If you’ve ever lifted a damp paving stone or a flowerpot in your garden, you’ve likely seen them: small, grey, armored bugs that scurry for cover. Many people call them “roly-polies,” but did you know there are actually two different common types? They are sow bugs and pill bugs.
While they look incredibly similar, there is one simple, foolproof way to tell them apart: A pill bug can roll into a tight, perfect ball, while a sow bug cannot.
The “Roll Test” and Other Key Differences
Let’s break down the distinct features of these two common garden dwellers.
The Pill Bug (Armadillidiidae)
- Defense Mechanism: Its defining feature. When threatened, the pill bug’s segmented plates allow it to tuck its head and legs in and form a perfect sphere, protecting its soft underside. This is why it earned the “roly-poly” nickname.
- Appearance: It has a more dome-shaped, convex body, which is what allows it to roll up so effectively. It does not have any visible tail-like appendages.
The Sow Bug (Porcellionidae)
- Defense Mechanism: A sow bug cannot roll into a ball. Its body is flatter and its plates are less flexible. When threatened, it will either flee or hunker down flat against the ground.
- Appearance: It has a flatter, more oval-shaped body. The most obvious visual clue (besides not rolling up) is a pair of two small, tail-like appendages called uropods sticking out from its rear end.
Here’s a quick comparison:
| Feature | Pill Bug (“Roly-Poly”) | Sow Bug |
| Rolls into a Ball? | Yes, a perfect sphere. | No. |
| Body Shape | More dome-shaped | Flatter and more oval |
| “Tail” Appendages? | No | Yes, two small ones |
| Primary Defense | Rolling into a ball | Fleeing or staying flat |
Are They Harmful Pests?
Here’s the good news: neither sow bugs nor pill bugs are harmful.
- They are not insects, but terrestrial crustaceans, more closely related to crabs and shrimp.
- They don’t bite, sting, or carry diseases.
- They don’t damage sound wood or the structural parts of your home.
- They are beneficial decomposers in the garden, helping to break down decaying organic matter.
So, why are they inside your house? Their presence indoors is almost always a sign of a significant moisture problem. They need high humidity to survive and are drawn to damp basements, crawl spaces, or areas with leaks.
What to Do If You Have an Infestation
Finding a few of these critters is normal, but finding a lot of them inside means you should address the underlying issue.
- Control Moisture: Use a dehumidifier in damp areas like basements. Fix any plumbing leaks or drainage issues.
- Seal Entry Points: Close up cracks in your foundation and add weatherstripping to doors to block their entry.
- Clear Debris: Move woodpiles, leaf litter, and thick mulch away from your home’s foundation.
If you are dealing with a large number of these pests in your Dhaka home and are worried about the moisture that’s attracting them, it’s time for a professional opinion. Contact the experts at Carepestcontrolbd.com to identify the source of the problem and implement a pest control strategy that keeps your home dry and pest-free.