The metamorphosis of a butterfly is one of the most extraordinary transformations that an animal can perform during its lifecycle. It is simply amazing what they go through to become the beautiful, majestic creatures which we so often marvel at. All butterflies, as well as their close cousins the moths, start off their life as an egg, laid under the leaf of a particular plant. The type of plant is really important, because when the egg hatches, not all leaves will be suitable for the larva to eat. In the beginning the larvae are really tiny and cannot travel very far, so it is crucial that they hatch on a kind of leaf that is appropriate. We call these larvae caterpillars and their only objective is to eat as much as possible. During this cycle they will grow longer and longer, molding their skin several times.
As soon as the larva has grown large enough, it will hang itself from a leaf or a twig and spin itself into a chrysalis. Inside, protected by its new hard casing, something remarkable happens – the whole of the caterpillar digests itself from the inside-out. Everything turns to liquid, apart from several organized groups of cells. These are called imaginal discs and are the basis of the butterfly’s various body parts. These special structures have been a part of the caterpillar from the very beginning, even before it hatched out the egg. In some species they have been dormant up until this moment, while others start developing them during the earlier stages. Around them the protein rich caterpillar soup starts to form into cells and finally a butterfly emerges. When it is ready it breaks out of the chrysalis, pumps blood to stretch its newly formed wings and flies away.
As incredible as this transformation is, what is even more astonishing is that somewhere inside that cocktail of organs and fluids within the chrysalis, the insect retains its conscience and its memories. Scientist have performed a test, where they trained caterpillars to have a negative reaction to the smell of ethyl acetate (the active ingredient of nail polish remover). They did this by giving them a small electric shock every time they were introduced to the chemical, until the caterpillars started to actively avoid it. Then they allowed them to transform into moths and tested their reaction. Almost all of them remembered, proving that the memories survived.
The biggest butterfly in the world is the Ornithoptera alexandrae, also known as The Queen Alexandra Birdwing. It is one of the rarest butterflies in the world, found only in the rainforests of New Guinea. The females have a chocolate brown body and wings and can grow to a wingspan of 31 centimeters. As with many insect species, the males are significantly smaller and grow only up to 19 cm. However, they are much more colorful: their body is very bright yellow, while the wings are in electric green and aquamarine.