiders—or sowbugs, slugs, lobsters, sea urchins, or clams, I am reminded of how complex the invertebrate world is, and how many different types there are among those creatures who live inside a hardened outer covering instead of around a row of bones down the middle of their backs.

Copyright: Copyright on articles, recipes and images are jointly held by the Moscow Food Co-op and the respective contributors, except were otherwise noted.

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