Lepisma saccharina (Linnaeus, 1758)

Synonym(s) : 

Lepisma vulgaris Scopoli 1763

Common names

  • Petit poisson d’argent Lépisme Lépisme argenté Lépisme du sucre.
  • Silverfish wood fish paper moth fish moth silver witch.
  • El pececillo de plata
  • Silberfischchen

Classification:

  • Order:  Zygentoma
  • Family:  Lepismatidae
  • Genus:  Lepisma
  • Species:  saccharina

Frequency index:

5
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Overview

Lepisma saccharina or silverfish are mainly found in diverse damp places (warehouses, industrial tenements, bakeries, kitchens, bathrooms, cellars, attics…). They sometimes abound in archive premises and libraries where they can cause severe damage. Their food diet is polyphagous. The species is easily recognisable thanks to its body covered in silvery scales. They have 3 filaments or cerci of unequal length at the rear of their abdomen. They are considered as primitive animals (they are more than 400 million years old). They first appeared long before insects became able to fly. Silverfish hate light. They are fearful creatures that very quickly run away for shelter; they can even move sideways. They have a nocturnal activity and prefer places where temperatures range between 22° and 27°C, with 75 to 97% optimal humidity rate. They mostly feed at night and can survive several-week-long fasting periods. Their movements are very quick, their global shape and colour earned them the nickname Silverfish. They have a few natural enemies, mainly spiders and ants. 

Recognition criteria

Adult

Size   

7 to 12 mm long.


Aspect  

Wingless insects. Fusiform (spindle-shaped) body, wider at the front and getting narrower toward the rear end.
Antennae are the same length as the body.
Abdomen ending in 3 cerci half the body-length and of unequal length, the middle one being the longest.
Scales covering the whole body, giving them their characteristic silvery colour; the scales can sometimes peel off to enable the insects to free themselves from a spider’s web or from a predator’s grasp. 


Colour   

Entirely silvery metallic grey.

 

Larva

Size   

5 to 7 mm long.


Aspect    

Look very much like adults, but smaller.


Colour

Whitish.

Development cycle

Silverfish mostly reproduce themselves by parthenogenesis. Fecundation is preceded by a kind of seduction dance that can last half-an-hour and is composed of 3 phases.
After fecundation, females lay oval eggs, usually in micro-shelters (cracks…).
Fecundity ranges between about 20 eggs and several hundred; the egg-laying period stretches over several weeks, at a rate of between 1 and 3 eggs per day. The incubation period is fairly long: it can last up to 6 months and it depends on ambient temperature and hygrometry.
Silverfish are ametabolic insects : larvae look like adults, but they have to await the adult stage to reproduce. To that end, they undergo several molts (up to 80). Once they are adults and they have reached sexual maturity, silverfish can undergo a few more molts, which hardly ever happens in insects. The silvery scales that cover the body only appear after the third imaginal molt, sometimes later. Reaching the adult stage can take between 2 and 36 months.
Adults live 2 or 3 years, exceptionally up to 8 years, which also seldom happens in insects. 

Infected materials

Silverfish are polyphagous insects that develop at the expense of book-bindings, archives, all paper bases and starch bases (especially glossy ones with a synthetic base), fabrics, leather (in case of food shortage), silk, and any object containing paper or wallpaper paste.
They also feed on cotton, linen, silk, rayon, cellulose, pasta, vegetables, dried meat, oat flakes, flour, sugar, moults, microscopic fungi.
They can easily digest cellulose thanks to their crop and certain fabrics thanks to the bacteria in their digestive tract.
Silverfish presence can be detected thanks to the tiny, irregular, lace-like holes that they leave on paper and cardboard bases. Their presence can also be revealed by the small impregnations or yellowish traces they leave on infested fabrics.

Geographical distribution

Lepisma saccharina are believed to originally come from Asia. They are now distributed worldwide and are particularly common in tropical regions.