Ctenolepisma longicaudatum

Ctenolepisma longicaudatum, generally known as the gray silverfish, long-tailed silverfish or paper silverfish, is a species of Zygentoma in the family Lepismatidae. It was described by the German entomologist Karl Leopold Escherich in 1905 based on specimens collected in South Africa, but is found worldwide as synanthrope in human housings. In recent years, gray silverfish have increasingly become an issue in indoor environments in Europe, especially in newly built houses with a stable climate beneficial for the growth and reproduction of this species. As a food generalist with the ability to digest the cellulose contained in paper and cellulose-based textiles like rayon, Ctenolepisma longicaudatum is considered a pest species in cultural heritage institutions like libraries and archives. Most authors have historically treated the nomenclatural gender of Ctenolepisma as feminine, but in 2018 the International Commission on Zoological Nomenclature issued a formal ruling (ICZN Opinion 2427) stating the gender of Lepisma (and all genera with that ending) is neuter, following ICZN Article 30, which resulted in changes to the spelling of several well-known species, including Ctenolepisma longicaudatum (formerly longicaudata). The nymphs and adults are slender, agile, fast-moving insects with long, paired antennae and three long appendages at the posterior abdomen: a pair of cerci and the single central epiproct. Apart from the earlies instars, the body is covered with scales, giving the light- to dark greyish animals a glimmering appearance. With their brushes and bristles along the body sides, gray silverfish somewhat resemble the related firebrats. The eyes consist of twelve stemmata, which are rather more rounded in early instars. The eggs have an oval shape with dimensions of about 1.15 x 0.83 mm. Two to twenty eggs are laid per lot, and they are normally deposited about 2 mm into crevices or cracks, or under the edge of paper. Freshly laid eggs are smooth and cream-coloured; after three days the chorion turns yellow and exhibits shallow reticulate markings.