By varying the conditions under which the spiders were kept (different reeling speeds, starvation periods), the species or the spiders inside the same species, it has been seen that
dragline silk has different mechanical properties and varies on an interspecific, intraspecific and intra-individual level [23].
Spider
dragline silk was tested in a wet environment to show that moisture induces supercontraction in the threads for levels higher than 70 — 75 % of relative humidity, proving that when a thread is exposed to moisture, stresses quickly build up and tighten the thread [20].
They saw that Nephila clavipes
dragline silk had almost double the final stress value compared to the same silk of Araneus gemmoides, whilst the minor ampullate silk had roughly the same final stress value [34].
To begin a web, a spider anchors a strand of
dragline silk — three times stronger than the Kevlar in bulletproof vests — and waits for a breeze to blow it to a second attachment point.
STRONG START Molecular biologists at the University of Wyoming are planning to use the proteins from superstrong
dragline silk to build artificial tendons and ligaments.
Spider silk proteins and methods for producing spider silk proteins
Dragline silk is the toughest kind of spider silk.
For example, what math was used to calculate the capability of
dragline silk from an orb weaver spider that is lighter than cotton, yet ounce for ounce stronger than steel, tougher than kevlar (used in bullet - proof vests), that if the silk were 0.4 inch thick with strands 1.6 inches apart and enlarged the size of a football field, could stop a jumbo jet in flight, that is flying at an average speed of about 600 mph?
Stretched enough, the protein molecules snap into different arrangements, becoming stronger and tougher, and more akin to spider
dragline silks and high performance synthetics like Kevlar, Fudge said.
Not exact matches
The lab is working with
silk that the spider uses for
draglines (dropping off into space) and the long segments of its web.
Researchers had already identified two genes for the class of
silk known as major ampullate, which forms the superstrong
dragline threads that anchor webs and are the inspiration for a major effort to make spider
silk commercially (see p. 293).
Quite unexpectedly, the researchers found that females had no interest in the
draglines that males produced, nor the
silk that they used to wrap nuptial gifts in.
It has been demonstrated that
silk properties (in terms of different reeling methods [32], [42], environmental conditions [8], [20], types of
silk [e.g.
dragline, viscid or egg sac
silk][22], [24], [34]-RRB- are species - specific and lead to
silk - based peptide fibrils or protein aggregates with different structural and mechanical properties.