It sometimes happens to find the so-called silver fish (Lepisma saccharina) in the books in our libraries at home. This insect completely harmless it is a regular resident of many homes, especially in damp and dark environments. It is called a silverfish due to its rapid movements and its oblong, silvery appearance which actually resembles the appearance of a miniature fish. The scientific name of the species “saccharina” it is instead motivated by the fact that this insect feeds on substances containing sugars, such as starch and cellulose.
What are silverfish and why do they hide in the house
The Silverfish (Lepisma saccharina) has an elongated body covered with microscales silvery, like a real fish, and is equipped with a pair of long antennas on the head and three thin terminal appendages (cerci) used for a tactile function. It has no wings (apterous) since it is a very ancient insect from an evolutionary and rather primitive point of view.
It belongs to the Order of Zygentomes, known in the past as Thysanuri and which appeared on Earth approximately 300 million years ago. Precisely because they are not very evolved, silverfish do not undergo metamorphosis during development (in technical jargon they are said to be ametabolous) and they emerge from the eggs with the same appearance as the adultsbut smaller in size. During the course of their lives they undergo numerous molts both during growth and as adults: they can molt up to 70 times being quite long-lived.
They are insects cosmopolitans present all over the world, in nature they live under stones, between cracks in rocks or in leaf litter and feed on plant debris rich in cellulose or of starchfrom which the scientific name of the species derives “saccharina”. We often find them at home because it is a more than ideal environment for them: in fact they prefer warm and humid places (from 75 to 95% humidity) and are lovers of paper and cardboard, as well as being able to feed on linen, cotton or book glue. It is no coincidence that we find them mainly in home and public libraries: books are a source of food for them. As adults they last a long time even without feeding. They move mainly at night, finding refuge during the day behind furniture, under plant pots or between the pages of the books they feed on.
Their bitter enemies are the scutigera (Scutigera coleoptrata) and the so-called spitting spider (Scytodes thoracica) which feeds on silverfish by “spitting” a liquid on its prey which, upon contact with air, solidifies and paralyzes the insect.
Harmless to humans, but harmful to books: methods to remove it
The silverfish is absolutely harmless if it weren’t for the damage it can cause to books and documents: this is why its proliferation is feared in libraries and museums. It does not bite, it does not sting and it is not poisonous; it can, at most, trigger allergic reactions in predisposed subjects.
If the damage to paper and fabric becomes extensive, However, it is not easy to get rid of this agile insect; their flattened body, nocturnal habits and rapid movements make them difficult to intercept. Some substances keep them away: Japanese cedar essential oil seems to be a good repellent, as well as boric acid and pyrethrin are very effective. It would still be necessary to contain them reduced humidity in the roomsusing dehumidifiers and spaces should be kept clean by vacuuming floors and carpets, as well as sealing skirting boards and cracks in the home.
