Miraculous transformation: how do caterpillars become butterflies? (5 photos)

The patterns on the wings of some butterflies resemble eyes. In this unusual way, insects protect themselves from birds of prey in a difficult battle for survival. In 2021, scientists saw for the first time how butterfly scales form inside a pupa. The transformation of a small crawling insect into an airy fairy is a perfect metaphor for change and improvement.





For this reason, scientists call the transformation metamorphosis, which in Greek means “transformation” or “change of form.” But not all caterpillars become fluttering insects. Although caterpillars go through the same four stages - egg, larva, pupa and adult - each stage has a different purpose and duration. The monarch butterfly, for example, changes completely in about one month. Evolution is inventive, isn't it?

Butterflies and metamorphoses

There are about 200,000 species of butterflies in the world. Their wings, which we admire so much, are made of flattened hairs called scales. The body of these beautiful insects is protected by a hard chitinous shell and wings. The butterfly's head has a rounded shape with a slightly flattened occipital part; it is inactive and connected to the chest.

Scientists distinguish two types of insect metamorphosis: complete and incomplete. Incomplete metamorphosis occurs when the young insect looks like a smaller version of the adult. This type of metamorphosis is present in dragonflies, cockroaches, crickets, grasshoppers and termites. At full metamorphosis, the young insect looks different and must change dramatically to become an adult. Thus, bees, beetles, butterflies, moths and flies undergo complete metamorphosis.



Caterpillars undergo a complete metamorphosis into a completely different adult form

The round or oval convex eyes of butterflies are hemispheres that occupy most of the lateral surface of the head and have a complex facet structure. Let us recall that compound eyes (sometimes called compound eyes) are the main paired organ of vision in insects, crustaceans and some other arthropods.

It is also surprising that butterflies have color vision. For this reason, they perceive moving objects better. In many species, behind the antennae there are additional parietal eyes - an unpaired light-sensitive organ that is found in fish, reptiles and amphibians. It is believed that it helps insects perceive light intensity and is also involved in the regulation of circadian and seasonal rhythms.

How butterflies appear

A butterfly's life begins in a small round or oval egg, the shape of which varies depending on the type of insect. Most butterflies lay numerous eggs on leaves, to which they attach using a sticky liquid. A mother butterfly can lay hundreds of eggs at a time, as many of them will not survive to the final stage of metamorphosis.





In addition to the pattern on their wings, butterflies have a whole range of special adaptations that help them survive.

Once the butterfly hatches from the egg, it becomes a larva and spends most of its time eating, including the leaf on which it was born. In fact, caterpillars can be quite picky when it comes to food - they have to choose which leaf to eat.

This is why it is important for the butterfly to lay its eggs on a leaf, which the caterpillar will then eat. So, monarch caterpillars only eat milkweed.

Once the caterpillar starts eating, it grows. Some internal organs begin to change and reach full growth approximately two weeks after the first meal. Because their exoskeletons do not stretch, they grow by molting or shedding their skin several times, just like snakes.

From caterpillar to chrysalis

Having reached the third stage of development, the caterpillar prepares for the following: as soon as it finishes eating and growing, a shortage of juvenile hormones occurs in its body - insect hormones that regulate their stage-by-stage development. Under their influence, the caterpillar begins to form a silk cocoon or shiny pupa around itself, rushing towards radical changes. The cocoon is often hidden under branches, in a pile of leaves, or underground.

From the outside, it may seem that nothing is happening inside the pupa, but this is not so - inside the cocoon, the caterpillar dissolves in a special substance similar to soup. It is formed with the help of enzymes triggered by hormones.



The shape of the pupa resembles a bullet. Most often, butterfly pupae are brown and shiny.

Then the tissues, limbs and organs begin to change and the caterpillar gradually takes the form of a beautiful butterfly. She develops new colors, wings, long legs and antennae, as well as large eyes and other characteristics of an adult insect.

The mouth turns from chewing into a proboscis, with the help of which the butterfly sips nectar - they cannot eat solid food. These metamorphoses occur over several weeks or months.

From cocoon to butterfly

The final stage of the complex transition from caterpillar to butterfly begins after the insect breaks out of the cocoon. But even at this stage, it takes butterflies some time to extend their legs and antennae and pump hemolymph (a blood-like substance in insects) into their wings in order to fly.



Antennae help butterflies navigate their surroundings by sensing air vibrations and various odors.

This stage, however, does not pass quickly - the butterfly has to wait until the wings dry out and grow to full size. Once the waiting time comes to an end, the butterfly flies away and looks for a new mate so that this complex process can begin again. Some butterflies live only a few weeks, while others can live for months.