The sound of a spider web, plucked like a guitar string, provides its inhabitants with information about prey, mates, and even web’s structural condition, scientists have found.
The spiders use that quality by “tuning” the silk, they say: controlling and adjusting its properties, and threads’ tensions and interconnectivities.
The finding comes from researchers from the Universities of Oxford, Strathclyde, and Sheffield in the U.K., who fired bullets and lasers at spider silk to study how it vibrates. They found that unlike many other materials, spider silk is tunable to a wide range of harmonics, or simple pitch relationships.
The findings, to be reported in the journal ”Advanced Materials”, not only reveal more about spiders but could also inspire a wide range of new technologies, such as tiny light-weight sensors, the researchers said.
“Most spiders have poor eyesight and rely almost exclusively on the vibration of the silk in their web for sensory information,” said Beth Mortimer of the Oxford Silk Group at Oxford University, who led the research. “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.”
To study the sonic properties of the spider’s gossamer threads the researchers used ultra-high-speed cameras to film the threads as they responded to the impact of bullets. In addition, lasers were used to make detailed measurements of even the smallest vibration.
“The fact that spiders can receive these nanometer [millionth-of-a-millimeter] vibrations with organs on each of their legs, called slit sensillae, really exemplifies the impact of our research about silk properties found in our study,” said Shira Gordon of the University of Strathclyde, a co-author of the report.
“These findings further demonstrate the outstanding properties of many spider silks that are able to combine exceptional toughness with the ability to transfer delicate information,” said Professor Fritz Vollrath of the Oxford Silk Group at Oxford University, an author of the paper. ‘These are traits that would be very useful in light-weight engineering and might lead to novel, built-in ‘intelligent’ sensors and actuators.”
“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,” said Chris Holland of the University of Sheffield, another co-author.
Added Mortimer: “It may even be that spiders set out to make a web that ‘sounds right’ as its sonic properties are intimately related to factors such as strength and flexibility.”
Source : http://www.world-science.net/