Facts, Identification & Control
Earwigs are small insects of the order Dermaptera, which takes its name from the Greek words “derma,” meaning skin, and “ptera,” which means wings. The name refers to the thick forewings that cover and protect the hind wings of the insect. The common name of the earwig is actually a misnomer stemming from the early European belief that the insect would crawl into the ear canal of a sleeping person and bore into the brain. In reality, earwigs rarely do any more harm to people than an occasional nip to the skin when defending itself. Despite being generally perceived as a pest, the earwig is a beneficial insect because it helps in the decomposition of detritus and feeds on destructive insects.
Appearance / Identification
There are several species of earwigs, with the European earwig (Forficula auricularia) being the most common in Canada. As the name suggest, it was first introduced from Europe and is now well established in North America. It is dark-red in colour with prominent pincer-like appendage (cerci) at the tip of its abdomen. It measures about 16 mm long, with pale yellow wings and legs. The antennae are long with 12 segments. In preparation for flying, earwigs have been observed to climb as high as possible before taking flight. However, they do not typically fly and prefer to run from one place to another.
Earwigs tend to prefer dark places rich in moisture and prefer to forage at night. The insects therefore rest in narrow cracks in foundations, under floorboards, and in other tight spaces around the home. In nature, they may appear under tree bark or beneath stones. The insects also release a pheromone in their feces that attracts other earwigs to the spot.
Earwigs are omnivorous; they feed on dead or decaying vegetable matter, dead insects, and other small invertebrates. They use their cerci to grab and hold prey, including spiders, aphids, and even caterpillar pupae, before bending back in order to move the food to their mouthparts. Earwigs also feed on plants and, consequently, can cause injury to plants.
Life Cycle / Reproduction
Earwigs undergo an incomplete metamorphosis made up of three stages: egg, nymph, and adult. Females initiate the cycle by laying between 20 and 60 eggs in burrows in a suitable environment. After about seven days, the young emerge from the eggs as nymphs. Generally resembling adult earwigs, nymphs pass through four stages, called instars, before fully maturing. Earwig nymphs live in the nest during the first two instars, begin to forage freely during the third one, and leave the nest completely upon reaching adulthood. Nymphs typically develop into adults in late summer or early fall. Adult earwigs can survive cold weather.
Problems Caused by Earwigs
Even though they feed on refuse and certain harmful insects, earwigs may still pose multiple problems for home and business owners. The pests present various issues by feeding on flowers, vegetables, ornamental trees, and shrubs. In large enough numbers, earwigs can eventually kill healthy plants. Additionally, humans and pets are sometimes recipients of defensive pinches from earwigs when the insects feel threatened. Earwigs also possess a gland that discharges a foul-smelling yellow to brown liquid as another defence mechanism.
Detection / Signs of Infestation
Although earwigs are not typically encountered in large numbers, the easiest way to identify an earwig infestation is seeing the insect firsthand. Damp and dark basement areas with multiple cracks in the foundation provide perfect hiding places for the pests. Garbage and refuse may also attract earwigs, as will piles of leaves, vegetation, and mulched areas. The insects release pheromones which may lead other earwigs to assemble in the area. Populations may increase during nesting, as well.
The easiest and most complete way of preventing earwigs from entering a structure is to modify the surrounding area. Get rid of all decaying vegetation, such as leaf piles, grass clippings, and compost heaps, to get rid of potential nesting sites. Fix leaky downspouts, reroute drains when necessary, and repair broken irrigation systems to eliminate the moist, dark areas where earwigs flourish. While pesticides and traps may work, these methods cannot guarantee total removal and may present dangers to people and pets if used improperly. To fully remove an earwig infestation and reduce the chances of future problems, call a pest control professional.
Learn more about earwigs:
Earwigs in Ear