'Static Spider Silk' is Incredibly Thin and Strong

You've likely heard that silk is incredibly strong. Spider silk in particular can be both strong and mind-boggingly thin, hinting that nature is still the master spinster. Now, after studying the remarkable webs of a common garden spider, researchers think they are just a bit closer to learning nature's craft.

When you think of spider webs, a network of thin and sticky webs likely come to mind. It's remarkable how these threads, only several micrometers thick, can span relatively great distances without breaking.

However, what's more amazing still is that some spiders spin silk that is even thinner. According to a study recently published in the journal Biology Letters, the feather-legged lace weaver (Uloborus plumipes) can spin filaments so thin that they are measured on the nano-scale.

So how the heck can a thread be so thin and not even break under a light breeze? Researchers from Oxford University collected several adult female Uloborus lace weavers from garden centers in Hampshire, UK, to find out.

The team closely analyzed video and photographs of the spiders in action, weaving unusual "dry capture webs." These webs rely on their incredibly fine and puffed filaments to tangle and capture prey, as opposed to the sticky fluid that coats the thicker webs of other spiders.

They also closely examined the silk-generating organs of these spiders under a microscope, paying special attention to the cribellum, an ancient spinning organ not found in many spiders that helps facilitate this "dry" silk production.

"Uloborus has unique cribellar glands, amongst the smallest silk glands of any spider, and it's these that yield the ultra-fine 'catching wool' of its prey capture thread," first study author Katrin Kronenberger explained in a statement. "The raw material, silk dope, is funneled through exceptionally narrow and long ducts into tiny spinning nozzles or spigots. Importantly, the silk seems to form only just before it emerges at the uniquely-shaped spigots of this spider."

However, what makes these dry webs "sticky" enough to hold onto insects is actually static electricity. As the silk is produced, the spider violently combs and hacks at the threads with the feather-like hairs on their hind legs.

"The extreme thinness of each filament, in addition to the charges applied during spinning, provides Van der Waals adhesion. And this makes these puffs immensely sticky," added Fritz Vollrath, who was also involved in the study.

The researchers theorize that not only does this dry stickiness catch prey, but it also helps hold incredibly thin and complex webs together.

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