Sep 7 2016
When spider silk is plucked like a guitar string, it tends to transmit vibrations across a wide range of frequencies, carrying data relating to mates, prey, and even the structural integrity of a web. This phenomenon was revealed through the work of a research team led by the University of Oxford two years ago.
Recently, a partnership between Oxford and Universidad Carlos III de Madrid has verified the fact that spider webs are superbly tuned instruments for vibration transmission, and that the type of data being transmitted can be manipulated by modifying factors such as web stiffness and tension.
Researchers from the Oxford Silk Group, along with colleagues in Oxford's Department of Engineering Science and Universidad Carlos III de Madrid's Department of Continuum Mechanics and Structural Analysis, have explored the connections between web silk properties and web vibration.
Their findings have been published in the Journal of the Royal Society Interface and it concluded that spider web vibration is influenced by changes in silk stiffness, web tension, and web architecture, all of which can be controlled by the spider.
Web-dwelling spiders have poor eyesight and depend mostly on web vibrations to gain a sense of their surroundings.
The musical patterns transmitted by their tuned webs offer them vital data on the type of prey trapped in the web and of any approaching predators. The quality of potential mates can also be sensed via these patterns.
Similar to constructing and tuning a musical instrument, spiders meticulously spin their webs using a range of silks to control web architecture, stiffness, and tension.
Advanced methods were used by the multinational and interdisciplinary team to investigate how vibrations were transmitted through a web. High-powered lasers were able to measure the miniscule vibrations, which allowed the researchers to produce and test computer models with the help of mathematical finite element analysis.
These methods probe the connection between silk material properties and the propagation of vibrations.
These recent observations suggest that the spider is capable of using silk properties and behavior to manipulate the function of its web structure. These control mechanisms could modify vibration filtering, as well as direction to and discrimination of vibration sources in the web.
Dr Beth Mortimer, lead author of the report, which made use of the garden cross spider Araneus diadematus, said: 'Spider orb webs are multifunctional structures, where both the transmission of vibrations and the capture of prey are important.'
It is down to the interaction of the web materials, a range of bespoke web silks, and the spider with its highly tuned behaviour and armoury of sensors that allows this virtually blind animal to operate in a gossamer world of its own making, without vision and only relying on feeling. Perhaps the web spider can teach us something new about virtual vision.
Professor Fritz Vollrath, Head of the Oxford Silk Group