What kind of insect is the late summer kigo 'Silverfish'?
Introduction
Hello! This is 'Yamato no Mushiya' (The Yamato Bug Shop).
August is almost over; I wonder if all the students are busy with their summer vacation homework? Looking at haiku seasonal words, this period (mid-August to early September) is considered 'late summer.' I happened to find the name of an insect called 'Silverfish' (shimi) as a late summer seasonal word, and I felt a strange sense of destiny.
So, today I'm going to talk about the insect known as the silverfish!
Did you know? This is what a silverfish is like!
You might know the name 'silverfish,' but many people may not know what kind of insect it actually is. In Japanese, it is written with the characters for 'paper' and 'fish,' and unusually, it does not contain the character for 'insect' or the insect radical. However, it is a bona fide insect.
Silverfish are small insects about 1 cm long, with a slender, oval shape that looks like an elongated teardrop. They are characterized by two antennae on their head and three long, tail-like appendages on their rear. Their entire body is covered in silvery scales, giving them a dull, metallic luster.
In English, they are called 'silverfish.' They are named after fish in both languages because their movement is wriggly, just like a swimming fish. From my perspective, though, they look like insects no matter how you slice it (laughs).
Surprising ecology, and their true nature!
The most unique aspect of the silverfish's ecology is that it is 'ametabolous.' Insect metamorphosis involves molting and changing form, but most insects undergo either 'complete metamorphosis' (like butterflies or beetles, which become pupae) or 'incomplete metamorphosis' (like grasshoppers or cockroaches, which change form without becoming pupae).
However, silverfish just get bigger when they molt; their appearance does not change at all. It is said that only silverfish and bristletails, which are very primitive insects, undergo this ametabolous development.
Silverfish are surprisingly long-lived, with some living for as long as 7 to 8 years. While they have a strong image of eating paper, they are actually omnivorous and will eat anything, including human food crumbs, hair, and the carcasses of other insects. They can survive without food, but they need moisture, so they prefer humid places.
Are they harmful?
Silverfish are treated as 'pests,' but in my personal opinion, they don't cause that much damage. First of all, they rarely swarm like other insects. While they do eat paper, they tend to nibble and scrape at it, so unless the situation is very severe, they rarely leave holes in books. If you see holes in a book, it might be the work of a different insect.
Even if I see a silverfish in my house, I don't kill it; I just watch over it quietly.
What should you do if you find a silverfish?
To get rid of silverfish in your home, it is important to 'eliminate their habitat,' 'eliminate their food source,' and 'keep things dry,' just as you would with other pests.
Silverfish love to hide in humid places, especially in gaps where books and cardboard boxes are piled up. Therefore, ventilating your room frequently or cleaning the back of your bookshelves can be effective. As a measure specific to silverfish, airing out your books is also recommended.
If you really want to exterminate them, they are slow-moving, so you can crush them with a tissue, and insecticides are also very effective.
Summary
At first glance, the silverfish has a plain and mysterious appearance, but its ecology is very profound.
Just because they eat paper, there is no need to be overly afraid of them. By eliminating the environment they prefer, you can maintain a comfortable living space. If you find one in your house, it might be interesting to try observing it first!
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