flying, spiders, grasshoppers, dragonflies – all of these animals have primarily one thing in common: in comparison to us humans, they are small, even minuscule. Accordingly, we concern ourselves very little with them, even though they are on our planet considerably in the majority. Taking the time to offer amazing insight from the world of the Tiny. And if you get near a dragonfly, or a jumping spider once, up to a few centimeters, and exactly in the eye – the modern photography makes it possible to do so – you will see suddenly a being that radiates just as much character, like a human compared To.

to 28,000 small eyes

Especially in the case of flying insects such as dragonflies, the eyes are clearly the most dominant parts of the body – they make up 90 percent of the head surface and, therefore, appear absolutely huge compared to the Rest of the body. The reason for this lies in the structure of insect eyes: they are made up of tiny individual eyes, the so-called Nuclear, which are close to each other and a great eye make up. Biologists also speak of the facets of the eye. This eye type are found in very different forms and sizes. Dragonflies and flies, for example, have not only the largest compound eyes, but with up to 28,000 Nuclear in one eye, is also the largest density of individual eyes. For comparison: A Firefly has just 300 Nuclear per compound eye.

Compared with the lens eyes of the people, compound eyes offer both advantages and disadvantages. Your advantage lies in the higher temporal resolution: While a human lens of the eye can be a maximum of perceive 60 frames per second, create certain flying insects, with their eyes up to 300 pictures per second – in contrast to the precise flight manoeuvres of these little creatures would not be possible. Another advantage of large compound eyes, the extended field – of-view, this is some of the dragonflies and flying almost 360° - a panoramic view so. People have a field of view of almost 180° degrees. Your weakness to the facets of the eyes have in the spatial resolution and the sensitivity to light; a shortcoming that due to the increased temporal resolution, but is partially compensated.

main-, medium -, and side-eyes

In contrast to many insects called spiders, no compound eyes, but so-called point eyes and Ocelli. Depending on the type of spider these eyes vary in number and Position to the head of the spider. Some species of spiders have eight eyes, which are distributed over the head, others only six. Achtäugige spiders usually have so-called main eyes, which are localized in the center of the front half of the Head. Six-eyed spider, these primary eyes absent. Depending on the spider species, the number of photoreceptor cells varies in the Ocelli – jumping spiders, for example, have a relatively large number of photoreceptor cells in their eyes, funnel spiders, only have very few.

most of The spiders, the possibility is missing to the form to see if your eyes are, in principle, further development of compound eyes and the human eye is more similar than this. Since spiders but no moving eyeballs, you can just look because of around your head is positioned the eyes in more than one direction – the field of view of 360 degrees, but at the same time, so, comparable with that of flying insects. Often six or eight eyes of spiders are very different greatly, so that some of the Ocelli act as a kind of light sensor.

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Date Of Update: 04 June 2020, 02:28