Insects live on all continents of the Earth, except Antarctica, and just in huge numbers. Some are striking in size, barely fit in the palm of your hand. Others are so small that it is simply impossible to make out without special equipment. In order to navigate in all this diversity, scientists introduced the taxonomy of insects. We will tell you briefly about her.
The most numerous on the planet
It is insects on our planet that are the most extensive class belonging to the animal kingdom. To date, more than a million species have been discovered. And this is not the end: scientists annually describe another 7-7.5 thousand species. Therefore, according to some experts, their total number ranges from 2 to 8 million.
The number is really impressive! Especially when you consider that the other classes of the "fraternal" arthropod order are not so numerous. For example, millipedes are only 12 thousand species, crustaceans - no more than 73 thousand, and arachnids - approximately 114 000.
Getting confused in such a variety is not difficult. Therefore, the taxonomy of the class of insects was carried out. Thanks to her, each species was given a double name in Latin, which completely eliminates any confusion in scientific circles.
Generally accepted taxonomy
The first taxonomy of insects was carried out in the mid-eighteenth century. Karl Linnaeus himself worked on it, the founder of the modern systematics of all living things on planet Earth. Since then, it has been redone repeatedly. And today different taxonomy is used in different countries. For example, at some points in history, theories were gaining popularity, according to which insects were alternately combined with symphiles and centipedes. Today, some experts believe that it would be right to combine insects with crustaceans - DNA examination proves their close relationship.
Most likely, many more discoveries will be made in the future that will somehow affect the existing classification. But still, the most popular system in our time is that all insects are divided into six main groups that have certain unique properties. Let's talk about each of them.
Winged
Perhaps the taxonomy of the order of insects should begin with this group, as the most numerous. After all, it includes almost 400 thousand different species.
Coleopterans are called all beetles. Their sizes can seriously differ: the largest have a length of up to 17 centimeters, while their miniature brethren cannot boast more than 1 millimeter in length. But all of them are united by the special structure of the wings and the mechanism of their protection.
The wings themselves, when the insect does not fly, fold neatly on the back. From above, they are protected by hard elytra, capable of withstanding significant mechanical stress without harm to themselves.
They develop according to the most complex scheme, which includes as many as four stages: an egg, a larva, a pupa and an imago - that is, an adult insect.
Hard chitinous integuments allow for a long time to be in the sun without harm, preventing dehydration of the body even in the smallest representatives of beetles.
Half-winged
Despite the fact that this group is much inferior in size to the previous one (to date, slightly more than 100 thousand species have been discovered), the taxonomy and classification of insects is difficult because of its amazing prevalence.
Representatives of the semi-winged live in nature and next to humans, in the ground, in the air and even under water. Therefore, not all of these insects have wings. There are species either devoid of wings at all, or those in which they are present only in males. Elytra less rigid than that of beetles, which gave the name to the whole group.
Go through the same three stages of development. The egg turns into a nymph, and that already into an adult insect.
Two winged
It is the representatives of dipterans that cause people the most problems in the warm season. After all, this includes mosquitoes, flies, gadflies and horseflies. The total number of insects in this group exceeds 160 thousand. The sizes vary greatly - from 0.5 millimeters to 6 centimeters and even larger.
The body is rigidly divided into three segments: head, chest and abdomen. They have two wings that do not fold when landing, are not protected by elytra.
Three stages of development pass: an egg, a larva and an adult. Moreover, during the development they can change the habitat. For example, a mosquito larva - bloodworm - lives in water. And the larvae of flies perfectly develop in dead animals, manure or land.
Orthoptera
If we talk about the systematics of insects, the group of orthoptera is the least numerous - it includes only 24.5 thousand species. The most familiar representatives of this family for our compatriots are locusts, grasshoppers and crickets. Their body is elongated, but there are some types of almost round shape. There are both herbivores, and omnivorous or even purely predatory representatives. The structure of the jaws depends on this: in the former, they are directed downward, and in the latter, strictly forward.
Strongly distinguishing from other insects feature powerful hind legs. Long, with large hips, they allow you to make huge jumps, literally shooting the body into the air. This is an interesting feature that made scientists isolate them in the taxonomy of insects into a separate group. After takeoff, some species can fly hundreds or even thousands of kilometers. Surely many readers have heard about the massive flights of locusts, for example, from Africa to America.
Hymenoptera
All the most developed species of insects belong to this group. In total, it includes about 155 thousand representatives. These include bees, wasps, bumblebees and ants. They vary greatly in size. The smallest have a body length of not more than 0.2 millimeters, while there are real "titans" up to 14 centimeters long.
Body structure can vary greatly. In some representatives, all three segments are clearly distinguished: the abdomen, chest and head. But in some (mainly sedentary), the border between the chest and abdomen is almost indistinguishable.
The legs are predominantly walking, although you can also find insects having limbs adapted to dig and capture the victim.
Many have two pairs of wings: the front is the top, and the shorter rear folds at rest, being under the front. Moreover, in flight, paired wings are connected to one surface, which dramatically increases the speed and maneuverability of insects.
Lepidoptera
But the most beautiful representatives of insects, no doubt, are included in this group. It is quite numerous - almost 160 thousand varieties. The most famous and familiar representatives are butterflies of all types and sizes, ranging from the most beautiful swallowtail and hives, ending with tiny moths. Yes, the size of these insects varies greatly - from 2 to 275 millimeters.
The wings have a special structure, not similar to the device of other insects. The finest material is coated on top with chitinous scales, which are easily damaged, which often causes the death of insects. When landing, the wings do not fold, as, for example, in beetles or wasps, but simply fold, and even then not always.
Conclusion
Now you better understand the taxonomy of morphology and biology of insects. Of course, the topic is too extensive to be covered in one short article. But you learned the main features and now you can easily classify most of the insects encountered.