Web (in)sight – a poisonous spider’s silk gives up its secrets

Study analyses the reason why an American spider’s silk is so strong, with implications relating to materials development.

Spider silk
Larry RoweA Brown Recluse spider.

Scientists have launched an investigation into one of the most venomous arachnids on earth in an attempt to discover why its silk is so strong.

The silk belonging to the American brown recluse spider is thin and flat rather than the round form of thread produced by other spiders. This structural difference gives the flexibility required to prevent premature breakage and withstand the knots created during spinning, which give each strand additional strength.

Professor Hannes Schniepp from William & Mary, said: “The theory of knots adding strength is well proven. But adding loops to synthetic filaments always seems to lead to premature fibre failure.

“Observation of the recluse spider provided the breakthrough solution; unlike all spiders its silk is not round, but a thin, nano-scale flat ribbon. The ribbon shape adds the flexibility needed to prevent premature failure, so that all the microloops can provide additional strength to the strand.”

Using computer simulation, the team observed that adding even a single loop significantly enhanced the toughness of a simple synthetic sticky tape.

Professor Fritz Vollrath, from the Department of Zoology at Oxford University, said: “This right away suggests possible applications.

“For example carbon filaments could be looped to make them less brittle, and thus allow their use in novel impact absorbing structures. 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.”

The team, from Oxford University’s Department of Zoology, together with a team from the Applied Science Department at Virginia’s College of William & Mary, published details of the study in the journal Material Horizons.