The vision of insects
Insects (arthropods) can have three types of visual receptors, or a combination of several.
- Dermal Receivers: without being dedicated to the vision cells, some species have parts of your body that are sensitive.
- Ocelli: also called "simple eyes" as they are composed of a single receiving unit, or "ommatidia". Most insects have these eyespots, either singly or in small groups.
- Compounds Eyes: Flying insects, they need greater visual resolution, have what is called "compound eyes", which consist of multiple eyespots or receiver units (ommatidia) (reaching 30,000 found in some species of dragonflies). Each ommatidium is formed by a lens, forming the surface side of each what is called a "facet", a transparent crystalline cone, sensitive cells distributed radially around the rhabdom, which acts as a waveguide to transmit signal, forming an inverted image photosensitive cells retinulares; pigment cells and separating each other receiver.
Thus we see that the images that form in the brain of the insect compound eyes are made up of a mosaic of tiny individual images are combined to generate an image formed of small "points" .in a way it resembles a digital image in which each pixel is the image captured by a particular ommatidium.
While these compound eyes are superior to ours in some points, we can say that in general, insects are worse than us. In fact, returning to the metaphor of digital images, we see that the insects are better or worse depending on the number of ommatidia present in his eye, and as a rule, this number is not high enough to match the quality of the image that we grasp.
According to studies, we can say that a bee sees about 60 times worse than us, that is, an object that we could discriminate 60 meters, a bee can only discriminate against one meter. Part of the problem is also that the compound eyes are unable to focus.
But not everything would be disadvantages: the compound eyes lend the insect excellent peripheral vision, thanks to the arrangement of ommatidia, which in insects with better vision are usually arranged in a hemisphere.
Insects and color
Most of the insects, the images that form in the brain of the insect compound eyes are made up of a mosaic of tiny individual images are combined to generate an image formed of small "points".
They have two kinds of pigments, allowing them to differentiate some shades of pigment colores.Los receptors of insects are more displaced toward the ultraviolet humans, allowing them to clearly see this radiation. One of these pigments absorb ultraviolet and blue and the other absorbs green and yellow. This means you are not able to discriminate other pure colors that are a combination, much like the color blind but displaced to the ultraviolet frequencies. In addition, they can not see too well the red or pur.
Some insects such as bees, bumblebee, dragonfly or have three types of pigment recipients, which can differentiate colors (360 nm (UV), 440 nm (blue-violet) and 588 nm (yellow-green-red.