When a multi-legged creature scurries across your floor or garden path, it often triggers a mix of curiosity and alarm. Many refer to these elongated arthropods as “centipede-looking bugs.” This article clarifies their identities, helping you distinguish between them and understand their roles in your home and garden.
Distinguishing Centipedes, Millipedes, and Other Look-Alikes
Distinguishing between centipedes, millipedes, and other similar invertebrates involves observing key physical characteristics. Centipedes possess a flattened body with a single pair of legs per segment, giving them a wide stance. Their legs are often long and extend outward, allowing for quick, agile movement. They have whip-like antennae at the front and modified legs at the rear that resemble antennae, making it hard to tell their front from their back.
In contrast, millipedes have a rounded, cylindrical body shape, with two pairs of legs per segment. Their shorter legs are positioned directly beneath their bodies, leading to a slower, wave-like motion. Silverfish, a common household inhabitant, have a carrot-shaped body covered in silvery scales, three long, tail-like appendages at their rear, and six legs near the front.
Common “Centipede-Like” Household and Garden Inhabitants
Certain multi-legged arthropods are frequently encountered in and around human dwellings. The house centipede, Scutigera coleoptrata, is common indoors, particularly in damp areas like basements, bathrooms, and crawl spaces. This yellowish-gray species has up to 15 pairs of unusually long legs, giving it a distinct appearance as it darts across surfaces. House centipedes are nocturnal hunters, relying on sensitive antennae to locate prey such as cockroaches, silverfish, and spiders.
Garden centipedes are smaller and found outdoors under stones, logs, or leaf litter, favoring moist habitats. These centipedes are predatory, feeding on soil-dwelling insects, larvae, and soft-bodied invertebrates. Their presence in a garden indicates a healthy ecosystem, as they contribute to natural pest control.
Common millipede species, such as garden millipedes, are found in gardens and occasionally indoors. Millipedes prefer damp environments, thriving in leaf litter, decaying wood, and compost piles. They consume decaying plant matter, breaking down organic material and enriching the soil. Millipedes sometimes wander into homes seeking moisture or shelter, but they do not survive long in dry indoor conditions.
Are These Bugs Harmful or Helpful?
The impact of these multi-legged creatures varies by species. Centipedes are generally considered beneficial due to their predatory nature. House centipedes, for instance, prey on common household pests like cockroaches, silverfish, and spiders, acting as natural pest controllers.
All centipedes are venomous, but their venom is primarily for subduing prey and is not dangerous to humans. A house centipede bite is rare and results in mild, localized pain and swelling, often compared to a bee sting. Larger centipede species can inflict a more painful bite, but serious reactions are uncommon.
Millipedes, in contrast, do not bite and are not venomous. They are primarily decomposers, feeding on decaying organic matter and contributing to soil health by breaking down plant material and cycling nutrients. When threatened, some millipede species can exude a defensive liquid that may irritate skin or eyes, but they pose no significant threat to humans. In large numbers, millipedes might occasionally feed on sprouting seeds or ripening fruits if decaying matter is scarce.
Strategies for Coexistence or Management
For those who prefer to manage their presence, several strategies can help. Since both centipedes and millipedes are attracted to moisture, reducing humidity is an effective first step. Using dehumidifiers in damp areas like basements and ensuring good ventilation in bathrooms can make your home less appealing. Repairing leaky plumbing and addressing standing water sources also helps eliminate attractive habitats.
Preventing entry is another key management strategy. Sealing cracks and gaps in foundations, around windows, and under doors blocks their access into your home. Removing outdoor clutter such as leaf litter, woodpiles, and thick mulch near the foundation reduces hiding spots and food sources. For house centipedes, controlling populations of their prey, like other household pests, naturally reduces their presence. Natural deterrents such as diatomaceous earth, which dehydrates insects, or essential oils like peppermint and eucalyptus, which repel them, can also be used around entry points or in damp areas.