A compound eye may consist of thousands of individual photoreception units. The image perceived is a combination of inputs from the numerous ommatidia (individual "eye units"), which are located on a convex surface, thus pointing in slightly different directions. Compared with simple eyes, compound eyes possess a very large view angle, and can detect fast movement and, in some cases, the polarization of light. Because the individual lenses are so small, the effects of diffraction impose a limit on the possible resolution that can be obtained. This can only be countered by increasing lens size and number — to see with a resolution comparable to our simple eyes, humans would require compound eyes which would each reach the size of their head. (source wiki)
Because insects can't move their compound eyes they use Antennes to aim their view.
In insects, olfactory receptors on the antennae bind to odour molecules, including pheromones. The neurons that possess these receptors signal this binding by sending action potentials down their axons to the antennal lobe in the brain. From there, neurons in the antennal lobes connect to mushroom bodies that identify the odour. The sum of the electrical potentials of the antenna to a given odor can be measured using an electroantenogram.
Also othe animals have antennas, such as crabs:
Comments:
Q1: Just to throw some confusion into the mix, I breed a lot of insects, from mantids to beetles. Some for fun, some for study, and most to feed to my reptiles/amphibians/arachnids/mammals.
I have a LOT of Gryllus bimaculatus (African Two-Spotted Cricket), and I observe them very carefully for any new characteristics that may arise by mutation etc. Recently, I found one with fused antenna. I took care of it, making sure it didn't get eaten by an others, but I didn't give it a life much easier than that. It had to search for food and navigate objects in a complex environment. This little fella lived all the way to his adult phase (growing his wings after the fifth shed) and died a pretty natural death of old age at approx 8 weeks old. It didn't seem to suffer from its condition in any way at all and successfully navigated the environment in order to find food/water.
A1: I have taken a look at these 'crickets' and they don't seem to be using their antennae as visual alignment elements. Their antennae may have started of as an alignment element but evolved into something else
Q2:Why? How did you decide this?
A2: Because these 'crickets' seems to live in groups close to each other, and if it should rely for sight on these long unsteady antennae he/she could easily get very dizzy as they don't seem to be stable. And the antennae are often directing to the back like someone with long hear to not block his/her sight. It also doesn't seem to fly (small wings) so to need such long aiming tools, he/she would be aiming at something in a distance and it would take him/her a very long time hopping around to get there. It also lives perhaps close to the ground between leafs and such where there is not light so. That's why it has tiny eyes like lobsters who live on the bottom of the sea and have similar antennae.
Q1: Do you have any evidence that insect antennae provide direction markers for their fields of view, or is it just a guess?
A1: I wouldn't call it a guess, it lay's more in line of the rest of my theory …
Some observations about the dragon fly; it has a long tail to stay in balance in contrast to butterflies, it has also 2 pair of wings to stay in balance like a helicopter has two rotors. It's head can move relatively freely so it can keep it's head steadily focused on pray as it does have to small antennae, look at the examples on the wiki page: http://en.wikipedia.org/wiki/Dragonfly. Now the Dragon Fly doesn't go after flowers or any other steady feeding object. It are valuable predators that eat mosquitoes, and other small insects like flies, bees,… So long antennae aren't of any use while flying up close to them and catching them, having long antennae would let the pray always get away.
Note, it always has the same type of markers on the front ends of it's wings.
And it also seems to have different gradations in it's eyes, where of some in possible reference to the markings on their wings.
Q2: Your theory? Would you really say you're that far along with it?
A2: It
is not so much my theory it is a physiological principle, that I
experienced by changing the masking of my eyes. This gave me the
opportunity to understand some of the basic mechanics of our sight, and
how it's applicable for nearly every organism. Masking helps us to
align and stay in balance, to move and see in a particular way, to
observe, track pray…
It's like the moon when it is closely to
the ground it looks bigger, because the relation between a steady
object (earth/us) and the a free object is shorter and thus more
stable. Also the framing is different when the elements are closer in
'play'. The earth and the buildings are masking elements who give us
alignment to rest our sight upon.
In
our early development stages we had to move our whole body to look
around to catch pray like crocodiles, fish…. The more we could detach
the action of looking around from moving our body the more freely our
brain has developed, but the basic principles of alignment are still
there.
We look around, not only by eye-rotation but by refined
body movement, bending of knees, hips, upper-body, shoulders, neck,
this gives us almost unlimited freedom to look around and align
ourselves to our environment. And over time it has given us the
impression that we only look by moving our eyes.
The
purpose of this site is to present questions and new ideas about
the above subjects.
A compound eye may consist of thousands of individual photoreception units. The image perceived is a combination of inputs from the numerous ommatidia (individual "eye units"), which are located on a convex surface, thus pointing in slightly different directions. Compared with simple eyes, compound eyes possess a very large view angle, and can detect fast movement and, in some cases, the polarization of light. Because the individual lenses are so small, the effects of diffraction impose a limit on the possible resolution that can be obtained. This can only be countered by increasing lens size and number — to see with a resolution comparable to our simple eyes, humans would require compound eyes which would each reach the size of their head. (
The
purpose of this site is to present questions and new ideas about
the above subjects.
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