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We report on three launches of ballooning $Erigone$ spiders observed in a 0.9 m$^3$ laboratory chamber, controlled under conditions where no significant air motion was possible. These launches were elicited by vertical, downward-oriented electric fields within the chamber, and the motions indicate clearly that negative electric charge on the ballooning silk, subject to the Coulomb force, produced the lift observed in each launch. We estimate the total charge required under plausible assumptions, and find that at least 1.15 nC is necessary in each case. The charge is likely to be non-uniformly distributed, favoring initial longitudinal mobility of electrons along the fresh silk during extrusion. These results demonstrate for the first time that spiders are able to utilize charge on their silk to attain electrostatic flight even in the absence of any aerodynamic lift.
We analyze the wide angle x-ray scattering from oriented spider silk fibers in terms of a quantitative scattering model, including both structural and statistical parameters of the $beta$-sheet crystallites of spider silk in the amorphous matrix. The
Spider silk possesses unique mechanical properties like large extensibility, high tensile strength, super-contractility, etc. Understanding these mechanical responses require characterization of the rheological properties of silk beyond the simple fo
Much evidence seems to suggest cortex operates near a critical point, yet a single set of exponents defining its universality class has not been found. In fact, when critical exponents are estimated from data, they widely differ across species, indiv
Spectacular collective phenomena such as jamming, turbulence, wetting, and waves emerge when living cells migrate in groups.
We study unbinding of multivalent cationic ligands from oppositely charged polymeric binding sites sparsely grafted on a flat neutral substrate. Our molecular dynamics (MD) simulations are suggested by single-molecule studies of protein-DNA interacti