The pill bug (Armadillilium vulgare) is a small, segmented land creature that is covered by a hard exoskeleton shell that looks like armor. They have three basic body parts, the head, the thorax, and the abdomen. Pill bugs have 7 pairs of jointed legs and 2 pairs of antennae – but one pair is barely visible. The antennae, mouth and eyes are located on the head. Pill bugs are less than an inch long. Many animals eat pill bugs and the main protection for the pill bug is rolling into a tiny armored ball. They are also called the wood louse or the roly-poly bug, as they are known for this ability to roll into a ball.
Pill bugs are common invertebrates that are found in many biomes around the world, including temperate forests, rainforests, and grasslands. The pill bug is not an insect but is an isopod. They are more closely related to shrimp and crayfish than to insects and are the only crustacean that has adapted to living their entire life on land. They prefer moist areas, often living in soil and under decaying leaves, rocks, and dead logs. Pill bugs mostly eat decaying vegetable material like vegetables.
In their immediate vicinity, pill bugs are beneficial as they provide minimal soil improvement. Pill bugs form an important component of the larger decomposer fauna, along with earthworms, snails, and millipedes. All of these animals return organic matter to the soil where it is further digested by fungi, protozoans, and bacteria, hence making vital nutrients available to plants. Although they may occasionally feed on roots, pill bugs do minimal damage to live vegetation and should not be regarded as pests. They are also a food source for other animals. A pill bug begins its life as a tiny egg. The young pill bug looks almost like a miniature adult. As it grows, it molts (sheds its old, outgrown exoskeleton) 4 to 5 times.
This species lives where it is wet or moist and usually in a shaded area. They are found under damp objects or in organic garbage such as vegetable debris. Look under logs, moist leaf litter, outdoor pet dishes, and under paving bricks or stones. If pill bugs enter a building, they will often dry out and die. Most pill bugs live for up to two years.
Pill bugs are scavengers and typically feed on decaying organic matter such as plants and animals. They occasionally feed on young living plants but the damage inflicted is seldom significant. They are most active at night.
Pill bugs thrive only in areas of high moisture, and tend to remain hidden under objects during the day. Around buildings they are common under mulch, compost, boards, stones, flowerpots, and other items resting on damp ground. Another frequent hiding place is behind the grass edge adjoining sidewalks and foundations.
Pillbugs may leave their natural habitats at night, and crawl about over sidewalks, patios, and foundations. Common points of entry into buildings include door thresholds, especially at the base of sliding glass doors. They often invade crawl spaces, damp basements and first floors of houses at ground level. Frequent sightings of these pests indoors usually means that there are large numbers breeding on the outside, close to the foundation. Typically however, if pill bugs enter a structure, they will often dry out and die.
There are a few main strategies to removing pill bugs from your home including minimizing moisture, removing debris, and sealing pest entry points to your home. The most effective, long-term measure for reducing indoor entry of pill bugs is to minimize moisture and hiding places near the foundation. Keep your homes and the areas around your home clean and dry. Don’t allow water to accumulate near the foundation or in the crawl space. Divert water away from the foundation wall with properly functioning gutters, down spouts and splash blocks. Repair leaking faucets, water pipes and air conditioning units. Control humidity in crawl spaces and basements by providing adequate ventilation, sump pumps, and dehumidifiers as needed. Since pillbugs require moisture, they do not survive indoors for more than a few days unless there are very moist or damp conditions.
Pill bugs can also be avoided by eliminating food sources such as vegetable or plant debris. Remove leaves, grass clippings, heavy accumulations of mulch, boards, stones, boxes, and similar items laying on the ground near the foundation. Items that cannot be removed should be elevated off the ground. Remove heavy accumulations of mulch and leaf litter.
To prevent pill bugs from entering your home, seal cracks and openings in the outside foundation wall, and around the bottoms of doors and basement windows. Install tight-fitting door sweeps or thresholds at the base of all exterior entry doors, and apply caulk along the bottom outside edge and sides of door thresholds.
Insecticides are of little use in controlling these pests. Once inside, pill bugs soon die from a lack of moisture. Removal with a broom or vacuum is all that is needed. For large infestations, insecticides may help reduce inward migration of these and other pests when applied at common outdoor entry points, along the bottom of exterior doors, around crawl space entrances.
The pillbug is often considered a pest when it gains entry into a home. Although they sometimes enter in large numbers, they do not bite, sting, or transmit diseases, nor do they infest food, clothing or wood. They do not spread diseases or contaminate food and are a nuisance simply by their presence.