Earwigs can be recognized by their cerci – two small appendages located at the end of the rear portion of their reddish brown bodies. The cerci are more curved in the male and straighter in the female. Their two wings are folded so elaborately that they are rarely used for flight, and only the other two, smaller, thick wings covering them are visible.
Unlike larger animals and humans that generally produce few offspring but raise them afterwards, nearly all insects opt for a different strategy that consists of producing more descendants but not investing any energy taking care of them. Earwigs are the exception among the insects since the female withdraws to a nest a few centimetres underground after mating where she lays her eggs and spends the winter taking care of them. She incubates them, cleans them to remove any mildew, keeps them in one place, and can even move them to shield them from temperature or moisture variations. The eggs hatch in spring. The female also cares for the young larvae for a period of two to three weeks during which she protects them and feeds them. The larvae, that gradually start to resemble adults as they develop, begin their nocturnal explorations toward the end of May; they then leave the nest and the female dies. These insects are active at night. During the day, they hide under bark, a stone, a woodpile, or in cracks. They can secrete a liquid that produces a foul-smelling odour.
Places where they can be found in the home
Earwigs feed on decomposing materials and other insects (sometimes, their fellow earwigs), fungus, tender leaves, flowers, fruits and vegetables, so their preferred habitat is outdoors. On the other hand, the soil around the foundation of a house or cracks in the foundation itself can provide a good place to spend the winter. When spotted inside a house, they are usually just passing through looking for food and shelter. They do not reproduce indoors. If you find them there during the day, it could be because their numbers are high in the surrounding area, but it is also possible that their presence is due to the introduction of cut flowers. They can generally be found under flower pots, in garden furniture crevices or in the garage.
When they have access to an environment that provides them with food and shelter, earwigs do not really cause any damage. Complaints about them are sometimes linked to recently landscaped areas on mostly bare and un-composted soil. The current way we design our vegetable gardens (close rows and bare soil) obliges them to attack our plants since they can find no other source of food there. To ensure that we, alone, benefit from the vegetables we plant, it is better to start seedlings indoors and transplant them as soon as possible or whenever they are strong enough to withstand some damage. To keep earwigs out of the house, fill or plug cracks or install screens in small openings where they can enter. It is also better not to provide them with shelter by leaving debris (plant or other kinds) around the house, and to trim any foliage in contact with the house.
When we notice pest damage in the garden, we should first make sure it was actually caused by earwigs. A nocturnal visit using a flashlight may help discover that the damage was caused by slugs or caterpillars.
Turning the soil in vegetable gardens and borders very early in spring will disturb the adults and expose the insects’ eggs to inclement weather and their enemies (predators and parasites). Removing debris, grass cuttings, and dead leaves from the ground will prevent them from finding shelter. On the other hand, adding compost will provide shelter for the small organisms that earwigs feed on and prevent them from attacking our plants.
Traps have been proven to be highly effective in controlling these insects outdoors, because they hide inside them. Use a rubber band to hold together two pieces of embossed paperboard with the grooves facing each other so that earwigs can enter, and place them in areas they frequent such as the vegetable garden or close to trees or the house. A bamboo stem, a rubber tube, a wet rag, or a rolled up sheet of newspaper are also good shelters. As bait, a can containing a small amount of fish (tuna or sardines) and oil (vegetable or fish) or moistened bread crusts can be left on the ground before nightfall and examined the following morning. The individuals that fell into the trap can be killed in soapy water.
Diatomaceous earth, prepared from microscopic aquatic organisms, can be spread around so that the earwigs will scratch their bodies when they rub against it and die of dehydration. The humidity in the basements of houses must be reduced to make the environment less conducive to their survival. Insecticides are sometimes used for heavy infestations. They are most often needed outdoors rather than inside.
Earwigs owe their name to the belief that they would be capable of entering ears and piercing eardrums. If an earwig did accidentally enter someone’s ear canal, it would simply be because it was looking for a dark natural or artificial cavity to hide in, since it is not particularly attracted by our ears or us! The most it can do is arch its body and use its cerci to pinch us in self defence. It also uses them during mating and to fold up its wings after flight. Females will sometimes use them when fighting over a source of food.
Contrary to what people might think, this insect is rather useful since, for example, it eats aphids in orchards, pollinates flowers, and serves as food for other animals. Deciding to kill them would more likely be due to the fact that people don’t like the way they look, rather than for the damage they cause.