Woodlouse | Pest ID Guide
Quick Facts About Woodlouse
Woodlice (plural for woodlouse) are small land-dwelling crustaceans that seek out damp environments and can invade homes in search of moisture. While not dangerous to humans, their presence often indicates excess moisture issues that could lead to structural problems.- Size: 1/4 to 1/2 inch long
- Color: Gray to brown
- Shape: Oval, segmented body with a hard shell-like exoskeleton
- Active Season: Year-round, more active in warm, humid conditions
- Lifespan: 2-3 years
- Reproduction Rate: Females produce 24-28 eggs per brood
What Do Woodlice Look Like?
Woodlice have segmented, armored bodies with seven pairs of jointed legs that allow them to move quickly across surfaces. Their most distinctive feature is the ability to roll into a tight ball when threatened, which has earned them nicknames like “pill bugs” or “roly-polies” in different regions. They have a shell-like exoskeleton that they molt regularly as they grow through distinct life stages.Key Identifying Features
- Segmented Body: Their bodies consist of distinct segments, giving them an armored appearance
- Seven Pairs of Legs: Like other crustaceans, woodlice have jointed appendages that help them navigate various terrain
- Antenna: Two prominent antennae at the front that help them sense their environment
- Rolling Defense: Many species can roll into a protective ball when threatened, distinguishing them from similar-looking pests
Related Species
Pill millipedes often resemble woodlice (particularly pill bugs) but have smoother bodies and more legs. Unlike woodlice, millipedes cannot roll into a perfect ball and move with a more flowing motion. Both species prefer similar habitats, though millipedes are more commonly found in garden environments rather than inside homes.
Health & Property Risks
Health Concerns
Woodlice do not bite, sting, or transmit diseases to humans or pets, making them one of the least harmful household pests.
- Allergies: In rare cases, their presence in large numbers may aggravate respiratory conditions due to their molted exoskeletons
- Psychological Discomfort: While harmless, many people find their appearance disturbing, causing stress when found in homes
- No Disease Transmission: Unlike many household pests, woodlice do not carry or transmit diseases
Property Damage
Woodlice rarely cause direct damage to homes, but their presence often indicates conditions that can lead to serious property issues.
- Indicator of Moisture Problems: Their presence suggests excessive moisture that could lead to wood rot and structural damage
- Garden Plants: In gardens, they may feed on young, tender plants and seedlings
- Secondary Infestations: Damp conditions that attract woodlice often attract more destructive pests like termites
Where to Look for Woodlice in Your Home
Woodlice require high humidity environments due to their need to prevent water loss. Look for them in basements, crawl spaces, under sinks with plumbing leaks, around foundations, and in bathrooms with poor ventilation. They’re often found beneath objects like rocks, flowerpots, mulch, and woodpiles adjacent to the home.When to Call Professional Help
Professional intervention becomes necessary when you consistently find woodlice inside your home, especially in areas that should be dry. This often indicates underlying moisture issues that need addressing. If you notice woodlice appearing after rainfall or in multiple areas of your home, it’s time to contact a pest professional who can not only address the infestation but also identify the moisture sources attracting them.
