Why Do Jumping Spiders Raise Their Arms?
WouterJumping spiders use their vision to locate prey, detect potential attackers, and study their environment. Their visual system is similar to the human visual system and includes eight eyeballs. The AL (anteromedian) and PL (posterior lateral) eyes are used to track and locate moving objects.
The ocular structure of jumping spiders is complex and unique. Aside from the four primary eyes on the front of their head, they have two smaller eyes on each side. The centre of the retinas has ten times more receptors than the periphery.
The visual system of jumping spiders is similar to that of other arthropods. They have six muscles that encircle the eye-tube. Each muscle is controlled by an axon that terminates in one of the six muscles. This allows the muscle to move the retinae. The AL eye has a larger field of vision than the PL.
When it comes to the speed of their movements, jumping spiders are slow. Unlike humans, spiders do not have any special muscles that are designed to propel them. However, they do have a mechanism that increases blood flow to their legs. This increases the length of the legs and allows them to be able to extend them when necessary.
When they feel they’re under attack, they will raise their front legs. This act is an important defensive mechanism, as it deters predators from attacking them. It also gives them a larger appearance and allows them to intimidate small spiders.
