Pill Bug or Roly-poly
Scientific Name: Armadillidium vulgare (most common species, but could be other Oniscidean isopods)
Order & Family: Isopoda, Armadillidiidae (for Armadillidium vulgare)
Size: Typically 0.5 to 1.5 cm (0.2 to 0.6 inches) in length.
Natural Habitat
Damp, dark places; under rocks, logs, leaf litter, decaying wood, garden debris. Often found in gardens, basements, and other moist environments.
Diet & Feeding
Detritivores, primarily feeding on decaying organic matter such as dead plants, fungi, and occasionally young seedlings or soft fruits. They play a role in decomposition.
Behavior Patterns
Nocturnal, most active at night. When disturbed, they roll into a tight ball (conglobation) to protect their vulnerable underside. They breathe through pseudotrachea, requiring a moist environment to do so. They undergo molting in two halves, first the posterior and then the anterior.
Risks & Benefits
Potential risks: Generally harmless to humans. Can occasionally damage young garden seedlings if other decaying matter is scarce, but this is usually minor. Benefits: They are beneficial decomposers, breaking down organic material and returning nutrients to the soil. They also help aerate the soil.
Identified on: 11/26/2025