Definição e significado de silverfish

From Wikipedia, the free encyclopedia

Lepisma saccharina, frequently called silverfish, fishmoths, carpet sharks, or paramites, are small, wingless insects in the order Thysanura. They are typically between an inch and half an inch in length (12–25 mm). Its common name derives from the animal's silvery light grey and blue colour, combined with the fish-like appearance of its movements, while the scientific name indicates the silverfish's diet of carbohydrates such as sugar or starches.

Etymology

The scientific name for the species is Lepisma saccharina, due to its tendency to eat starchy foods high in carbohydrates and protein, such as dextrin.^[2] However, the insect's more common name comes from a combination of the words silver and fish, coming from the insect's distinctive metallic appearance and fish-like shape.^[3] While the scientific name can be traced back to 1758, the common name has been in use since 1855.^[4][5]

Description

Silverfish are nocturnal, elongate, and flattened insects typically between 1 inch (25 mm) and 0.5 inches (13 mm) in length.^[6] Their abdomen tapers at the end, giving them a fish-like appearance.^[7] They are born whitish, but develop a grayish hue and metallic shine as they get older.^[2] They have three long cerci at the tips of their abdomens, one parallel to their body, one facing left, and one facing right. They also have two small compound eyes, despite other members of Thysanura being completely eyeless, such as the family Nicoletiidae.^[7][8]

Like other species in Apterygota, silverfish completely lack wings.^[7][9] They have long antennae, and move in a wiggling motion that resembles the movement of a fish.^[10] This, coupled with their appearance, influences their common name. Silverfish typically live for two to eight years.^[2]

Diet

Silverfish consume matter that contains polysaccharides, such as starches and dextrin in adhesives.^[2] These include glue, book bindings, paper, photos, sugar, coffee, hair, carpet, clothing and dandruff. Silverfish can also cause damage to books and tapestries. Other substances that may be eaten include cotton, linen, silk and synthetic fibers, and dead insects or even its own exuvia (moulted exoskeleton). During famine, a silverfish may even attack leatherware and synthetic fabrics. Silverfish can live for a year or more without eating.^[2][6]

Distribution

Silverfish are a cosmopolitan species, found throughout North America, Europe, Australia, Japan, Asia, and other parts of the Pacific.^[11] They inhabit moist areas, requiring a relative humidity between 75% and 95%.^[12] In urban areas, they can be found in basements, bathrooms, garages, closets, and attics.^[2]

Reproduction and life cycle

The reproduction of silverfish is preceded by a ritual involving three phases, which may last over half an hour. In the first phase, the male and female stand face to face, their trembling antennae touching, then repeatedly back off and return to this position. In the second phase the male runs away and the female chases him. In the third phase the male and female stand side by side and head-to-tail, with the male vibrating his tail against the female.^[13] Finally the male lays a spermatophore, a sperm capsule covered in gossamer, which the female takes into her body via her ovipositor to fertilize the eggs.

The female lays groups of less than fifty eggs at once, deposited in small crevices.^[14] The eggs are oval-shaped, whitish, about ¹⁄₃₂ inches (0.079 cm) long,^[15] and take between two weeks and two months to hatch. Silverfish usually lay less than one hundred eggs in their lifetime.^[6]

When the nymphs hatch, they are whitish in color, and look like smaller adults. As they molt, young silverfish develop a grayish appearance and a metallic shine, eventually becoming adults after three months to three years.^[14] They may go through seventeen to sixty-six molts in their lifetime, sometimes thirty in a single year, much more than usual for an insect. Silverfish are one of the rare species of insect that continue to molt after mating.^[16]

Relationship with humans

Silverfish are considered a household pest, due to their consumption and destruction of property.^[6] While responsible for the contamination of food and other types of damage, they do not transmit disease.^[2][17]

Predation

Earwigs, house centipedes, and (in rare cases) spiders are known to be predators of silverfish.^[18][19]

References

External links

• Klass, Carolyn (11/1981; updated 12/2008). "Silverfish and Firebrats". Cornell University. http://www.entomology.cornell.edu/public/IthacaCampus/ExtOutreach/DiagnosticLab/Factsheets/SilverfishFirebrats.html. Retrieved 2008-12-25.  At Cornell Cooperative Extension, Insect Diagnostics Laboratory
• "Magnified pictures of Silverfish". Mount Allison University. http://www.mta.ca/dmf/silverfish.htm. Retrieved 2008-12-25.