How Spiders Make Sense of the World Around Them

By Kevin Ritchart

In comic books, it takes being bitten by a radioactive spider for a teenage photographer to develop his “Spidey Sense,” but did you know that spiders can gather information about the world around them just by feeling the vibrations and sound waves that travel along their webs?

Researchers from several universities have been studying the way spider webs vibrate and how spiders use those vibrations to gain information about what’s happening around them. These super-sensitive arachnids use web vibrations to know when they’ve caught a meal, when a potential mate is approaching and even when their web might be in need of repair.

Scientists extracted golden silk from an orb weaver spider and tested it alongside other natural and manmade materials to measure how sound waves moved through each of the different kinds of fibers. Researchers also shot bullets at the fibers to gauge the responses to high-speed ballistic stimuli.

Setting the Tone

It turns out that spider silk is highly sensitive, and it can essentially be “tuned in” to various tones that allow spiders to listen to the world around them. Spiders use slit sensillae, which are small grooves on their legs that deform when exposed to even the slightest of vibrations, to decode the meaning of the movements around them. When an insect hits the web and gets caught, the spider employs its slit sensillae to interpret the web vibrations as the insect attempts to free itself. As a result, scientists now believe that the size and shape of spider webs could be based on sonic sensitivity.

Engineers are currently exploring ways to use spider silk in the construction of things like lightweight sensors, bulletproof vests, cables and even artificial muscles.