Earwigs (Dermaptera) are common nocturnal insects found across the globe, inhabiting a wide range of environments, from gardens and fields to forests and occasionally human dwellings. Understanding the earwig’s diet is complex because their feeding habits are diverse. This flexibility means they can act as beneficial scavengers, garden pests, or predators, depending on the food sources available.
The Primary Diet: Omnivores and Scavengers
Earwigs are omnivores, meaning their diet incorporates both plant and animal matter. A significant portion of their diet consists of dead or decaying organic material, establishing them as decomposers in many ecosystems. They actively scavenge on rotting wood, fungi, mold, and various types of decaying plant debris, such as leaf litter and compost.
When preferred food is scarce, these insects consume algae and lichens, utilizing a wide spectrum of available resources. Consuming this decaying matter helps break down organic material, recycling nutrients back into the soil. This scavenger role often takes precedence over other feeding behaviors, especially when conditions are moist and dark, which are the habitats they prefer.
Earwigs as Garden and Household Pests
Despite their role as decomposers, earwigs readily switch to consuming plant tissue. They target soft, tender parts of plants, including new seedlings, flower petals, and developing fruits. Specific garden favorites include corn silk, lettuce, strawberries, and ornamental flowers like dahlias and marigolds.
The damage they leave is distinctive, appearing as irregular holes or ragged edges on leaves, often concentrated near the midrib or veins. When they infest fruits like apricots or peaches, they may chew shallow gouges or bore holes into the flesh. Earwigs sometimes venture indoors seeking shelter or moisture, where they scavenge on dropped starchy foods, grease, or unsecured pet food.
Predatory Behavior
Beyond scavenging and plant feeding, earwigs also function as predators. They use their strong abdominal pincers not only for defense but also to capture and hold small, soft-bodied prey. This predatory behavior is beneficial in a garden setting because they target common pests.
Their prey includes aphids, mites, scale insects, and the eggs and larvae of various other arthropods. A single earwig can consume significant numbers of aphids, helping to control pest populations. Earwigs also exhibit cannibalism, consuming their own eggs or weaker nymphs when other food sources become severely limited.