The Jumping Spider has eyes in three rows in a 4 – 2 – 2 arrangement (or rarely a 2 - 2 – 2 – 2) for a total of 8 eyes. The eight eyes are grouped four on each side of the face. The two big Anterior Median eyes in the middle, two smaller Anterior Lateral eyes to the side, and four on top of the carapace (two medium - sized eyes toward the back, and two very small eyes in front of them).
The anterior median eyes (AME) are very large and tubular in this particular species, anterior
lateral eyes (ALE) slightly smaller. The main eyes are very functional and detect colour and resolution, but only see what is right in front of them. The front pair of secondary
eyes serve as motion detectors, and tell the main eyes where to look.
Furthermore, they also transmit the location of the moving object, after which the brain informs the main eyes to have a closer look.
One can conclude that there is a cooperation between physically separate sets of eyes that is quite remarkable in this species.
Another amazing fact about this species is that they can see in high definition, and can even see in higher resolution than humans or other animal species.
They can see in three colour channels, which means that they possess true colour vision or
trichromatic vision.
The retina is the darkest part of the eye and moves around. When looking directly into it you can even see it changing colour. If it remains dark, it means the spider is looking directly at you.
The lenses are built into the carapace, this means that the retina moves around while the lens stays fixed. It’s no wonder the brain of the jumping spider contains a large region for visual processing due to the fact that so many visual cues have to be processed.
It goes without saying that jumping spiders don’t use their web to catch prey, they do use their silk to make shelter. In order to catch their prey they first stalk their prey, wait for the right moment and then pounce on them. They are able to overpower prey that is 3 to 4 times their size.
The International School Of Veterinary Nursing has courses in Arachnology. For more information, go to www.tisovn.com