Pill Bug

About the Pill Bug

Not actually an insect but a terrestrial crustacean - more closely related to crabs and shrimp than to insects. They are the only crustaceans that have fully adapted to land. They roll into a ball when threatened (conglobation). They breathe through gill-like structures that must stay moist. They have blue blood due to hemocyanin, a copper-based oxygen carrier. They molt in two stages - first the back half, then the front - one of few animals that does this. They remove heavy metals from soil, making them useful bioindicators.