- Forficula auricularia, commonly known as the common earwig, is a well-known insect belonging to the order Dermaptera and the family Forficulidae. This species is widely distributed throughout Europe, Asia, North America, and parts of North Africa and Australia, making it one of the most cosmopolitan members of its order. It thrives in a wide range of environments, including gardens, fields, orchards, forests, and urban areas, where it can be found hiding in moist, dark places such as under stones, bark, leaves, or flowerpots during the day. Despite its intimidating appearance, F. auricularia is largely harmless to humans and plays an important ecological role in both natural and agricultural ecosystems.
- Adult Forficula auricularia are elongated, flattened insects typically measuring 12 to 16 millimeters in length. Their bodies are dark brown or reddish-brown, with lighter-colored legs and yellowish-brown wing covers (elytra). The most distinctive feature of this species is its pair of curved forceps-like cerci at the end of the abdomen. These cerci, which resemble pincers, are sexually dimorphic: in males, they are larger, more robust, and curved outward, while in females, they are smaller, straighter, and less curved. The cerci serve multiple purposes, including defense, prey capture, courtship, and folding of the wings beneath the short, leathery forewings.
- Although F. auricularia possesses two pairs of wings, it rarely flies. The forewings (elytra) are short, leathery covers that protect the large, membranous hindwings, which are intricately folded beneath them when not in use. When flight does occur, the unfolding of the hindwings is a remarkable process, as they expand in a fan-like manner before being precisely refolded with the aid of the cerci. The head of the earwig bears chewing mouthparts, compound eyes, and short, segmented antennae. The thorax is well-developed, supporting strong legs adapted for rapid movement and grasping surfaces.
- The behavior of Forficula auricularia is primarily nocturnal. It hides during the day in damp, sheltered locations and becomes active at night to feed. Its diet is omnivorous, consisting of both plant and animal matter. Earwigs feed on decaying organic material, fungi, small insects, aphids, and soft plant tissues such as petals, leaves, and fruits. This dual feeding habit has earned them a mixed reputation—while they are beneficial predators that help control pest populations like aphids and caterpillars, they can also cause minor damage to crops and garden plants, particularly under conditions of food scarcity.
- One of the most fascinating aspects of F. auricularia biology is its maternal care, which is unusually advanced among insects. After mating, which typically occurs in late summer or autumn, the female excavates a nest chamber in the soil or under debris where she lays a clutch of 30 to 60 oval, white eggs. She remains with her eggs throughout the winter, guarding, cleaning, and tending to them to prevent fungal infection and desiccation. This maternal behavior continues after the eggs hatch in spring; the mother feeds and protects the young nymphs until they are capable of independent life. Once they disperse, the mother dies shortly thereafter. This level of parental investment is rare in insects and is a defining characteristic of earwigs.
- The life cycle of Forficula auricularia involves incomplete metamorphosis, consisting of three stages: egg, nymph, and adult. The nymphs resemble miniature adults but lack fully developed wings and reproductive organs. They undergo several molts over a period of 6 to 10 weeks, gradually acquiring adult features. Under favorable conditions, F. auricularia can produce one or two generations per year, depending on climate and food availability.
- Ecologically, Forficula auricularia plays a dual role as both a predator and a scavenger, making it an important component of soil and garden ecosystems. By consuming dead organic matter, it contributes to decomposition and nutrient cycling, while its predation on pest insects provides natural biological control in agricultural settings. However, in high populations, earwigs may become minor pests, damaging flowers, fruits, and vegetables such as strawberries, lettuce, and corn.
- Despite folklore suggesting that earwigs crawl into human ears—hence their name—this behavior is largely mythical. The name “earwig” likely derives from the Old English ēare (ear) and wicga (insect), possibly referencing the shape of their folded wings, which resemble human ears. In reality, F. auricularia poses no threat to humans and seldom enters living spaces except by accident.
- From an evolutionary and anatomical perspective, Forficula auricularia is a fascinating insect that demonstrates primitive wing-folding mechanisms, complex social behaviors, and adaptations to nocturnal life. Its success across a wide geographic range is attributed to its ecological flexibility, resilience, and reproductive strategies.
