We know that spiders can sense prey in their webs thanks to web vibrations captured by their sensitive feet. Now they seem to be able to listen through this web as well.
Many animals on Earth have eardrums in their ears that pick up vibrations in the air. These vibrations are then transmitted and amplified through the bony structures, eventually moving fluid deeper into the ear. Tiny cilia in the fluid pick up that movement and convert it into electrical signals that go to the brain.
In a recent paper, researchers looked at what spiders do in the lab when vibrations in the air strike their webs. They saw that spiders changed body position and direction in response to sounds. Even if it came from afar. They responded at 68 decibels, while their main enemies – cockroaches, birds and frogs – produced a noise speed of 80 decibels. This indicates that spiders can hear their enemies from a distance of 10 meters.
If the results are confirmed, it means that the spiders also use their webs as an external eardrum. An animal’s first intelligent auditory solution would not be, for example, another species of spider that listens for the hair on its legs. Anyway, it shows that we still don’t know everything about the special materials and functions of a spider’s thread.
Read more: Hearing has been outsourced to an orb-weaving spider that uses its web as an auditory sensor (pre-print).