Post #13704

Is it true that the insect inside the pupa completely dissolves and is reassembled? What does an insect look like at the moment between childhood and maturity, in the pupa? The answer will not please particularly impressionable readers: if you open the wrinkled cocoon in the midst of transformation, a strange mass similar to jelly will appear from it! The body won't be there! Does the insect really dissolve completely in the pupa? And how, then, is it reassembled? To understand what is happening, you need to know what the pupa is filled with. Part of the strange substance is metalloproteinases. Special enzymes that break down proteins into their components. How did they get there? So the old body of the caterpillar must be destroyed somehow! It won’t be able to fall apart on its own; surrendering to the destruction of bacteria and decomposer fungi is also not an option; they will, so to speak, spoil the product. In fact, insects have to digest themselves. How soup-like the body inside the pupa will be depends on the order of the insect. In addition to butterflies, all insects with complete transformation have a transitional form: beetles, mosquitoes, flies. For most of them, the body turns into something resembling frozen jelly for a couple of days. Cells keep each other on their word of honor. In this state it is convenient to sculpt something new from them. Let's take a caterpillar as an example. The cells that used to be its legs will remain in place and will simply reassemble into the limbs of an adult insect. The cells that were once protective bristles will disintegrate. Butterflies don't need them. But the nutrients from the extra body part are very useful for the growing body. And some organs will generally remain unchanged: the anterior and posterior parts of the intestine, the trachea, the excretory system. But what to do with new body parts that the larva did not have before? This is where imaginal discs come to the rescue. These are special cells. They are present in insects from birth, but are activated when the larva turns into a pupa and the old incarnation has melted. It is they who, saturated with nutrients, form new organs from everything that floats around them. In many beetles and butterflies, the imaginal discs contain the development of wings and the reproductive system. And in fruit flies, the discs, like a nesting doll, contain the entire adult body! The process of metamorphosis of fruit flies is the most destructive - their body actually almost completely turns into broth. According to the drawings of the imaginal discs, the new, adult organism is reassembled from the old bricks of the larva. It turns out that of all living creatures, fruit flies are the real lucky ones! In fact, they can celebrate two birthdays a year! Photo: 1. Butterfly pupa 2. The caterpillar creates a chrysalis 3. Stag beetle pupa 4. Mosquito pupae 5. Diagram of the imaginal discs of a Drosophila larva (these are the only