Pillbugs
Pill bugs, commonly known as "rollie pollies" or "woodlice," are small, grayish to brown, oval-shaped crustaceans that can curl into a ball when threatened. Although they are not insects, they are often mistaken for them. They typically inhabit damp areas outdoors, such as under rocks, logs, and decaying organic material. However, during rainy or cooler weather, pill bugs may invade homes, especially in basements, crawlspaces, and bathrooms, where moisture is prevalent. While they do not pose a direct health threat to humans or pets, they can become a nuisance when they enter the home in large numbers.
Behavior
Pillbugs are nocturnal and thrive in moist environments due to their gill-like structures, which require humidity for respiration. They are detritivores, feeding primarily on decaying organic matter, and play a crucial role in nutrient cycling within ecosystems.
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Active during the night; hide in damp areas during the day
Feed on decomposing plant material and occasionally tender plant tissues
Require high humidity to survive; breathe through gill-like structures
Exhibit conglobation as a defense mechanism against predators
Generally harmless to humans; do not bite or sting
Identification
Pillbugs (Armadillidium vulgare), commonly known as rollie pollies, are small, segmented terrestrial crustaceans. They are often mistaken for insects but are more closely related to shrimp and lobsters. Their most distinctive feature is their ability to roll into a tight ball. A defensive behavior known as conglobation.
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Oval-shaped, gray to dark brown exoskeleton
Approximately 10 mm (0.4 inches) in length
Seven pairs of legs (one per body segment)
Two pairs of antennae; the second pair is more prominent
Ability to roll into a ball when threatened
Nesting
While pillbugs do not construct traditional nests, they seek out humid, sheltered environments to live and reproduce. Females carry fertilized eggs in a brood pouch (marsupium) until they hatch, providing protection and moisture to the developing young.
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Commonly found under rocks, logs, mulch, and leaf litter
Prefer environments with high moisture and organic matter
Females produce 1–3 broods per year, each containing 100–200 eggs
Young remain in the marsupium for 1–2 weeks post-hatching
Molting occurs in two stages: posterior half first, then anterior
Impact
Pillbugs are generally beneficial due to their role in decomposing organic matter. However, in large numbers, they can become nuisance pests, especially when they venture indoors or feed on young plant seedlings.
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Contribute to soil health by breaking down organic debris
Occasionally feed on tender plant parts, affecting seedlings
May enter homes seeking moisture but typically do not survive indoors
Do not transmit diseases or cause structural damage
Presence indoors often indicates high outdoor populations