How Do Spiders See?
Spiders have eyes that are different than those of insects. These are very sensitive to motion and light, and they can detect very small movements of their prey. However, most spiders have very poor vision.
Some spiders can detect vibrations in their web. They can also sense a slight movement of a cricket. Their eyes also allow them to see ultraviolet and green light. This allows them to catch their prey even at night.
Another group of spiders have eyes that can see color. These are called jumping spiders. Jumping spiders are active hunters during the day. To attract a mate, they sometimes use elaborate dances.
Their color vision can extend from blue and purple hues to the deep violet end of the spectrum. Researchers are now studying how jumping spiders’ eyes work together. Understanding how they perceive the world may help in future technologies.
The principal eyes are located at the back of two long tubes. They are controlled by six muscles. When locked on a cricket, these eyes wiggle and twist slightly. At the same time, they scan the silhouette of the cricket.
The secondary eyes are located on the side of the head. They give the spider a more or less 360-degree view. These smaller eyes are used to detect objects that need the attention of the big, high-resolution eyes.
There are three other pairs of eyes. The secondary eyes, on the opposite side of the spider’s head, are thought to be motion detectors.