Spider | Facts & Information

Origin

The suborder Opisthothelae contains the infra - order Mygalomorphae, which consists of the forms with "straight jaws", usually large, like the Spider-mole and tarantula, and the infra-order Araneomorphae, whose members have modified and more efficient chelicerae.

It contains the most common and remarkable forms: the blind Weaver, the wolf spider and the jumping spider. Some spiders (cribellate-araneomorphs) have the cribellum gland, which helps produce silk.

Spider is a common name for 34,000 species of eight-legged arthropod animals used for walking, head extensions with pincers and poison glands, and special reproductive organs on the second part of the male's body. They very often use the Silk they secrete.

Like other arachnid species, spiders are terrestrial, although some species have adapted to life in fresh water, catching air bubbles underwater and carrying them after them. Spiders are particularly numerous and are found all over the world. Although most are less than 1cm long, the largest has a 9cm body and legs can be much longer.

Spider Feed

The digestive system of spiders is adapted only for liquid food, because the animals generally digest their prey outside the body, and then ingest the liquid.

The brain is quite complex. Different parts of it are developed, depending on how it locates its prey: by sight or by touch.

Spiders are generally carnivorous and feed only on live food, which they can crush with pliers, or inject venom. The bite of some large spiders can be painful, but most are too small to penetrate human skin, and only a few species are dangerous to humans.

Among them are the "Black Widow" and her close relatives, who, however, are not aggressive and bite people only in defense. The bite is painful and is followed by fainting, shortness of breath. It is only rarely fatal, especially in healthy adults. However, medical care should be provided as soon as possible.

Spider Features

The structure of the body in spiders is similar to that of other arachnids, being divided into an anterior part, called the cephalothorax or prosoma, and a posterior part, called the abdomen or opiosthoma.

The two parts are separated by a thin" neck " that gives the animal the flexibility needed to use its own Silk. Cephalothoracs typically have four pairs of simple eyes, which tend to be larger in spiders that Hunt and smaller in those that create webs with intricate patterns.

Each first pair of pliers, or chelicerae, has a corner provided with an opening through which poison from a gland at the end of the pliers is released. The next two parts of the body are called pedipalps, they resemble legs, but are generally modified to become a kind of antennae.

In the male, the pedipalp has a" palpation organ", used in reproduction. On the cephalothorax there are also four pairs of legs used for walking. On the abdomen are modified tongs, used to secrete silk.

Openings on the abdomen lead to the book lungs, so named because of their layered structure, or a system of tubes(trachea) used to carry air. In some species, both types of breathing can be found.

Spider silk is a fibrillous protein that is secreted like a liquid and that forms a polymer that by stretching is more resistant than steel and very elastic. A single spider can create several kinds of silk.

Although other invertebrates secrete silk, spiders use this ability in most ways. For example, they form wires that help them find their way and do not let them fall.. Small spiders, but especially young ones, form parachutes that help them to be carried by the wind, sometimes for hundreds of kilometers.

The male uses silk to transfer sperm to the female, and she makes silk Donuts. Silk is used to build the nests and align them. The most familiar, and yet the most amazing use is in the construction of traps for insects, called "canvases". Once the prey is caught, the Spider wraps it in silk again. The various cobwebs provide a remarkable example of the evolution of instical behavior.

Painters do not have to learn to make canvases, but can adapt the technique to special conditions, such as the lack of weight in spaceships. The simplest are irregular and lying on the surface of the Earth. The most advanced ones are particularly elaborate and oriented in such a way as to intercept the trajectory of flying insects.

The formation of the canvas is a complex process that involves a combination of sticky pieces with non-sticky ones. Sometimes several spiders form a kind of common web, but spiders are generally not sociable. Such spiders rely mostly on groping.

As predators of insects or small animals, spiders are generally useful to humans, although some feed on pollinating insects like bees. They are a source of prey for other animals like some wasps that paralyze spiders and lay their eggs on their bodies.

The use of silk for clothing has not been economically successful, but it is used for high-precision optical instruments. Although spiders have occupied important places in various mythologies, today they are considered repulsive, due to their grotesque appearance and the fact that they hide in dark places, but also due to their exaggeration of toxicity.

Spider Reproduction

Spiders have two sexes, and the eggs must be fertilized. The genital openings of the male and female are on the abdomen, but the male's copulatory organs are complex structures located on the pincers. It secretes silk in which it stores sperm, then moves it to the palpal organs.

After the sperm has been transferred to the female, it can be kept in her body for a longer period of time. The mating ritual is often computed. Males use silk to recognize their mate, or signal their closeness by snatching pieces of the female's web.

In spiders with developed eyesight, the mating ritual is associated with bright colors. The male must avoid being confused with the female's food. Males are sometimes much smaller than females. This is noticeable when the female stops in one place.

Males mature faster, and the sooner they reach a female, the greater the chances of reproducing. Spider eggs are protected in silk cocoons.The female can guard them or take them with her. In some species, the Cubs stay with the mother for a longer period and are carried on her body.