Earwigs are common garden insects, recognized by their slender bodies and distinctive rear appendages, that often appear indoors. They belong to the insect order Dermaptera, which includes over 2,000 species found across every continent except Antarctica. Understanding their natural history reveals they are not merely pests but play a beneficial role in the environment, as their interactions with human spaces are largely accidental.
Identification and Defining Features
The most recognizable feature of the earwig is the pair of pincer-like appendages, scientifically known as cerci, located at the tip of their abdomen. These cerci are hardened and vary in shape between the sexes; males typically have more curved cerci, while females have straighter ones. Their bodies are generally dark reddish-brown and elongated, measuring about one-half to three-quarters of an inch in length.
The cerci serve multiple functions, including defense against predators and use in mating rituals. They also use these forceps to capture and hold smaller prey or food items. Additionally, they help precisely fold their large hindwings beneath the small, protective forewings after a rare flight. Although the pincers look intimidating, they are not designed to attack humans.
The Earwig’s Ecological Function
Earwigs are omnivores, consuming both plant and animal matter, which places them in the role of nature’s recyclers. They are primarily scavengers, consuming decaying organic matter such as composting leaves, fallen fruit, and dead insects. This feeding habit aids the decomposition process, helping return nutrients to the soil and cleaning the environment of detritus.
Many earwig species also act as secondary predators, providing natural control for smaller, soft-bodied garden pests. They actively hunt and feed on insects like aphids, mites, and various larvae. This predatory behavior makes them beneficial to gardeners by protecting plants from common pests. Furthermore, earwigs serve as a food source for a variety of animals, including birds, spiders, lizards, and frogs, integrating them into the larger food web.
Separating Fact from Earwig Fiction
The common name “earwig” originates from the old English term Δ“are-wicga, which translates to “ear wiggler,” leading to a persistent cultural myth. This folklore claims the insects intentionally crawl into the ears of sleeping people to burrow into the brain or lay eggs. Modern science has debunked this notion, stressing that the ear canal is not a suitable habitat for an earwig.
Their natural habitat is in damp, dark crevices, not the warm, waxy environment of a human ear. While accidental entry of any small insect into an ear can occur, documented cases involving earwigs are extremely rare. Although their pincers look threatening, they are not medically dangerous to humans. They do not sting, and while they can administer a light pinch if handled roughly, their cerci are not strong enough to break the skin.
Reasons Earwigs Seek Shelter Indoors
Earwigs prefer to live outdoors in areas providing consistent moisture, darkness, and shelter, such as under stones, logs, or leaf litter. They are nocturnal and highly sensitive to changes in their environment, particularly dryness. They wander inside a structure when their outdoor habitat becomes inhospitable due to weather conditions like drought, heavy rain, or extreme heat.
The insects seek to replicate the cool, damp conditions they prefer, leading them to areas of high humidity inside a home. They are frequently found in basements, bathrooms, laundry rooms, and under sinks, where they find moisture from leaky pipes or condensation. Earwigs enter a home through tiny cracks in the foundation, gaps around utility pipes, or openings near doors and windows. They often do this accidentally while searching for a more stable microclimate.