The earwig is an insect belonging to the order Dermaptera. This common arthropod is often considered a household pest, largely because of its alarming appearance, though it primarily lives and feeds outdoors. While the earwig’s reputation suggests it seeks out human ears, this is a long-standing myth, and the insect is generally harmless to people. Identification relies on observing its distinct body shape, size, and the prominent pincers at its tail end.
Overall Body Structure and Size
The earwig possesses an elongated and relatively flattened body structure. Most species measure between 12 and 15 millimeters long, though some tropical species can reach up to 50 millimeters. The body is divided into three distinct sections: the head, the thorax, and the segmented abdomen.
Their coloration typically ranges from a reddish-brown to a dark, glossy brown, providing effective camouflage in soil and decaying matter. The head is equipped with a pair of long, segmented antennae, which they use to sense their surroundings. They also possess three pairs of legs, which are usually a lighter, yellowish-brown color.
The earwig’s wings are a defining feature that is often overlooked because they are usually hidden. The first pair of wings, called tegmina, are short and leathery, serving as protective covers for the second pair. Beneath these short forewings are large, delicate, semicircular hindwings, which are intricately folded. Despite having fully functional wings, earwigs rarely take flight and prefer to travel by crawling.
The Distinctive Pincers (Cerci)
The most recognizable characteristic of the earwig is the pair of prominent, hardened appendages located at the end of its abdomen, known scientifically as cerci, or more commonly as pincers or forceps. These structures are rigid and tough, and they can be maneuvered using the insect’s flexible, muscular abdomen. The pincers are used for defense against predators, grasping prey, and assisting in folding their large hindwings under the protective forewings.
A close look at the cerci can reveal the insect’s sex, as they exhibit clear sexual dimorphism. In the female, the pincers tend to be relatively straight and uniform, resembling a small pair of scissors. Male earwigs, by contrast, possess cerci that are significantly longer and distinctly curved or strongly hooked. When threatened, an earwig will often raise its abdomen and carry the cerci over its body in a defensive posture, similar to a scorpion.
Common Habitats and Movement Indoors
Earwigs are largely nocturnal insects that thrive in environments where moisture and darkness are readily available. Outdoors, they are typically found hiding during the day under rocks, mulch, leaf litter, decaying wood, and in the crevices of tight spaces. They are common residents of garden beds and areas near building foundations where organic debris accumulates.
Their presence inside a home is usually a temporary situation that occurs when they are seeking shelter from unfavorable outdoor conditions. Earwigs frequently move indoors when the weather becomes either too hot and dry or excessively wet, as they require a humid environment to prevent desiccation. They enter structures by crawling through foundation cracks, gaps around doors and windows, and utility line openings.
Earwigs are also known to “hitchhike” inside inadvertently on items brought in from outside, such as potted plants or cardboard boxes stored in damp areas. Once inside, they will gravitate toward dark, moist locations like basements, laundry rooms, or bathrooms. They do not typically establish permanent breeding colonies inside a dry home, preferring to return to the soil and leaf litter once favorable conditions allow.