The common insect often called a “pincher bug” is scientifically known as the earwig, belonging to the insect order Dermaptera. This name, which translates to “skin wing,” references the leathery forewings that cover the insect’s delicate, fan-shaped hindwings. Earwigs are easily identified by the prominent, forceps-like appendages, called cerci, that extend from the rear of their abdomen.
The Mechanism of the Pinch
The cerci are the earwig’s multi-purpose tool, and they are capable of delivering a pinch. This action is a physical grasp, not a sting or a bite, as earwigs lack a stinger and venom glands. Earwigs use these abdominal appendages for several functions, including capturing prey, defending themselves against predators, and assisting in the folding of their wings.
The design of the cerci differs significantly between the sexes. In males, the pincers are typically longer and strongly curved, resembling a pair of forceps. These exaggerated structures are frequently used as weapons in male-to-male combat for dominance and in courtship displays to the female.
Female earwigs, conversely, possess cerci that are shorter and straighter. Their pincers are primarily employed for defense, such as protecting their clutch of eggs from predators. When an earwig pinches a human, it is almost always a defensive reaction to being handled, trapped, or otherwise threatened.
Why Earwigs Are Not a Threat
Despite their intimidating appearance, earwigs are not considered dangerous to humans. The pinch from their cerci is typically harmless and rarely causes the skin to break. When a pinch does occur, the sensation is usually described as a minor, brief sting or a slight nip, causing only temporary discomfort.
Earwigs are neither venomous nor poisonous and do not transmit diseases to people. If the skin is broken, which is a rare event, the primary concern is the possibility of minor infection from soil-dwelling bacteria, necessitating simple wound cleaning. The myth that earwigs intentionally crawl into human ears to burrow into the brain is unfounded folklore.
This common misconception likely stems from the insect’s name, but earwigs are no more prone to crawling into ears than any other small, nocturnal insect. They are non-aggressive toward people and only use their defensive mechanism when they feel cornered or are accidentally pressed against the skin.
Where Pincher Bugs Live
Earwigs prefer environments that are cool, dark, and damp, as they require moisture to survive. They are nocturnal, spending the daylight hours hiding in protected spaces. Their natural habitats include areas under rocks, logs, leaf litter, mulch, and decaying wood.
Human encounters often happen when earwigs seek refuge in parts of a house that mimic these conditions. They may enter homes through small cracks in the foundation or gaps around doors and windows when outdoor conditions become too hot or dry. Once inside, they tend to congregate in high-humidity areas like basements, laundry rooms, and bathrooms.
They do not establish colonies indoors but enter seeking a more suitable microclimate. Earwigs can also be inadvertently carried inside on potted plants, firewood, or other items that were stored outdoors.