The common name of “earwig” comes from an old European superstition that these insects enter the ears of sleeping people and bore into the brain. This belief is without foundation. The forcepslike cerci are apparently used as both offensive and defensive weapons, and are sometimes used to capture prey. Earwigs are worldwide in distribution, with about 22 species occurring in the United States.
Adults about 1/4-1″ (5-25 mm) long, with body elongate, flattened in form. Color varies from pale brown with dark markings to uniformly reddish brown to black, but with paler legs. With 4 wings (rarely wingless), front wings leathery, short, and meeting in a straight line down the back whereas, hind wings membranous, fan-shaped, and folded under front wings. Nymphs similar to adults but have no wings.
Earwigs typically overwinter outdoors as adults in protected situations. The European earwig overwinters in pairs in earthen cells 1 1/8-1 1/2″ (30-40 mm) beneath the surface and the striped earwig in subterranean burrows or chambers. The females lay and tend their eggs in these underground situations and then tend the newly hatched nymphs. Earwigs have 4-5 nymphal instars. Nymphal development averages about 56 days (range 40-60) for the striped and takes about 68 days for the European earwig, both having 4 instars. European females lay about 30-55 eggs the first batch and many fewer the second time. The striped female lays about 50 eggs the first time and may lay 3-4 more batches. The red-legged female lays about 40-53 eggs on the average and its 5 nymphal instars require about 80 days to complete development. Some females may live as long as 7 months after attaining maturity. Earwigs have a distinctive disagreeable/repugnant odor which is released when they are crushed, but some species can squirt such a liquid. They are gregarious in nature, typically occurring in groups. Red-legged earwigs have been reported to cause minor skin abrasions in humans.
Earwigs are nocturnal or active at night and hide during the day in moist, shady places such as under stones or logs, or in mulch. Neither the eggs nor nymphs can withstand long periods of dryness. Earwigs feed on live or dead plants and/or insects. At times they damage cultivated plants. The European earwig occasionally damages vegetables, flowers, fruits, ornamental shrubs, and trees, and has been recorded as feeding on honey in beehives. The red-legged earwig has been recorded as a pest of Irish and sweet potatoes in storage, damaging the roots of greenhouse vegetables, and as a pest in flour mills, breweries, meat-packing plants, slaughter houses, gardens, and nurseries. The striped earwig has not been recorded as damaging plants. Earwigs are attracted to lights or to insects attracted to lights. Usually it is the European and red-legged earwigs which occasionally invade homes, sometimes by the hundreds or thousands.
The key to control is the removal of unessential mulch, plant debris, and objects such as stones and boards from around the structure. The purpose of this is to establish a low-moisture zone which is disagreeable to earwigs. Micro-encapsulated and wettable powder residual formulations applied as 3-10 foot (1-3 m) band treatments are particularly effective. Baits are very effective. Indoor control is supplemental to the outdoor control measures.