Earwigs are common insects, instantly recognizable by the distinctive pair of forceps-like appendages, known as cerci, extending from the rear of their abdomen. They are nocturnal scavengers found globally. Earwigs are generally considered a nuisance pest in gardens and around human dwellings due to their occasional damage to plant foliage and their tendency to aggregate in large numbers.
Geographic Spread Across the United States
The distribution of earwigs across the United States is largely dominated by a single invasive species, the European earwig (Forficula auricularia). This insect was first recorded on the West Coast, specifically in Seattle, Washington, around 1907, and shortly thereafter was noted on the East Coast in Rhode Island in 1911. Since these initial introduction points, the European earwig has successfully spread across most of the continental U.S., thriving particularly well in temperate climates.
Today, this species is nearly ubiquitous throughout the New England, Mid-Atlantic, and Pacific Western states, where moisture and moderate temperatures are abundant. Earwigs are highly dependent on human activity for their wide-ranging dispersal, frequently hitchhiking across state lines in nursery stock, lumber, and other transported goods. Populations are significantly less common in the most extreme climates, such as the arid deserts of the Southwest or the high-elevation, cold-climate mountain ranges. These insects are poorly adapted to areas lacking consistent moisture, which limits their establishment in undisturbed, dry habitats.
Preferred Outdoor Environments
Earwigs are primarily outdoor dwellers whose survival depends on finding micro-habitats that provide both shelter and high humidity. Their preference for dark, cool, and damp locations is directly tied to their biological need to prevent desiccation. During the daytime, these nocturnal insects retreat into crevices and protected spaces where moisture is readily retained.
Common outdoor living spaces include dense leaf litter, garden mulch, and piles of grass clippings or other decaying organic debris. They frequently aggregate beneath rocks, stepping stones, and logs that provide an insulating layer against daytime heat and sunlight. Earwigs also burrow a short distance into the top layer of soil, particularly in rich earth, which is where females will construct small nests to lay and guard their eggs.
Proximity to structures like fences, woodpiles, and building foundations also creates favorable conditions by offering numerous cracks and protected voids for shelter. These environments act as humid refuges, allowing the insects to conserve water while waiting to forage at night. Their omnivorous diet is easily accessible in these same damp, protected areas.
Transitioning to Indoor Habitats
The movement of earwigs from their preferred outdoor habitats into human structures is usually an accidental migration driven by environmental stress. Adverse weather conditions, such as prolonged drought or excessive rainfall, often prompt earwigs to seek more stable shelter indoors. Their presence inside a home is generally temporary, as the dry interior environments do not sustain them long-term.
These insects enter dwellings by exploiting numerous small structural vulnerabilities around the foundation perimeter. Common entry points include minute cracks in concrete, gaps under loose-fitting doors, and openings around utility pipes or electrical conduits. Once inside, they are immediately drawn to areas that inadvertently replicate their favored damp, dark outdoor conditions.
Interior locations that frequently harbor earwigs include basements, crawl spaces, and ground-floor rooms with accidental moisture sources. Laundry rooms, bathrooms, and kitchens are attractive because of potential condensation, leaks, or plumbing issues that keep the environment humid. Earwigs found in these areas are not usually breeding inside but are simply sheltering, often hiding in tight spaces behind baseboards, appliances, or in damp fabric until conditions outside become more favorable.