The European earwig, Forficula auricularia, originated in Europe, western Asia, and northern Africa, but has since become distributed worldwide. It is now a frequent presence in North America and other continents, having spread largely through human activity, such as transportation on commercial goods and nursery stock. This nocturnal insect is commonly encountered because it spends daylight hours hidden in dark, cool, and moist crevices, often leading it into homes and gardens. Although sometimes considered a nuisance due to its tendency to invade structures, the European earwig plays a complex role in its environment, acting as both a garden pest and a beneficial predator.
Identifying the European Earwig
The adult European earwig has an elongated, flattened body, typically measuring 12 to 15 millimeters in length. Its coloration is a consistent dark reddish-brown, with the legs and wing covers often appearing a duller yellow-brown. The insect possesses a pair of short, leathery forewings covering membranous hindwings, though it rarely uses them for flight.
The most prominent feature is the pair of forceps-like appendages, known as cerci, located at the tip of the abdomen. These cerci display sexual dimorphism. In females, the cerci are relatively straight, slender, and hardened, measuring about 3 millimeters long, and are primarily used for defense of the egg clutch.
The male’s cerci are longer, more robust, and distinctly curved, sometimes reaching 4 to 9 millimeters in length. They are used in courtship displays and fights with other males. Male cerci can vary in size and shape within the population, ranging from shorter, highly curved forms (brachylabic) to longer, straighter forms (macrolabic).
Unusual Parental Behavior
The European earwig is notable among insects for its parental care, which begins with the reproductive cycle in late summer and early fall. Following mating, the female excavates a subterranean nest where she and the male may initially hibernate together. She then lays a clutch of 30 to 55 elliptical, pale yellow eggs, after which she typically expels the male.
The mother remains with her eggs throughout the winter, suspending her own foraging activities to brood the clutch. This care involves constantly guarding the eggs against predators and regularly cleaning them. This cleaning prevents the growth of fungi and ensures the eggs’ survival until they hatch, which takes approximately 70 days in cool spring temperatures.
After the first instar nymphs hatch, the mother continues to guard and provide food for them for several weeks. The nymphs remain closely aggregated with the female, who defends and provisions them. The young nymphs begin to forage independently after their first molt, but they may still return to the maternal nest during the day.
Diet, Habitat, and Ecological Niche
The European earwig operates as an omnivore, consuming both plant and animal matter. This flexible feeding strategy positions it as both a beneficial insect and a garden pest, depending on the available food sources. Earwigs are opportunistic predators that consume a variety of soft-bodied insects, such as aphids, mites, insect eggs, and small caterpillars.
The predatory habits of the earwig contribute to natural pest control in gardens and orchards. However, their herbivorous tendencies can cause damage to certain plants and crops. They feed on tender plant parts, including young seedlings, flowers, soft fruits like strawberries and apricots, and the silks of sweet corn.
The earwig thrives in environments that offer dark, cool, and moist conditions, such as under stones, logs, leaf litter, and in crevices. This preference is tied to their nocturnal pattern; they hide during the day and emerge at night to feed. Earwigs also act as scavengers, feeding on decaying organic matter, lichens, and fungal spores, which aids in decomposition.
Managing Earwigs in the Home and Garden
Controlling earwigs effectively relies on integrated pest management, prioritizing non-chemical methods that modify their surrounding environment. Habitat modification is key, focusing on eliminating the dark, damp hiding places they seek during the day. This involves removing debris, wood piles, heavy ground covers, and leaf litter from around garden beds and the home’s foundation.
Reducing moisture is also a highly effective method, as earwigs are moisture-loving insects. Homeowners should ensure proper ventilation in crawl spaces, repair leaky faucets, and adjust irrigation to avoid overly wet soil surfaces. For managing indoor nuisance issues, the strategy shifts to exclusion, meaning sealing potential entry points into the home.
Simple non-chemical traps can actively reduce earwig populations in the garden.
- Rolled-up newspaper or short pieces of garden hose placed near plants act as attractive daytime shelters.
- These traps can be collected in the morning and the trapped earwigs shaken into a container of soapy water.
- Another popular trap involves sinking a low-sided can into the soil and filling it with vegetable oil.
- Adding a drop of fish oil or bacon grease to the oil attracts and drowns the insects.