SCORES & OUTDOORS: The frightening and harmless earwigs

by Roland D. Hallee
Recently, someone showed me a photograph of an insect they alleged bit one of their children. They wanted to know what it was and whether it was harmful. It didn’t take long for me to identify it as an earwig.
Earwigs are a relatively small group of insects. Earwigs often upset people when discovered indoors. Their forcep-like tail appendages make them look dangerous, but they are quite harmless. Earwigs run rapidly around baseboards, and they may emit a foul-smelling, yellowish-brown liquid from their scent glands when disturbed or crushed. Earwigs are mainly active at night, usually hiding during the daytime. They’re often found in clusters hiding in dark crevices like door or window frames.
Earwigs normally live outdoors and do not establish themselves indoors, though the ringlegged earwig is a common resident in greenhouses. Earwigs are harmless to humans and animals, though if picked up and restrained, adult earwigs can give a slight pinch with the forceps. While mainly predaceous on other insects, earwigs often feed on flower petals, soft vegetables and fruits, or seedling plants when hot and dry conditions persist.
The name earwig actually comes from an Old English name, which was derived from the superstition that earwigs can enter your ears at night and burrow into your brain to lay eggs. This belief is totally unfounded, though earwigs will occasionally seek out ear canals of campers as dark, moist hiding places. This can obviously be a traumatic experience!
Adults of the European earwig are usually winged, while the ringlegged earwigs are wingless. If wings are present, the first pair are hard, short, and scale-like, while the second pair are membranous, fan-shaped, and folded under the hard first pair of wings. Tips of the second pair of wings usually protrude from under the first pair. The European earwig ranges from 1/2 to 3/4 inch long, with banded legs and a reddish head. The ringlegged earwig ranges from 1/2 to 3/5 inch long and is black-yellowish underneath with legs having white crossbands at the joints. Young earwigs (nymphs) are similar to adults except the nymphs lack wings and the cerci are short.
Earwigs develop from egg to adult through gradual, or incomplete, metamorphosis with four to five nymphal instars. Generally, most earwigs lay eggs in late winter into early spring in chambers in the ground, under logs, or under stones. Usually, 20 to 50 smooth, oval, pearly-white or cream-colored eggs are produced. The female moves, cleans, and provides maternal care by protecting the eggs and new young until the first molt.
When spring weather is suitable, the female makes an opening to the soil surface where the young nymphs can leave the nest and forage for food. The small nymphs often return to their burrow during the day, but soon they are large enough to fend for themselves without a burrow. Earwigs are active at night and are often found around lights preying on other small insects that come to lights. During the day, earwigs hide in moist, shady places beneath stones, boards, sidewalks, and debris. They are rapid runners and feed on mosses, lichens, algae, fungi, insects, spiders, and mites, both dead and alive.
Earwigs rarely fly and are unable to crawl long distances, but they often hitchhike in laundry baskets, cut flowers, luggage, newspapers, lumber, baskets of fruits and vegetables, automobiles, etc. They prefer moisture and may migrate indoors during periods of prolonged heat and drought. Forceps at the end of the abdomen are used to defend the nest, capture prey, probe narrow crevices, and fold or unfold wings.
If earwigs are persistently invading a home or building, one should first attempt to control the earwigs outdoors. Since earwigs breed in soil chambers and spaces under landscape stones and timbers, reducing mulch layers and landscape structures can help reduce populations.
During dry, hot weather, earwigs sometimes migrate indoors in search of cool and moist habitat. They are easily killed by residual insecticide treatments in cracks and crevices, along baseboards, beneath cabinets, along door and window sills, and in other hiding places during the day. Unfortunately, control will be short-term due to new earwig entry from outdoors. Therefore, the best strategy is to better seal around doors and windows, which serve as the major entry points.
They are plentiful, ominous looking, but they are harmless to humans. I just don’t care to be pinched by one.
Roland’s trivia question of the week:
Which major league players were known by these nicknames. 1. The Splendid Splinter. 2. The Bambino. 3. Charlie Hustle. 4. The Say Hey Kid.