Pillbug

Armadillidium vulgare, commonly known as the pillbug, sowbug, or roly-poly, is a terrestrial isopod belonging to the suborder Oniscidea within the order Isopoda. Adults typically measure 10–18 mm in length, displaying a distinctive segmented, convex, slate-gray dorsal exoskeleton (telson and uropods are retracted, unlike Porcellionidae). Their lifecycle involves hemimetabolous development, with females brooding eggs in a specialized ventral pouch called a marsupium for 3–7 weeks, producing 20–200 mancae per clutch. These mancae molt through multiple instars over several months to a year, reaching sexual maturity within a year and living for up to three years, requiring high humidity (70-90% RH) for survival.

Pillbugs are primarily nocturnal detritivores, emerging after dusk to forage on decaying organic matter, fungi, and sometimes tender plant tissues like seedlings or overripe fruits. Communication is largely tactile and chemosensory, particularly concerning mating and aggregation in moist microhabitats. They exhibit pronounced conglobation—rolling into a tight, nearly spherical ball—as a primary defense mechanism against predators and desiccation. While generally harmless, large indoor incursions during extreme weather, particularly heavy rains or prolonged drought, can lead to their presence in living spaces, though they pose no public health risk and do not sting or bite, typically dying from desiccation within days indoors.