Pill Bug (also known as Roly Poly, Pill Woodlouse)
Scientific Name: Armadillidium vulgare (this is the most common species of pill bug, though other species exist)
Order & Family: Order: Isopoda (within the class Malacostraca, which includes crustaceans like crabs and lobsters); Family: Armadillidiidae (for pill bugs specifically, as not all woodlice can roll into a ball).
Size: Typically 6 to 18 mm (0.24 to 0.71 inches) in length.
Natural Habitat
Damp, dark environments such as under rocks, logs, leaf litter, decaying wood, garden pots, and in soil. They are terrestrial crustaceans, but they require moisture to survive.
Diet & Feeding
Detritivorous; they primarily feed on decaying plant matter, fungi, and sometimes animal remains. They can occasionally nibble on young plants if other food sources are scarce.
Behavior Patterns
Woodlice are primarily nocturnal and prefer dark, damp environments. They are known for their 'conglobation' behavior, where they roll into a ball (like the pill bug shown) for protection when disturbed, mimicking seeds or pebbles. They are detritivores, playing an important role in decomposition. They breathe through pseudotracheae (or 'lung-like structures') on their pleopods and require moist air.
Risks & Benefits
Benefits: They are beneficial decomposers, helping to break down organic matter and enrich soil. This contributes to nutrient cycling in ecosystems. Risks: Generally harmless to humans, they do not bite or sting and are not known to transmit diseases. In gardens, large populations can sometimes damage seedlings or soft fruits, but this is usually minor and rare.
Identified on: 6/30/2025