Not only curious students, but also manyadults are interested in the question: is a spider an insect or not? Indeed, at first glance it may seem that the answer is obvious, and spiders are one of the species of insects, but this is not so. They belong to a separate class of arachnids, because they have a lot of differences with insects.
Spiders appeared on our planet a long time ago,about 400 million years ago. It is believed that they came from a crab-like ancestor. Insects appeared almost 100 million years later and created a separate class. Today on earth live about 40 thousand species of arachnids. If you look in detail at the anatomy of these creatures, then questions like "Is a spider an insect or not?" should not arise. Everyone knows that insects have six legs, but there are eight of them in arachnids, in addition, they have eight eyes, only in some species six or two. These creatures have no teeth, but there are hook-shaped jaws with special channels designed to penetrate the poison into the victim's body.
Doubts about whether a spider is an insect or not,will disappear immediately if you consider how he eats. If the praying mantis eat the caught flies, then the arachnids can not do so because they have extraintestinal digestion. They inject the digestive enzymes, which turn an insect into soup, and spiders only have to suck the contents of the shell.
Many creatures are able to spin the web, but they haveit will not turn out to be as strong and elastic as the trap for the victims, which the spider prepares. Reproduction also causes these creatures to weave special cocoons to preserve the laying of eggs and small spiders. If we compare cobwebs with steel, then the first will be five times stronger than the second, and a thread thick with a pencil will not be able to break through the airplane crashed into the network.
It is unclear why many people are pondering the questionabout whether a spider is an insect or not: between these two classes there is a significant amount of differences. The body of these creatures is divided not into three, but only into two divisions: the abdomen and the cephalothorax. They make the web from liquid, allocated from warts located at the end of the belly. From this material, spiders build houses for themselves, make a carpet-plane on which they move for long distances, weave cocoons for eggs, nets hunt for insects.
These creatures move rather quicklyTheir networks, while mosquitoes, flies and other unfortunates just stick to it. The fact is that spiders weave sticky and non-sticky threads, the first ones are needed to catch the victim, and the second they move. Even if they get accidentally on the sticky part, they will not get confused, since their body has a fat coating.
Современная наука уже дала точный ответ на вопрос:"A spider is an insect or not?", Singling out these creatures in a separate class. In the central strip of Russia, there are no spider-like life-threatening spirits, although it is necessary to behave with them carefully. A spider will never attack first, he only defends or bites at fright. The bite can only be accompanied by burning, severe pain and fever. But there are also dangerous representatives of this species: the most famous are tarantulas and karakurt. Their bite causes a common poisoning of the body, which sometimes leads to death.
