Latin Name: Forficula auricularia
Found everywhere except Antarctica, the common, European Earwig is an introduced species in North America that has been thriving in Canada for the last 30 years. Few earwigs survive cold climates, but in the summer months they are likely to be found in tight crevices in woodland, fields, gardens, picnic tables, compost and waste bins, patios, lawn furniture, window frames, or between your sheets; anything with tiny spaces can potentially harbour them. Although it would require a huge population, there are instances where earwigs have done considerable damage to fruit and vegetable crops in Europe. About 25 of 1800 species of earwig occur in North America. The spine-tailed earwig (Doru aculeatum) is the only native species of earwig found Canada, where it hides in emerging plants in southern Ontario wetlands. Despite their scary appearance and reputation, earwigs are not directly harmful to humans; there is no evidence that they transmit disease. Opportunistic omnivorous-scavengers, earwigs are typically beneficial for lawns and gardens as they feed on decaying matter, slug eggs, insect larvae, aphids, and other garden pests. Often believed to be dangerous, their pincers cause little or no harm to humans. In high earwig population neighbourhoods, establishing physical controls in early spring is the best approach to population control.
Red-brown in colour, earwigs have a pair of forceps-like pincers on their abdomen, and membranous wings folded underneath protective forewings, hence the scientific order name, “skin wings”. Nymphs appear similar to adults but are smaller. Adults typically measure around 2 cm in length.
Earwigs can typically live for about a year. The male and female start mating in the autumn and can be found together in the fall and winter. They will live in a chamber in debris, crevices, or soil 1” deep. After mating, the sperm may remain in the female for months before being used for egg fertilization. Between midwinter to early spring, the male will either leave the nest or be driven out by the female. Afterwards, the female will lay 20 to 80 tiny pearly white eggs over a two-day span that become kidney shaped and brown right before hatching (in about seven days). The mother may assist the nymphs in hatching and will protect them until their second moult. Nymphs consume food regurgitated by the mother and on their egg casings and moults. If the mother dies before the nymphs are ready to leave, they will eat her. After several instars, the nymphs will moult into adults. The male’s forceps will become curved, while the female’s forceps remain straight. They will also develop their natural colour, ranging from light brown to dark black.
Earwigs are mostly nocturnal and often hide in small, moist crevices during the day, and are active at night, feeding on a wide array of living and dead plant and animal matter. Observed prey includes plant lice, but also larger insects like bluebottle flies and woolly aphids. Earwigs also feed on clover, dahlias, zinnias, butterfly bush, lettuce, cauliflower, berries, sunflowers, cornsilk, celery, peaches, plums, potatoes, roses, seedling beans and beets, grass shoots and roots. They sometimes even eat each other. During the summer they can be found in cool, damp and dark areas under stones, hollow aluminium doors, garden furniture and in bathrooms; in shady cracks or openings or anywhere that they can remain concealed during daylight. Earwigs begin searching for food at dusk and may begin to wander into homes in June or July. Although they are accidental invaders, it can be unnerving to find these insects among food and clothes and occasionally between bed covers.
Earwigs are preyed upon by birds, amphibians, lizards, centipedes, assassin bugs, and spiders. Their primary insect predators are parasitic tachinid flies, whose larvae are endoparasites and have long been used as a biological control of earwigs. Yellowjacket wasps prey upon earwigs when abundant, and they commonly host parasitic fungi and mites in great densities. Earwigs also cannibalize each other.
Relationship with Humans:
Earwigs do not transmit diseases to humans, and it is a common myth that earwigs crawl into the ear to lay eggs in the brain. They have been known to cause economic losses in fruit and vegetable crops, although they can also be beneficial. Homeowners often find them in kitchens, basements, bathrooms, and laundries but will turn up in any area of the house seeking moisture. They are ultimately outdoor insects.
In high earwig population neighbourhoods, establishing physical controls in early spring is the best approach to population control, and the most important part of controlling earwigs is eliminating their hiding places. Earwig harborages can be destroyed by disturbing the soil on your lawn, newly laid eggs will be exposed to a dry surface and will be less likely to hatch and survive. The perimeter of your property should be kept clear of debris and rotting organic material that could create a damp and shady shelter for potential harbourages. A dry zone approx. 1’ around the foundation of your home should be sufficient, so it is important to ensure that downspouts and gutters drain away from your property. Repair cracks, window frames, screens on vents, windows and doors to block passages into the home as inclement weather conditions may lead earwigs to find shelter in human living spaces. Damp basements create hospitable conditions for earwig infestations; a dehumidifier may help. Insects are attracted to white light, consider installing yellow bulbs, and directing the light towards your property. If they’ve entered your home earwigs may feed on indoor plants and can commonly be found in the saucer under plant pots. Start your vegetable gardens early and inspect all plants and produce that are brought indoors for home invading insects.
Health Canada provides an excellent resource of clever and inexpensive traps that can be created using household materials in your effort to control your property’s earwig population.
Physical control methods are not always enough and sometimes need to be implemented in tandem with the use of pesticides, a licensed technician from Addison Pest Control will be able to tailor an integrated pest management program for your pest population.