Oxford scientists demonstrate how spider webs are superbly tuned instruments for vibration transmission; relaying information on prey, potential mates and web condition. Matthew Stock reports.
Spider silk transmits vibrations across a range of frequencies, much like the strings on a guitar. The tiny tremors propagate through the web to where the spider sits waiting - delivering information on prey, potential mates and web condition. Taking a web from the garden cross spider, scientists from the University of Oxford sent measured pulses into silk strands using laser vibrometry. SOUNDBITE) (English) DR. BETH MORTIMER, ZOOLOGY DEPARTMENT, UNIVERSITY OF OXFORD, SAYING: "Where a laser measures very small scale vibrations on the silk fibres if you focus the lasers on them. We were able to input our own vibration into the web, move this vibration around to different locations to work out how the spider is able to locate where vibration sources are coming from and how the vibrations change as they move through the web structure." They found that a web is a perfectly tuned instrument for getting spider senses tingling. Computer models show how a spider can alter wave vibration amplitude in the web by changing web tension and silk stiffness. (SOUNDBITE) (English) DR. BETH MORTIMER, ZOOLOGY DEPARTMENT, UNIVERSITY OF OXFORD, SAYING: "They're able to very closely change the tension of their webs during web building and outside of web building as well. This means they have a mechanism for directly controlling both the tension and the stiffness of their silk fibres, which we've shown in this paper has a direct effect on how the vibrations move through the web. So it's these mechanisms that are available to the spider that allow them effectively to tune their web's properties so that they can control how sensory information is getting to them in the middle of the web." By shaping the physical properties of its self-made materials and architectures, spider silk may have evolved for this purpose, say researchers. The study was published in Journal of the Royal Society Interface. Similar tests are planned on webs from more exotic species of arachnid, including these golden orb weaver spiders. Scientists hope to understand how they turn physical cues into information within their bodies.