Earwigs belong to the insect order Dermaptera, easily identified by the prominent, forceps-like appendages, called cerci, extending from the rear of their abdomen. These insects are found globally and are recognized by their flattened, elongated bodies, typically ranging from a quarter-inch to one inch in length. Despite their common name, earwigs do not seek out human ears to enter or burrow. They are not attracted to people and prefer dark, damp outdoor environments.
Habitat and Nocturnal Activity
Earwigs prefer environments that are consistently dark, damp, and sheltered, which helps them avoid desiccation. They are often found hiding beneath rocks, logs, boards, or in the moist environment of leaf litter and mulch. This preference for tight, moisture-rich crevices can lead them to invade homes, particularly basements, bathrooms, and kitchens, when outdoor conditions become too dry or hot.
Their activity is primarily nocturnal; they spend daylight hours concealed and emerge after dark to forage. When disturbed from their hiding spots, earwigs rapidly move to find a new, tight crevice. This scramble to conceal themselves is linked to their need to maintain body moisture.
This nighttime activity pattern makes them common garden inhabitants rarely seen during the day. They navigate the environment searching for food and mates under the cover of darkness. Some species are attracted to outdoor lights, which can inadvertently draw them closer to homes and structures.
Dietary Habits and Ecological Impact
Earwigs are considered omnivores and scavengers, possessing a variable diet that allows them to thrive. They consume a wide variety of materials, including decaying organic matter (detritus), fungi, algae, and small arthropods. This scavenging role is beneficial, as they contribute to the breakdown of decaying material, helping recycle nutrients back into the soil.
Their feeding habits, however, also cause them to be seen as pests in agricultural and garden settings. They consume tender plant tissues, including flowers, soft fruits, vegetables, and young seedlings, leaving behind irregular holes in leaves and petals. This herbivorous feeding can result in damage to crops and plants, particularly when populations are large.
Their role as predators benefits integrated pest management strategies. Earwigs actively hunt and consume small, soft-bodied garden pests such as aphids, mites, caterpillars, and insect eggs. Some studies suggest that earwigs can significantly reduce aphid populations, showcasing their utility as a natural biological control agent.
The ecological impact of the earwig is context-dependent, shifting between beneficial decomposer and pest. Management often involves balancing their predatory benefits against the potential for plant damage. This dual role means they are a natural part of the ecosystem, especially in areas with abundant moisture and organic debris.
The Unique Lifecycle of the Earwig
The earwig lifecycle is characterized by incomplete metamorphosis, developing through three stages: egg, nymph, and adult. Mating typically occurs in the autumn, with the female preparing a subterranean nest chamber in the soil or under debris. A female usually lays between 20 to 60 eggs in this prepared cell, though some species may lay up to 90.
A distinctive behavior of the female earwig is the maternal care she provides, a trait uncommon among insects. The mother remains with her brood, actively guarding the eggs from predators and even her own mate. She also periodically cleans the eggs by licking them, a behavior thought to prevent the growth of harmful fungi and mold.
If environmental conditions change, the female will move the eggs to a more suitable location, demonstrating a dedicated investment in the survival of her offspring. Once the eggs hatch, the young earwigs, called nymphs, resemble smaller versions of the adults but lack full development of wings and pincers.
The mother continues to care for the nymphs through their first molt, protecting them and sometimes opening the nest passageway for them to forage at night. After a few molts, the nymphs become more independent, dispersing from the nest to forage freely and eventually reaching adulthood after about four to six molts.