Why Can I Sense Spiders?
WouterThe spider’s mechanosensory system is an example of an intimate relationship between the physical properties of the stimulus and the structures that receive it. It is also an example of the remarkably ingenuity of the spider’s sensory apparatus.
Although it was once thought that spiders could not hear, a study from Harvard University suggests that jumping spiders are very good at recognizing the sound of biological motion. This ability allows the creatures to distinguish between animate and inanimate objects in their peripheral vision.
Researchers tested this by presenting the spiders with point-light displays. Each display consisted of dozens of small lights attached to key joints. The spiders had to move around the displays in order to see their images.
The spiders’ ability to recognize these movements, which are called “biological motion,” may lead to a deeper understanding of the way creatures perceive their environment. It also enables spiders to avoid predators.
The arachnids also use their webs to expand their awareness of the environment. They can sense vibrations from the web as it moves and detect airborne vibrations from sounds in the vicinity. Moreover, some spiders amplify their abilities by feeling changes in their web.
While scientists have known that spiders can hear for many years, this study is the first to show how they do it. It is also the first to show how much attention they pay to the low-frequency sounds that can trigger an anti-predator response.
In addition to detecting movement, they can tell which prey is coming toward them. This ability is facilitated by the presence of four pairs of eyes. However, most spiders are unable to see far away.
