Ctenolepisma lineatum

Distinguished from Lepisma saccharina (common silverfish) by its stouter, less shiny body and proportionally longer appendages. The dark brown lines on the abdomen are often visible and provide a quick diagnostic feature, though these may be faint or absent in some individuals. Distinguished from Thermobia domestica (firebrat) by habitat preference—C. lineatum tolerates a wider range of humidity conditions and is found both indoors and outdoors, whereas firebrats prefer consistently warm, dry environments. Distinguished from Ctenolepisma longicaudata by body proportions and line patterns. Specimens with broken caudal filaments may be confused with other silverfish species; intact specimens with all three filaments present are more readily identified.

Body stouter and less shiny than Lepisma saccharina. Antennae and three caudal filaments (the two lateral cerci and median caudal filament) are noticeably longer relative to body size. Abdomen often marked with dark brown longitudinal lines. Body covered in short hairs and scales that create a slippery texture. Length ranges 8–15 mm excluding appendages. Coloration generally duller than the common silverfish.

Found in both indoor and outdoor environments. Indoors, occupies nooks, crevices, and undisturbed areas with moderate humidity. Outdoors, occurs in ground litter, under stones, bark, and other sheltered microhabitats. Tolerates a broader range of humidity conditions than the firebrat, though generally prefers more humid situations than that species. Not restricted to artificially heated environments.

Native to southern Europe. Introduced globally through human commerce and now established throughout most of the world except polar regions and cooler temperate zones such as the British Isles. Present in North America, including the United States and Canada, as well as other continents with suitable climates.

Active year-round in suitable environments. Being a household pest in temperate regions, adult and immature stages may be encountered in any season. No specific seasonal emergence pattern documented; continuous breeding likely in favorable indoor conditions.

Feeds on carbohydrates, with particular preference for starchy materials. Known to consume bookbinding paste, wallpaper paste, starch in clothing (especially silk and rayon), oatmeal, damp wheat flour, cereals, and other stored organic materials. Scavenges opportunistically on various debris.

Undergoes incomplete metamorphosis (ametabolous development). Young resemble adults but are smaller and not sexually mature. Molts repeatedly throughout life—laboratory specimens have been observed molting over 40 times during a lifespan of at least 2.5 years. Adults continue to molt after reaching sexual maturity. Eggs laid singly or in small batches in cracks and crevices. Sperm transfer via spermatophores deposited by males; males spin silk strands from mouthpart glands to loosely restrain females during sperm transfer. Lifespan at least 2 years under laboratory conditions.

Nocturnal, hiding in crevices during daylight hours. Capable of rapid running when startled, nearly as fast as cockroaches. Molting continues throughout life, possibly to replace scales lost during movement through tight spaces or predator encounters. Males deposit spermatophores and use silk to loosely bind females during mating.

Scavenger that contributes to decomposition of starchy organic materials. Serves as prey for various predators including house centipedes and spiders. Part of the anthropogenic ecosystem in human dwellings.

Considered a nuisance pest in homes, libraries, warehouses, and storage facilities. Damage to books, wallpaper, clothing, and stored food products can occur, though populations rarely reach levels causing significant economic impact. Control methods include reducing humidity, removing food sources, and chemical treatments when necessary.

• Lepisma saccharinaCommon silverfish has shinier, more slender body with proportionally shorter antennae and caudal filaments; lacks distinct dark abdominal lines
• Thermobia domesticaFirebrat prefers hot, dry environments such as around furnaces and heating pipes; has more uniform coloration without distinct abdominal lines
• Ctenolepisma longicaudataDistinguished by body proportions and abdominal line patterns; often requires microscopic examination for definitive separation

• BugGuide
• Wikipedia
• iNaturalist taxon
• NCBI Taxonomy
• Bug Eric: Silverfish and Firebrat
• Researchers Find Hundreds of Arthropod Species in U.S. Homes
• Cerambycidae | Beetles In The Bush | Page 8