Researchers use light, sound to untangle spider web riddles
Scientists have found a new way to study spider webs that literally shines a light on arachnid technology like never before.
Using light-scattering technology previously used for studying proteins, collagens and muscle fibers, researchers at Arizona State University measured the strength, elasticity and stiffness of spider webs. Scientists hope what they learn can help them develop new technologies for everyday life.
Researchers collected silk from a garden spider, western black widow, orb-weaver spider and green lynx spider. They also allowed the spiders to spin their own webs overnight, then used a washer coated with super glue to collect the web but preserve its structure.
Previous studies of spider webs have used methods such as studying cross-sections of the spider silk under microscopes. This newest study reveals how light reacts to sound waves passing through the spider silk, similar to how a sonogram works. The method allows scientists to get a detailed image of the entire web, not just pieces of it, said study author Jeffrey Yarger, a professor of biochemistry and physics at ASU.
The ASU researchers found that spider webs contain tiny crystals between the fibers that determine its rigidity. Spider webs also stiffen when wet and are more elastic at “glue spots” where the spider has added adhesive to keep the web taught. In general, spider webs are equally elastic and stiff across species. Even the green lynx, which doesn’t use its web for catching prey, had a similar silk to its predatory relatives, the study found.
Spider silk is “five times stronger than steel and twice as tough as Kevlar,” Yarger said. “If you think of it as per unit weight, because spider webs are incredibly light, it’s one of the toughest fibers to break. We don’t have anything synthetically to compete with it.”
According to researchers, the eight-legged creatures can dictate how much moisture goes into their silk webs, thereby controlling the web’s stiffness.
“This type of behaviour, specifically adjusting mechanical properties by simply adjusting water content, is inspirational from a bioinspired … perspective,” the researchers wrote in their study, published Sunday in Nature Materials.
Scientists said the comprehensive look at webs should provide a blueprint for more engineering projects inspired by biology, including ways to build stronger, stretchier synthetic fibers.
“We haven’t been able to do that because, at a fundamental level, we don’t understand what makes spider silk so strong,” Yarger said.
The study was supported by the Department of Defense and the U.S. National Science Foundation. You can read a summary of it online here.
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