Unlike the developed arthropod species, arachnids have low vision. Their eyes have a simple structure. There can be up to six pairs on their body, but this more likely confirms the fact of imperfection of their perception of the surrounding world. The answer to the question of how many eyes a scorpion has will not be able to give a clear understanding of the quality of its visual system. Therefore, it makes sense to figure out how he adapted to survive with such imperfect "optics."
Features of arachnids
Various species groups of this class have adapted well. For many, the primary role is played not by the eyes, but by tactile sensations. On the surface of the body they have areas with increased sensitivity. Especially a lot of tactile hairs on the jointed legs, responsible for movement, and on the pedipalps (tentacles).
Many arachnids weave hunting nets. From the smallest fluctuations in the threads, they learn about the prey. Visual perception is less important. Species leading a nomadic lifestyle and hunting without cobwebs have a more developed vision. To move around unfamiliar areas, they must be able to distinguish between surrounding reality.
However, their visual system does not compare with the "optics" of developed higher insects. The eyes of a scorpion (photo below) also do not differ in either the complexity of the device or the features of color reproduction. It is believed that representatives of this suborder see even worse than spiders and are able to distinguish their own kind only from a distance of several centimeters.
Simple and complex vision of arthropods
Vision in insects is most developed. In this regard, the eyes of arachnids are often called simple. In developed representatives of insects - bees, dragonflies, flies and other similar ones - complex eyes have a faceted structure. The structural visual unit is ommatidia. Of them, in fact, is a complex optical system. Located nearby, they make up the visual complex. Ommatidium consists of a biconvex lens (cornea), under which there is a transparent cone, similar in properties to the lens.
Below is a layer of cells (retina), capable of perceiving light radiation. They connect to the nerve endings that transmit signals to the brain. From each ommatidia information comes separately. As a result, the picture consists of many points and resembles a mosaic image.
In flies, the number of such structural elements reaches 4 thousand in each eye. The more developed dragonflies in this regard, and even more - up to 28 thousand. Arachnids are known to have several pairs of eyes. How many eyes does a scorpion have a complex structure? They do not have a complex visual system. It is represented by several separately located ommatidia eyes. And one of them is a larger pair and is considered the main one. The rest (up to 5 pairs) are located on the side and are considered auxiliary.
Simpler lateral eyes (stemms) are found in insect larvae. Moving to the highest stage of development, their visual system becomes more complicated. Another type of simplified eyes (dorsal) is not “reborn”, but remains at the same level in adults. Ommatidium is not formed in them (there is no cone and lens). Underneath the cornea are light-sensing cells. Even lower is the pigment layer connected to the nerve endings.
Scorpions: lifestyle
These arthropods are most often found in regions with a tropical climate. Some species lead a daily lifestyle, but the vast majority of them are still night hunters. They prefer to hide from the scorching heat and hide during this period under stones, snags and in other secluded places.
This is partly due to their imperfect vision. They can notice danger only at close range, and they are better adapted to hunt at night. But this is not only because of the specific features of vision. It doesn't matter how many eyes a scorpion has (photo below) - they do not play a decisive role in catching prey. It is believed that the main merit of accurate attacks is sensitive sensors on their paws.
The circular setting of the legs gives the scorpion the opportunity to feel the smallest vibrations of the soil from all sides. By the speed of propagation of such signals (the near legs feel them earlier), it determines the exact location of the victim. The eyes play a secondary role in this. It is noticed that if the scorpion and the victim are separated by an obstacle in the form of a thin cleft, he will not be able to attack her even from close range. Signals on the soil from the movement of prey to its sensitive legs in this case do not reach.
