The insects of the order Thysanura, usually referred to as silverfish, may also be called bristletails, from their three long caudal filaments. The families Machilidae and Meinertellidae of the jumping bristletails were once included with Thysanura, but are now in the order Archaeognatha (= "Microcoryphia").
Occasionally, the correspondingly restricted order Thysanura is referred to as Zygentoma.
Silverfish are so called due to the silvery glitter of the scales covering their bodies. Their movement is "fish-like" and makes it look as if they're swimming. They are less than half an inch (1 cm) long and found in damp corners or amongst books and paper in houses. Silverfish feed on cereals, paste, paper, starch in clothes, rayon fabrics and dried meats. Silverfish can sometimes be found in bathtubs or sinks at night, as they have difficulty moving on smooth surfaces and so become trapped. Wild species often are found in habitats such as caves, and some are commensals living in association with ant colonies.
There are no current species formally considered to be at conservation risk, though several are troglobites limited to one or a few caves or cave systems, and these species run an exceptionally high risk of extinction.
Lepismatidae is the largest family, widespread with more than 200 species, many living in human habitations. The Nicoletiidae are small and live in soil litter, humus and under stones. The Lepidothrichidae are represented by two species Lepidothrix pilifera
from Baltic Amber and Tricholepidion gertschi
from forests of northern California. Three species of Maindroniidae are found in the Middle East and in Chile. The Ateluridae live in nests of ants and termites and are small and blind.
Silverfish have an elaborate courtship ritual to ensure exchange of sperm. The male spins a silken thread between the substrate and a vertical object. He deposits a sperm packet (spermatophore
) beneath this thread and then coaxes a female to walk under the thread. When her cerci
contact the silk thread, she picks up the spermatophore with her genital opening. Sperm are released into her reproductive system, and then she ejects the empty spermatophore and eats it.
- Grimaldi, D. and Engel, M.S. (2005). Evolution of the Insects. Cambridge University Press. ISBN 0-521-82149-5.
- Charles A. Triplehorn and Norman F. Johnson, Borror and DeLong's Introduction to the Study of Insects, 7th edition (Thomas Brooks/Cole, 2005), pp. 177-180
- Firefly Encyclopedia of Insects and Spiders, edited by Christopher O'Toole, ISBN 1-55297-612-2, 2002