Roly-poly bugs, also known as pill bugs or woodlice, are common backyard visitors. Despite their nickname, they are not insects; they are terrestrial crustaceans belonging to the order Isopoda, making them more closely related to shrimp and crabs. While generally beneficial to the environment, they are often found near or inside homes. Their presence is driven by three fundamental needs: moisture, decaying organic material for food, and dark, protected shelters.
The Critical Need for High Humidity
The most significant factor attracting these crustaceans is their requirement for a highly humid environment. Unlike insects, roly-poly bugs breathe through gill-like structures that must remain damp to function and extract oxygen from the air. Because they lack a waxy cuticle to conserve water, they are extremely susceptible to desiccation.
This physiological limitation means they must constantly seek out damp microclimates to survive. If they dry out, they will suffocate. They are most active during the night when humidity is highest. Both the classic pill bug and the closely related sow bug share this overriding need for moisture.
Preferred Diet and Feeding Habits
Roly-poly bugs are detritivores, feeding mainly on dead or decaying organic matter. This feeding habit makes them nature’s recyclers, breaking down materials like fallen leaves, rotting wood, and other plant debris. They play a role in soil health by returning nutrients back into the ecosystem.
Compost piles or thick layers of leaf litter act as powerful attractants by providing a consistent food supply. They also consume fungi, including mold, and animal feces. While their main diet is decaying material, they occasionally feed on tender new plant growth, such as young seedlings, especially when preferred food sources are scarce.
Ideal Physical Shelter Locations
Roly-poly bugs seek out physical locations that combine necessary moisture with dark, cool, protected areas. They hide in places that minimize water loss and shield them from the sun’s drying heat. These shelters often include areas where moisture is trapped or naturally accumulates.
Common locations include spaces underneath stones, bricks, and patio slabs, which retain coolness and moisture. Thick layers of organic mulch or dense ground cover plants also create an attractive habitat by insulating the soil and maintaining high humidity. Around the home, they are frequently found along foundation perimeters, especially where water from air conditioning units or leaky spigots keeps the soil constantly damp.
Reducing Roly Poly Presence
Managing roly-poly populations near or inside a home involves directly addressing moisture and shelter attractants. Homeowners should first focus on eliminating excess water sources near the foundation. This includes fixing leaky outdoor faucets and ensuring gutters drain water away from the house. Improving ventilation in damp areas like crawl spaces and basements helps lower the humidity levels these creatures require to survive.
Removing their preferred shelter and food sources is an effective management technique. This means raking up excessive leaf litter, grass clippings, and other organic debris from around the home’s perimeter. Stacking firewood off the ground and away from the foundation limits a major hiding spot. Reducing mulch depth to no more than two inches and pulling it back a few inches from the foundation creates a “dry zone” that discourages their presence.