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October 2009 cover image lesser prairie-chicken

Wild Thing: Roly-Poly Pillbugs

Neither pill nor bug, these cuties are actually crustaceans.

By Sheryl Smith-Rogers

As a kid, you probably kept a cute little roly-poly (pillbug) as a pet. Now that you’re grown, the last thing you want to see is one tooling across your kitchen floor. Not cute. So out the door it goes! After all, bugs belong outside, right?

Sure. But before you administer the boot, consider this: Pillbugs are neither bugs nor insects. They’re terrestrial crustaceans known as isopods. Like shrimp and lobsters, pillbugs breathe through gills, only not underwater. However, since gills require water to function, pillbugs prefer damp habitats, such as under rocks, potted plants or leaf litter.

pill bug

Armadillidium vulgare — as its genus name suggests — resembles a tiny gray armadillo. Seven segmented plates form a pillbug’s hard exoskeleton and allow maximum flexibility. Thus, it can easily roll into a “pill” to escape predators. Sowbugs, another isopod, resemble pillbugs but are flatter, with two short posterior “tails.” Since they are unable to roll up like pillbugs, sowbugs run fast, instead.

Annoying but harmless, pillbugs can devour tender vegetation in the landscape and garden. These scavengers particularly relish decaying matter, including wood, mulch and lawn clippings. In the spring after mating, a female — who may reproduce two or three times a year — incubates up to 200 eggs in a brood pouch located underneath her body. After hatching, the tiny pillbugs stay in the pouch several more weeks, then venture out on their own. In a year, they’re adults.

Got a pet pillbug in the house? Then you’ll be happy to know that your cute little isopod can live as long as three years!

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