Lethal spider’s web sheds light on material strength

A transatlantic team of researchers has discovered the secret behind the immense strength of the brown recluse spider’s silk.

(Credit: Oxford University)

Known as one of the world’s most venomous arachnids, the brown recluse’s silk is also the strongest found anywhere in the spider kingdom. Now, scientists from Oxford University’s Department of Zoology and the Applied Science Department at Virginia’s College of William & Mary have revealed the source of the material’s exceptional toughness.

Published in the journal Material Horizons, the research describes how the spider uses a micro-looping technique to reinforce its thread. This is facilitated by the recluse producing thin, flat silk that resembles a ribbon, rather than the round silk produced by other spiders. According to the team, the flatness provides flexibility, which prevents breakage when the strengthening knots are spun.

“The theory of knots adding strength is well proven,” said Professor Hannes Schniepp from William & Mary. “But adding loops to synthetic filaments always seems to lead to premature fibre failure. Observation of the recluse spider provided the breakthrough solution…The ribbon shape adds the flexibility needed to prevent premature failure, so that all the microloops can provide additional strength to the strand.”

(Credit: Oxford University)

The team used computer simulations to demonstrate that fibres with loops were significantly stronger than those without. According to Professor Fritz Vollrath from Oxford’s Department of Zoology, the technique could be used with synthetic materials for a range of applications.

“For example, carbon filaments could be looped to make them less brittle, and thus allow their use in novel impact absorbing structures,” he said. “One example would be spider-like webs of carbon-filaments floating in outer space, to capture the drifting space debris that endangers astronaut lives’ and satellite integrity.”