Spider major ampullate (MA) silk is nature’s toughest materials . Accordingly, there is considerable interest in the creation of materials that mimic its performance . Nevertheless, attempts to recombine, amplify and spin spider silk proteins have not produced fibers with properties resembling those of naturally spun silk . One reason for the inability to produce such fibers is that the properties of MA silk are highly variable and the mechanisms inducing this variation have never been delineated from nano to macro scales .