Earwig Facts, Identification and Control
Scientific Order: Dermaptera
Forficulidae, including the most common earwig, the European Earwig (Forficula auricularia)
Size: Around 16 millimeters long (or ⅝ inches)
Color: Red-brown to dark brown with brighter, yellow-brown legs.
Diet and Behavior
Most species of earwig are omnivorous. They eat a wide variety of living and dead plant and animal material, including flowers, bushes, and hostas. Earwigs are considered a crop pest because they feed on seedlings, corn silk and ears, cauliflower heads, chard, and several other varieties of flowering crop plants.
Earwigs are nocturnal and sensitive to heat and dryness. They hide in dark, damp locations during the day and only become active at night. In dry environments or during hot seasons, earwigs have to seek out confined, dark, and wet locations, such as the inside of plant life or under potted plants, in order to survive.
Reproduction and Life Cycle
Adult earwigs reproduce sexually in the late summer or early fall. A fertilized female earwig excavates a special burrow 15mm deep, which she uses to store fertilized eggs. The female deposits 20-60 eggs in the burrow. Eggs take anywhere between 12 to 85 days depending on temperature.
Earwigs undergo four nymphal “instar” stages broken into two phases: nesting and free-foraging. First instar nymphs stay in the nest. Second instar nymphs venture out of the nest at night to seek food. Third and fourth instar nymphs become free-roaming, seeking food and shelter on the surface until adulthood.
Signs of Infestation
If you have a garden or ornamental plants, look for small bite marks on the leaves or flower buds. These bite marks may be circular on the inner part of a leaf or flower bud, or they may simply look like fraying on the outer edges.
Earwigs secrete a foul-smelling liquid when threatened or crushed, so if you have an unidentified smell outside or around your building, look for earwigs. The secreted liquid can also stain cloth and carpeting if left alone.
Treatment and Prevention
Practice regular lawn, yard, and lot maintenance. Reduce the natural debris earwigs can hide under to deprive them of places to stay out of the heat. Remove rotting or dying plants, fallen leaves, piles of lumber, and excess mulch. Look for ways to reduce the humidity around your building.
Minimize moisture and humidity both in and outside of your building. Keep an eye on your downspouts, gutters, and other irrigation systems to prevent water buildup after rain. Ventilate crawl spaces properly. Look for sources of moisture inside your building and correct them.
Earwigs have a large set of forceps-like pincers called cerci located on the tip of their abdomens (rear, opposite their heads). Earwigs use their cerci to hunt for food and defend themselves.
Most earwigs, including the European earwig, possess two sets of wings and are capable of limited flight. The name references these wings, which are shaped like a human ear when unfolded in flight.
Adult earwigs use their pincers defensively and will clamp down on humans if threatened, but they can’t generate enough force to hurt people.
University of Minnesota Field School for Agricultural Professionals’ European earwigs in homes and gardens fact sheet
Penn State University College of Agricultural Sciences Department of Entomology’s European Earwigs Insect Advice Fact Sheet
Cornell University Department of Entomology Earwig Insect Diagnostic Laboratory fact sheet