Earwigs and silverfish are entirely different insects often confused due to their similar size and tendency to invade homes. While both are small, dark-loving pests, they belong to separate taxonomic orders, with earwigs being part of Dermaptera and silverfish belonging to Zygentoma. This distinction means they possess unique physical traits, follow completely different diets, and have separate habitat preferences. Understanding these differences is the first step in identifying which insect is present.
Distinct Physical Characteristics
The most reliable way to differentiate these two insects is by observing their rear appendages. Earwigs are instantly recognizable by the prominent pair of forceps, or cerci, that extend from their abdomen. These pincer-like structures are used for defense, capturing prey, and folding their wings. Earwigs have a dark, reddish-brown, elongated, and flattened body, usually measuring between 0.5 to 1 inch in length.
Silverfish, conversely, are defined by three long, thin, tail-like filaments that protrude from their rear. They have a distinct teardrop or carrot-shaped body that tapers from head to tail, covered in fine, silvery scales that give them their name. Silverfish are wingless, and their movement is characterized by a unique, wiggling motion that resembles a fish swimming. Unlike earwigs, silverfish are incapable of flight.
Preferred Habitats and Diets
Earwigs are primarily outdoor inhabitants that prefer cool, dark, and damp environments rich in decaying organic matter. Their main outdoor habitats include mulch, leaf litter, compost piles, and under stones or wood near the foundation of a home. As omnivorous scavengers, their diet consists mainly of dead insects, aphids, soft fruits, and plant matter. They typically move indoors only as “occasional invaders” when outdoor conditions become too dry or wet, seeking temporary refuge in basements or crawl spaces.
Silverfish are true indoor pests that require high humidity, thriving in relative humidity levels of 75% to 95%. They are commonly found in humid areas of a structure, such as bathrooms, basements, attics, and kitchens, often hiding in cracks and crevices near water sources. Their diet is highly specific, targeting materials high in starches, sugars, and protein, which includes paper products, book bindings, wallpaper glue, dried foods, and certain synthetic fabrics.
Addressing Common Concerns
Neither earwigs nor silverfish are considered a physical threat to human health, as they are not known to bite people or transmit diseases. The earwig’s cerci, while intimidating, are used for defense and are generally too weak to break human skin. The common myth that earwigs crawl into human ears is unfounded folklore.
The main concern with these insects is the potential for property damage, which differs significantly between the two. Earwigs are mostly garden pests that cause minimal structural damage indoors, primarily becoming a nuisance when they cluster in damp areas. Silverfish, however, pose a greater threat to household items due to their diet of starches and cellulose. They can cause irreparable damage to important documents, books, wallpaper, and clothing by scraping away the material to feed.