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NO. 048Common pillbug / roly-poly illustrationIllustration · not shown at life size

Other arthropods / Crustacean

Common pillbug / roly-poly

Armadillidium vulgare

AdultAn everyday search

A roly-poly is a crustacean, not an insect! Its hard plates fold into a ball.

A crustacean, and part of our tiny-neighbor collection.

Let’s look closer

Little clues

Three things to notice.

  1. Adults have seven pairs of legs.

  2. Rolls into a ball.

  3. Eats decaying plant material.

Out in the world

Where to look.

Around southeastern Wisconsin

Beneath damp pots and logs.

When to look

Look under damp cover by day. These small crustaceans often wander at night.

Gently lift a fallen leaf or pot with a grownup. Put it back as you found it.

A closer look

One clue is just the start.

A pillbug can curl into a ball. Many similar-looking sowbugs cannot close up that way. Both are crustaceans.

A special find can be hard to spot without being biologically rare. Encounters depend on season and habitat.

For curious grownups, too

Read a little further.

Original summaries, with references for deeper reading.