By Casey Smith, Naturalist
For many of us, the first “bug” we hold in our hands as children is what some call the roly-poly. We flip over logs on adventures in our own yards or parks, on elementary school field trips, or during summer camps. These unintimidating little critters seem harmless enough to hold in our hands, rolled into a ball for their own defense. But if we’re patient and quiet, they come out and explore the little hand now holding them. But do you know the actual name of these roly-poly bugs?
In Ohio, we have the common pill woodlouse (Armadillidium vulgare), often called a pillbug. But they’re not actually bugs. They are a terrestrial crustacean, also known as an isopod, and are most closely related to crabs, lobsters, crayfish, and shrimp, which are all related to insects and arachnids under the Phylum Arthropoda. If we break down the scientific name, Armadillidium refers to the way in which they can curl up into a ball, and vulgare means common. This ability to roll into a ball gives it its pill-like appearance, and the name pillbug. Pillbugs are nocturnal though they can be found during the day by flipping over rocks or logs. While they do feed on living plants, they are important decomposers, munching on decaying or decomposed plant matter, helping to return vital nutrients to the soil. They themselves are food for birds, some reptiles and amphibians, and some insects and arachnids. Though they are completely terrestrial, pillbugs breathe with gills, so it is important for them to be in humid environments. Females carry the eggs in a brood pouch on their bellies, and the young may stay in the pouch for an additional two weeks, surviving on nutrients received through marsupial fluid.
These amazing little critters are the only crustacean that has adapted to living completely on land. They breathe with gills, carry their babies in a pouch, curl up for defense, and make our soil healthier just by eating. So, roly-poly, woodlouse, pillbug, whatever you call them, take a closer look the next time you find one of these cool crustaceans.
Check out this video on pillbugs. https://youtu.be/sj8pFX9SOXE
