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Latin: Ctenolepisma longicaudata
In recent years, long-tailed silverfish (ctenolepisma longicaudata) have been registered more and more frequently in the household. Long-tailed silverfish is related to the well-known silverfish, but as an adult is larger, has long tail wires and antennae as well as a clearer hair. There is also a big difference in how the two species behave in buildings.
This is what long-tailed silverfish look like
The long-tailed silverfish is a wingless insect that grows 15-19 mm long. As an adult, the long-tailed silverfish is squinted and dark gray, but as a nymph, and not a sexually mature insect, it is somewhat lighter in color, as these have no squints.
The body shape is very similar to an ordinary silverfish, but the long-tailed silverfish is somewhat larger. In the end, the long-tailed silverfish has three characteristic tail strands that can be longer than the body itself. The tail wires can be positioned up to 90 degrees from the middle tail wire. The front beard has two antennae. Both tail wires and antennae can easily break and you often experience individuals who deviate from the normal. Ordinary silverfish also have two antennae in front and three tail wires. However, the silverfish’s tail threads are far from as distinctive as those of the long-tailed silverfish, and they are at most half as long as the body itself.
As mentioned, an adult long-tailed silverfish will be 15-19 mm long, while the nymphs are 2 mm when the egg hatches.
Difference between long-tailed silverfish and silverfish
There are very clear differences between long-tailed silverfish and silverfish when both are adults. However, it can be difficult to distinguish between long-tailed silverfish in the nymph stage and common silverfish. Here, their behavior and the way they behave in buildings can help determine whether it is long-tailed silverfish or silverfish.
Silverfish live only in humid environments with a humidity of 75-97% RH. Therefore, you usually only experience silverfish in bathrooms and kitchens where there is a higher humidity than in the rest of your home.
Long-tailed silverfish are not similarly dependent on moisture and can therefore spread to the entire home without any problems. However, the nymphs live best at a humidity of 55-80% RH.
Beyond this, silverfish cannot climb on vertical surfaces; it can beard. If you look at the animals on vertical surfaces, there is therefore no doubt that they are long-tailed silverfish and not silverfish.
For a secure identification, one should combine several factors about the observed insects. How far is the insect? Can the insect climb on vertical surfaces? Where is the insect observed in the home?
Biology, life cycle and behavior of long-tailed silverfish
You can experience long-tailed silverfish in your home all year round. They eat both plant material and animal material. It does not take much food to keep a stock alive, even small amounts of flour, leftovers, crumbs, dead insects, dry leaves or other organic material may be enough. Long-tailed silverfish are even able to eat paper and wallpaper. Adult individuals can live up to 9 months while consuming nourishment.
The long-tailed silverfish goes through several stages from egg to adult. The life cycle is long and the hatching time of an egg, under optimal conditions, is approx. Two months. The long-tailed silverfish places its eggs in cracks and crevices where the eggs lie in safety. They are placed individually or in small groups. The eggs are light and about 1mm in diameter.
When the egg hatches, the nymphs are 2 mm long. They have no borders and are therefore lighter in color. The further development from the nymph stage to the sexually mature adult usually extends up to 2.5 – 3 years. After sexual maturation, the adult individuals can live for 3-4 years. They lay up to 200 eggs in their lifetime.
Long-tailed silverfish are nocturnal and thrive in dark places. Many people therefore see them in the morning when you turn on the light. After this, the long-tailed silverfish disappear either under floor panels or other cracks and crevices where they recur as long as it is light. The problem of long-tailed silverfish is therefore more prominent in the dark winter months, when the number of hours of natural light is limited.
Temperature effect in long-tailed silverfish
Both adult individuals and nymphs are sensitive to high and low temperatures. There is some uncertainty about the optimal temperatures for long-tailed silverfish, but several places state that they thrive best at temperatures between 17 ° C and 30 ° C. If the temperatures get much lower than this, it will significantly extend the life cycle of the long-tailed silverfish. Low temperatures will mean a low activity of long-tailed silverfish, but this does not mean that one has got rid of the problem.
Injuries to long-tailed silverfish
Museum effects, books and stamp collections can be particularly vulnerable if a population of long-tailed silverfish is allowed to develop and is not treated.
A small population of long-tailed silverfish will often not do much damage, but if the problem develops, the insects will be able to do damage to textiles and stationery.
You can experience that the long-tailed silverfish go in food in your kitchen cabinets and therefore also experience that they crawl around on the kitchen table. Most people find the long-tailed silverfish very annoying and uncomfortable to have in the home.
Control of long-tailed silverfish
Long-tailed silverfish are shady and are therefore nocturnal, which is one of the reasons why long-tailed silverfish are often only discovered when the problem has grown large enough to catch one’s attention. It is therefore important that you intervene quickly as soon as you discover that you have a long-tailed silverfish. A quick start-up of control can make it easier to get rid of the unwanted critters.
For effective control of long-tailed silverfish, it is important to locate their habitats. This can be done, for example, with insect traps that are placed in different places in the home to determine where the problem is greatest. At the same time, you can start with either spray treatment or application of toxins along floor panels as well as cracks and fissures in the home, as it is often here that the little critters hide.
Whether you are treating with pesticide or poison, thoroughness is a key word when dealing with long-tailed silverfish. The most effective remedies for long-tailed silverfish are often reserved for professional use and it may therefore be a good idea to contact a professional pest controller if you have got long-tailed silverfish in your home.
Control of long-tailed silverfish with pesticides
If you choose to treat with pesticides, it is important that you check your home for bearded cattle prior to treatment. You should inspect kitchen cabinets and drawers, wardrobes, bookshelves and the like.
Spray treatment of long-tailed silverfish must be carried out as a spot treatment in the places where the long-tailed silverfish live. It is especially along floor panels and in dark places like in cupboards and drawers. In addition, one should treat at pipe penetrations, so that barrier belts are made between, for example, apartments.
Control of long-tailed silverfish with poison
If you choose to treat with poison, it is equally important that you check your home for bearded prey before treatment. Edible poison is laid out in small gel drops under the floor panels at 1-2 meter intervals. In addition, small drops of poison should be placed in cracks and crevices and in dark places where long-tailed silverfish can reside.
Good advice against long-tailed silverfish
Some good advice to avoid getting long-tailed silverfish into your home is to keep an eye on the things you buy and bring into your home. Clothes that have been on holiday must be washed in a washing machine, groceries and packages you receive should be checked before you bring them into the home.
If you have already got long-tailed silverfish in your home – it can be difficult to solve the problem yourself. One can try insect traps and vacuuming, but it is rarely effective. Another good idea is to eliminate their hiding places. For example, it is a good idea to grout under floor panels, as long-tailed silverfish often hide here. One last piece of good advice, which can be difficult in practice, is to keep the home dry and cool. Beard cress optimal living conditions are at 17-30 degrees and at a humidity between 55% and 80% RH.