Its unique mechanical properties make spider silk well-suited to the capture of prey. Orb webs capture prey by dissipating kinetic energy of prey; therefore, high strain and low resilience are important properties of the silk. Cobwebs capture prey with thread breakage and entanglement; therefore, other properties may be more important. Studies reveal that orb web silks consists of proteins arranged in anti-parallel beta sheets. X-ray diffractions reveal orderly crystal regions interspersed with amorphous regions. Silks of different functions from the same web consist of similar proportions of amino acids, yet differ significantly in mechanical properties. It has been suggested that the amorphous regions play a role in determining mechanical properties of spider web. Given these differences in types of orb web silk threads from a single web, we expect to find different structural properties in the cobweb. We present our progress in measuring the structural properties of the cobweb of the black widow spider, Lactradectus mactans, at the molecular level. Our initial results consist of high resolution atomic force microscope (AFM) images of the thread.
Quasistatic and continuous dynamic characterization of the mechanical properties of silk from the cobweb of the black widow spider Latrodectus hesperus
