Butterflies belong to the largest group of animals, that is, to the one that has a greater number of species: insects. Within this group, his (the lepidoptera) occupies the fourth place in terms of number and diversity of species, after the beetles, hymenoptera and diptera. In CurioSfera.com we want to explain the characteristics of the butterflies, their habitat, where they live, what they eat and much more information about them. 
Characteristics of the butterfly
What are butterflies? You must know that they are insects, and as such, they are also arthropods, butterflies have the basic characteristics of this group. They have the body divided into three clearly differentiated parts: head, thorax and abdomen.
In the head are the mouth, antennae, palps and eyes. The thorax, divided into three segments, has three pairs of articulated legs (one pair attached to each thoracic segment) and two pairs of wings (in the second and third segments). The abdomen is the most segmented part of the body; It consists of ten segments, although only eight are clearly visible. 
A characteristic feature of butterflies are the scales, which cover the entire body of adults, especially the wings; the name Lepidoptera means "wings with scales". In addition to the scales, they present numerous hairs in different parts of the body and, sometimes, also in the wings.
The colored scales, superimposed on one another like the roof tiles, form the wonderful and elaborate drawings of the wings; colors are produced chemically by pigments and physically by diffraction and refraction of light. 
It is very difficult to see the skeleton itself under the scales and hairs that cover it, and it is necessary to remove them in order to see the individual parts of the skeleton. A butterfly that has been "stripped" looks like a toy doll with moving joints.
Like all insects, butterflies breathe through a trachea or series of tubes that carry oxygen to body tissues.
Development and phases of growth of the butterfly
For most people, the word butterfly evokes the image of the adult or imago. In general, we do not think about the complex development that precedes the appearance of the creature with its beautiful shape and colorful wings.
Butterflies, like the rest of insects, undergo a process known as metamorphosis, in which they follow in succession several completely different growth phases, starting with the egg and ending with the adult.
The lepidoptera undergo a complete metamorphosis, passing through four main phases, alternating always an active phase with an inactive or immobile phase. The four phases are:
Egg
Larva or caterpillar
Pupa or chrysalis
Adult 
Below we will explain each of them in detail:
Egg
The life cycle of the butterfly begins with the egg. Eggs can be seen with the naked eye; even those of the smallest lepidoptera are relatively large: from 0.2 to 0.3 millimeters. The larger eggs of the more vigorous lepidoptera can reach the size of a pea: from 3 to 4 millimeters.
The egg is completely covered with a solid shell or chorion that encloses the embryo and the rich layer of yolk that surrounds it and that provides the food for its development. The outer surface may be more or less smooth or rough, coarsely carved with ridges and hollows or decorated with irregular spots. 
The egg shape of the butterflies demonstrates a great diversity and can be spherical, conical, cylindrical, with the shape of a bar, boat or spindle, angular or flat and flake type. The corium has a tiny hole called micropile through which penetrates the mobile sperm to reach the female gamete and fertilize it. The micropile can be located in the upper area of the egg, and the egg is called a vertical egg, or it can be located laterally, in which case it is called a lying egg.
The females can lay their eggs isolated or grouped in characteristic forms: lined up in a row, stacked, in a single layer or in several layers. Sometimes the female makes its placement on the surface of leaves and branches, other times inserts the eggs carefully in fissures of trunks, under young buds or buds, under leaf litter, in rosettes of leaves or flowers.
Regarding the number of eggs that a butterfly puts, you should know that it depends on the species, since it can vary between several hundreds to something more than two thousand eggs in a single laying. 
Freshly laid eggs have soft shell and their color is usually white or yellowish white, although it may be greenish. However, the chorion hardens quickly and the eggs acquire their true color, mostly yellow or pale green, also gray-brown and even black. The eggs of the moths of the Catocala genus and those of the species whose egg-shaped buds have a very vivid coloration.
Sometimes, the coloration can change with the development of the embryo. Pale eggs can acquire reddish marks; other times they take darker colors such as brown and violet. In eggs with thin and translucent shell it is possible to see the head of the caterpillar through the chorion towards the end of the embryonic development.
Caterpillar
After a certain period of time, varying greatly according to species and external factors, small caterpillars leave the eggs. The external factor that most influences egg development is temperature. Also the humidity, by excess or by defect, influences the eggs of some species.
The ideal temperature ranges around 20 ° C or 68 ° F. At lower temperatures the development of the embryo slows down or even stops; at high temperatures (up to a certain limit), development is usually faster.
In two or three weeks, or even earlier, it can acquire a length twenty times greater, a weight and a volume of two thousand to three thousand times higher and the head can increase six times in width.
Not even the most elastic of the skins could withstand such changes in size and, therefore, the caterpillar experiences numerous changes during its development. It is released from the old and tight skin, as well as from the capsule of the head, and replenishes it with a new skin, larger and more comfortable, which had previously developed under the previous one. 
After a few hours, the new skin hardens and the caterpillar can continue to feed again. The period of growth between seedlings is called Instar. There are usually five or six periods of growth, but sometimes there may be more.
However, not all butterfly caterpillars grow so quickly. In some species, the development lasts several months, sometimes even years, and there may be a great difference in the duration of development even among caterpillars of the same species, depending on the seasonal generation to which they belong.
This fast growth needs its corresponding amount of food and, as soon as it leaves the egg, the caterpillar begins to look for it. Frequently, the empty chorion serves the caterpillar as the first food, so that the traces of its birth disappear immediately. For some caterpillars it is fundamental that the chorion is their first food, and if for some reason they can not take it, they do not eat anything else and, therefore, they die.
As for what the caterpillars eat, the moment the caterpillar leaves the egg, the search for the specific foods that make up its diet should begin, be it green leaves, buds, roots, bulbs, wood or anything else. 
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