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How do silverfish grow without undergoing major changes in body form?

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Illustration showing a variety of adult insects, each labeled with its common name and order, including walkingstick, earwig, stonefly, tree cricket, dragonfly, female scale, cat flea, thrips, sucking louse, thysanuran, ant, scarab beetle, stinkbug, mosquito, and cabbage butterfly, highlighting their diverse shapes and sizes. — insect An illustration of insect diversity.

Silverfish grow through a process known as ametabolous development, which is characteristic of primitive, wingless insects (apterygotes). Unlike insects that undergo dramatic transformations, silverfish experience almost no change in body form as they mature.12

Instead of a complex metamorphosis, silverfish simply undergo a gradual increase in size until they reach adult dimensions. This growth is facilitated by molting—the periodic shedding of their outer skeleton. When they hatch, the young are already similar to adults, though they are initially scaleless with shorter appendages. Through a series of molts, they gradually acquire adult features.23

Notably, silverfish continue to molt throughout their entire lives, even after reaching sexual maturity, sometimes molting dozens of times over the course of several years.34