The Elasticity of Spiders' Webs is Due to Water-Induced Mobility at a Molecular Level

¹³C nuclear magnetic resonance (NMR) spectroscopy of intact webs from the common garden spider Araneus diadematus has been used to demonstrate that: (i) water retention is an important role for the viscid coating of capture thread; (ii) the elasticity of capture thread results from water-induced mobility at a molecular level, (iii) the organization and composition of structural and capture thread are different, even in the absence of coating; and (iv) glycoproteins may have a more important presence and structural role than previously realized. Different ¹³C-labelling patterns of webs were achieved by feeding spiders either with [¹³C]glucose or with [¹³C]amino acids.