The name earwig comes from a European superstition that these insects entered the ears of a sleeping person and bored into the brain. This belief is totally unfounded. Earwigs do often cause alarm to homeowners when discovered indoors, despite the fact that they are harmless to humans. They have a frightful appearance, move rapidly around baseboards at the ground level and may emit a foul-smelling, yellowish-brown liquid from their scent glands. Active at night and hiding during the daytime, earwigs normally live outdoors and do not establish themselves indoors. They are harmless to humans and animals, although if handled carelessly, the earwig can give a slight pinch with the forceps. Earwigs can be responsible for serious feeding damage on flowers, vegetables, fruits and other plants, giving the leaves a ragged appearance with numerous, small, irregular holes.

Description:

Earwigs are elongate, flattened insects, ranging from light red-brown to black and are easily recognized by their forcep-like appendages (pincers) on the end of the abdomen. The forceps (cerci) are unequal in length in the males. Earwig female forceps are straight-sided, whereas male forceps are strongly curved (caliper-like) and larger. They have chewing mouthparts and long, slender antennae. Some species are wingless but others have a pair of leathery forewings covering a few segments of the abdomen and the membranous hind wings, which have the tips protruding. There are many species of earwigs: the European earwig ranges from 13-20 mm (1/2 to 3/4 inch) in length, with banded legs and reddish head; the ringlegged earwig ranges from 13-18 mm (1/2 to 3/5 inch) in length and is black-yellowish underneath with legs having dark crossbands. Young earwigs (nymphs) are similar in appearance to adults. They are white to olive-green and lack wings.

An earwig's forceps are used to defend the nest, capture prey, probe narrow crevices and fold or unfold wings. Earwigs are primarily scavengers on dead insects and rotted plant materials. Some species are predators, feeding on aphids. Only a few of the winged species are good fliers. They are often transported great distances in plant materials and occasionally in other freight. Earwigs require moist, cool places and are found in damp crawl spaces, flower gardens near the home, in mulches, compost piles, trash, under boards and in wood piles. After entering houses, they feed on sweet, oily or greasy foods or houseplants. They are attracted to lights.

Life Cycle:

Earwigs develop from egg to adult through gradual metamorphosis with four to five nymphal instars or stages. During the spring or autumn, females lay 20 to 50 smooth, oval, pearly-white or cream-colored eggs in a below-ground chamber (upper two to three inches of soil). The female moves, cleans and provides maternal care by protecting the eggs and new young until the first molt. Young then leave the nest, fend for themselves and mature in one season. Most species in this country have one generation per year, overwintering as eggs or adults in the soil. Earwigs may dig as deep as six feet below ground to escape the cold temperatures.

Damage:

Some feed on living plants and often become pests in greenhouses and field crops.

Control:

Prevention: For best control indoors, one must first control earwigs outdoors. Since they are attracted to lights, reduce lighting around doors, windows and other potential entry sites. Use good night light discipline and special sodium vapor yellow lights (less attractive to insects) instead of white, neon or mercury vapor lights.

Earwigs need and are very attracted to moisture. High populations, practically invisible during the day, may be present around foundations, in landscaped yards, in mulch, under boards, etc. Be sure to eliminate damp, moist conditions in crawl spaces under houses, around faucets, around air-conditioning units and along house foundations. Rain gutters and spouts should carry water away from the house foundation. Use caulking compound, putty and weather stripping around doors, windows, pipes and other entry sites, especially at the ground level. Change landscaping by creating a clean, dry border immediately around the foundation wall. Gravel or ornamental stones can make an attractive barrier against earwigs and other pest invaders.

Trapping: Earwigs can be trapped outdoors in cardboard boxes baited with oatmeal or bran with pencil hole size entry sites punched in the sides near the bottom. Place burlap bags, canvass, boards, newspapers or other cover material in mulch, shrubbery and similar habitats to collect individuals the following day. The adults can be squashed by hand or vacuumed with a "shop vac." Indoors, remove with broom and dustpan or by vacuum cleaner.

Adapted from the Virginia Cooperative Extension and the Ohio State University Extension, 1999