Pillbugs and Sowbugs
Pillbugs and sowbugs are terrestrial crustaceans, not insects, that are commonly found in moist environments under mulch, stones, logs, and leaf litter. Pillbugs roll into a tight ball when disturbed, earning the nickname roly-poly, while sowbugs cannot roll up and have two small tail-like appendages. Both require moisture to breathe through gill-like structures and will die from desiccation within a day or two indoors. They are among the most common occasional invaders of basements, garages, and ground-level entries.
Species in This Group (2)
Pill Bug
Armadillidium vulgare
The Pill Bug is a terrestrial crustacean (isopod) commonly found in moist garden environments.
Sow Bug
Porcellio laevis
The Sow Bug closely resembles the pill bug but is distinguished by its inability to roll into a ball and the presence of two tail-like uropods.
Key Behaviors
Pillbugs and sowbugs are nocturnal detritivores that feed on decaying organic matter in soil and mulch. They aggregate in large numbers under objects that retain moisture against the soil. They enter homes through foundation gaps, under doors, and around basement windows. They cannot survive indoors and die quickly from dehydration. Their presence in large numbers indicates excessive moisture and organic debris around the foundation.
Risks & Concerns
Pillbugs and sowbugs are completely harmless and do not bite, sting, or damage structures or belongings. They are strictly a nuisance when they enter homes in numbers. Occasional feeding on tender seedlings and strawberries in gardens is their only agricultural impact. Their presence indoors is a reliable indicator of moisture conditions that should be addressed for other pest prevention reasons.
Quick Comparison
| Species | Size | Color | Key Trait |
|---|---|---|---|
| Pill Bug | 8-18 mm | Slate gray to dark gray, sometimes with lighter edges on segments | Ability to roll into a tight, armored ball when disturbed; convex, segmented body; actually a crustacean, not an insect. |
| Sow Bug | 10-15 mm | Dark gray to brownish-gray with lighter edges | Similar to pill bug but CANNOT roll into a ball; has two small tail-like appendages (uropods) at the rear. |
Need Help With Pillbugs and sowbugs?
If you're seeing signs of pillbugs and sowbugs in or around your home, professional treatment is the fastest way to stop the problem. Lotus Pest Control offers free inspections to identify the issue and recommend the right solution.