Common Names: House centipede / Stone centipede
Scientific Names: Scutigera coleptrata / Lithobius forficatus
Centipedes are sometimes called hundred-leggers because of their many pairs of legs. Even though centipedes are predaceous and therefore beneficial, most customers consider them a nuisance pest. Some species can inflict a painful bite, but it is not lethal. They are widely distributed throughout most of the United States and the world.
American centipedes widely range from 1/8 inch to 6 inches in length. They are wormlike and are usually yellowish to dark brown in color, sometimes with darker stripes or markings. Most body segments bear 1 pair of similar legs, except for the 1st pair behind the head, which are modified into claw-like poison jaws and the last 2 pairs, which are directed backward and maybe elongated or pincer-like. Adult centipedes have from 15 to 177 pairs of legs, with 1 pair per segment. Centipedes have 1 pair of antennae consisting of 14 to 50 segments each, depending on the species. Some centipedes have compound eyes, but most have a cluster of simple eyes (ocelli) on each side of the head, or no eyes. First instar (hatchling) centipedes usually have 4 pairs of legs. Additional segments and pairs of legs are added with additional molts.
(1) Millipedes (Class Diplopoda) are usually cylindrical or have a slightly flattened body. Most body segments have 2 pairs of short legs, short antennae and are vegetarians and detritivores (feed on decaying vegetation). (2) Pillbugs and sowbugs (Order Isopoda) have 7 pairs of legs and have food preferences similar to millipedes.
The usual pest species seen indoors is the common house centipede Scutigera coleoptrata. The adult measures 1 to 1 1/2 inches long. Its body is grayish yellow with 3 dorsal longitudinal dark stripes. The antennae and last pair of legs are longer than its body. It has 15 pairs of long legs. The first instar (hatchling) has 4 pairs of legs and more legs are added through the next 5 molts (5, 7, 9, 11, and 13 pairs respectively). Then there are 4 additional pre-adult instars (developmental stages) before adulthood, each with 15 pairs of legs.
The stone centipede, Lithobius forficatus, measures about 1 to 1 1/2 inches long as adults and are glossy brick-red in color. The 15 pairs of legs are shorter than those of the house centipede.
Centipedes typically overwinter outdoors in protected situations and lay their eggs, usually in or on the soil, during the summer. Females of the house centipede Scutigera have been observed to produce 35 eggs aver a period of days. The common house centipede may live for more than a year; other species may live as long as 5 to 6 years.
All centipedes have poison jaws with which they inject venom to kill or stun their prey. If handled roughly, some of the larger species can break the skin (of humans), resulting in a bite which causes some pain and swelling, similar to that caused by a bee sting.
Centipedes are typically found in areas of high moisture such as beneath loose bark, in rotting logs, under stones, under porches, patios and decks, in wood and stone landscaping borders, under piles of leaves, grass clippings and mulch, where their prey is found. They enter homes beneath siding, along thresholds and through utility penetrations and missing mortar joints. Most centipedes are nocturnal or active at night.
House centipedes commonly invade structures where they survive on silverfish, earwigs, flies, spiders and other soft-bodied prey. Centipedes are primarily carnivorous and obtain most of their moisture needs from their prey. Although they may be found anywhere in a house, the usual places are damp basements, bathrooms, damp closets and potted plants. Occasionally stone centipedes are found in homes and building near the foundation.
Cultural Control And Preventative Measures
The key to centipede control is to reduce or eliminate moist areas and harborage. For example, accumulations of leaves and grass clippings, logs, stones, rocks and stacked firewood should be removed from near the foundation. Indoors, conducive conditions (moisture retention) can be lessened by means of enhanced ventilation by strategic placement and use of fans, power vents and dehumidifiers. Centipede entry may be reduced by exclusion of structural gaps in the foundation and thresholds. Indoors, centipedes are easily removed with a vacuum cleaner.
A Rottler pest management professional can significantly reduce invasion by centipedes and occurrence of their prey indoors through periodic exterior perimeter treatments with residual insecticides, generously applied to building foundation walls, perimeter flower and ornamental planting beds and unfinished basement sill plates. In severe cases, non-residual aerosol insecticides can be used to treat pipe chases in wall voids and into crawl spaces.