Roly-poly, pill bug, doodlebug, or sowbug, whatever you call them, the more you know about them, the weirder they get!
First, they are not really bugs. They are crustaceans known as woodlice. Our garden species of woodlice are in the Armadillidium genus, along with armadillos, and they can roll up into a ball. Most woodlice cannot do this.
Even stranger than being related to armadillos, female woodlice carry fertilized eggs in a marsupial pouch, like a kangaroo! They can also reproduce asexually. If that weren’t enough, they breath through trachea-like lungs in their feet!
Woodlice prefer cool, dark, moist places - under planters, bricks, hoses, dense vegetation, whatever they can find. Having evolved from sea-going crustaceans, such as lobster and crab, water is critical to their survival. [Note: don’t eat them. Wikipedia says they taste like “strong urine”. I don’t know how they found out and I am certainly not going to try it myself!]
Dead plant material is a woodlouse’s favorite food. This makes them very helpful in compost piles and soil aeration. They also eat stinkbug eggs! Unfortunately, they will also eat ripe strawberries, Napa cabbage. and tender seedlings. The best way to take advantage of the benefits, without the risks, is to keep mulch and other dead plant material away from seedlings, until they are large enough to survive being gnawed by a woodlouse.
You can grow a surprising amount of food in your own yard. Ask me how!