Spiders are well-known for their ability to build intricate webs to trap small prey. Now, new research suggests that insects pluck at the strings of their webs, to identify other spiders, potential meals and more.
When plucked, the strands of spider silk in a web will vibrate, much like a string of a guitar. These vibrations reveal significant information to the spider, including the structural integrity of the trap and whether potential mates may be approaching.
Scientists from the Universities of Oxford, Sheffield, and Strathclyde in England took part in this new study. The team fired laser beams and particles at spider webs, recording the way vibrations traveled along the strings. The lasers were used to detect even the tiniest vibrations in the fibers, and high-speed cameras recorded the movements.
Spider silk can be tuned to a wide range of harmonic frequencies, the investigators found. This could assist the tiny animals, who have notoriously poor eyesight, and may depend on these vibrations to guide their behavior.
"'The sound of silk can tell them what type of meal is entangled in their net and about the intentions and quality of a prospective mate. By plucking the silk like a guitar string and listening to the 'echoes' the spider can also assess the condition of its web," Beth Mortimer, from the Oxford Silk Group at Oxford University, said.
Spiders constantly adjust the properties and connections of the individual strings of their webs, in order to produce different vibrational qualities where needed.
Spiders could even use vibrations while constructing the webs. By plucking at the strings, they could test the fibers, making sure they will help provide a "sensor array" in for the arachnid.
"Spider silks are well known for their impressive mechanical properties, but the vibrational properties have been relatively overlooked and now we find that they are also an awesome communication tool. Yet again spiders continue to impress us in more ways than we can imagine," Chris Holland, one of the investigators who participated in the study, said in a press release.
Benefits of studying the ability of spiders to detect fine vibrations in their web could extend beyond biology.
"These are traits that would be very useful in light-weight engineering and might lead to novel, built-in 'intelligent' sensors and actuators," Fritz Vollrath, of the Oxford Silk Group at Oxford University, and co-author of the article announcing the findings, said.
Investigation of the acoustical properties of spider webs was published in the journal Advanced Materials.