The four-lined silverfish (Ctenolepisma lineata)
Zygentoma: Lepismatidae: Ctenolepisma lineata (=quadriseriata) (Fabricius, 1775)
This week’s insect, the four-lined silverfish (Ctenolepisma lineata), is a familiar insect to many since it often lives in domestic situations. Silverfish represent one of the oldest lineages of true insects (“true insects” meaning all but the basal entognathous groups of hexapods), being about 400,000,000 years old! As old as they are, they are little changed from their ancestors, appearing today to be “primitive” (some groups even have styli on the underneath of their abdomens, similar to extra legs). While Ctenolepisma lineata is not necessarily a native of NC (it is originally from Europe), it has been here for a very long time and, thus, can be considered established.
The four-lined silverfish is larger (12-19mm) than its close relatives the common silverfish (Lepisma saccharina) and the firebrat (Thermobia domestica), and differs from Ctenolepisma longicaudata in having a striped appearance. Silverfish get their names from the iridescent scales covering the body (see below); some are more silvery than others, and Ctenolepisma longicaudata is more of a beige + silver.
A close-up of Ctenolepisma lineata showing the scaly body.
Silverfish are truly scavengers: they mainly eat carbohydrates/starches, but will also consume book bindings, wallpaper glue, paper, photos, sugar, coffee, hair, carpet, clothing, dandruff, cotton, linen, silk, synthetic fibers, dead insects, exuviae (shed skins), and even leather. Because of this, silverfish that invade homes can sometimes be pests, destroying tapestries, books and clothing, among other things. Silverfish appear to be able to digest cellulose without the aid of gut flora, probably using enzymes that they produce themselves (Lasker & Giese, 1956). Biologically, silverfish can take months to years to reach sexual maturity, and are one of the few groups of insects that continues to molt after becoming an adult. They also change little in appearance from young to adult, referred to in insects as ametamorphosis.
Specimens in the NCSU Insect Museum: We only have a handful of silverfish determined as Ctenolepisma lineata in the museum’s alcohol collection (80% ethanol being the medium to preserve these soft-bodied insects). They were collected from Wake and Chatham Co. houses in the mid-1980s.
Find out more:
Wygodzinsky, P. 1972. A Review of the Silverfish (Lepismatidae, Thysanura) of the United States and the Caribbean Area. American Museum Novitates. 2481. [PDF]
University of Missouri Extension Pest Guide to Silverfish [PDF]
Zygentoma records on GBIF (only 1 in North America): http://data.gbif.org/species/13141220