European Earwig

Overview

The European Earwig (Forficula auricularia), known simply across many temperate regions as the common earwig, is an iconic, nocturnal omnivorous insect belonging to the order Dermaptera (family Forficulidae). Instantly recognized worldwide by the prominent, pincer-like appendages (cerci) projecting from the tip of its abdomen, this glossy, reddish-brown insect is one of the most familiar and misunderstood creatures in urban gardens. Despite the ancient, unfounded folklore myth that earwigs burrow into human ears to lay eggs inside human brains, Forficula auricularia is completely harmless to humans and is renowned among entomologists for exhibiting extraordinary, highly evolved maternal care.

Ecologically, Forficula auricularia functions as a vital dual-role decomposer and biological pest controller in terrestrial soil ecosystems. Foraging actively under the cover of darkness, it consumes vast quantities of agricultural pests—particularly destructive woolly apple aphids, scale insects, insect eggs, and spider mites—acting as a natural biological control agent in commercial orchards and organic gardens. Concurrently, by feeding on decaying leaves, fungal spores, and carrion, earwigs accelerate the decomposition of forest litter and humus formation.

Biology and Physical Characteristics

Forficula auricularia possesses a flattened, elongated, highly flexible body colored rich chestnut-brown, with yellowish legs and antennae. Its defining visual signature is its pair of chitinous posterior forceps (cerci), which display pronounced sexual dimorphism: in males, the pincers are large, robust, and strongly curved like calipers with tooth-like bases, used for courtship rituals and fighting rival males; in females, the pincers are smaller, straight, and taper gently toward the tips. Although earwigs rarely take flight and appear wingless, they possess exquisite, short, leathery forewings (tegmina) beneath which lie tightly folded, translucent, fan-shaped hindwings folded ten times in a complex origami pattern. To defend against predators like centipedes and birds, earwigs arch their pincers over their heads like scorpions and emit a pungent, foul-smelling chemical cocktail from specialized abdominal scent glands.

Behavior and Ecology

European earwigs are strictly thigmotactic, possessing a powerful instinctual drive to squeeze their flat bodies into tight, dark, moist cracks where they experience physical contact on all sides. In autumn, a mated female digs a subterranean nest chamber beneath a flat stone or log, laying thirty to sixty pearly white eggs. Uniquely among non-social insects, the mother demonstrates fierce, devoted maternal brood care: she remains with the eggs throughout the freezing winter, continuously licking and rolling them to coat them with fungicidal secretions that prevent mold growth. When the nymphs hatch in early spring, the mother continues to feed, protect, and shelter them inside the underground nursery until their second molt, at which point the young disperse into the garden.

Conservation and Human Impact

The European Earwig is evaluated as globally secure and common (G5), maintaining thriving populations across Europe, North America, Australia, and New Zealand. While occasionally considered a nuisance by gardeners when they chew small holes in dahlia flowers or ripe peaches, modern agricultural ecologists recognize earwigs as valuable beneficial insects, particularly in apple and pear orchards where a single earwig can consume up to a hundred aphids per night. Orchardists frequently install rolled corrugated cardboard and straw traps in fruit trees to shelter and distribute earwig populations for natural biological pest suppression.

Interesting Factoid

The European earwig is an insect supermom: unlike almost all other solitary insects that abandon their eggs, the mother earwig spends the entire winter underground painstakingly licking every single egg thousands of times to keep them clean and free of deadly fungus until they hatch.