Compounds in the droplets of the orb spider's viscid spiral

• DOI: 10.1038/345526a0
• Publication Date: 2003-06-12T22:43:00Z
• Authors: Fritz Vollrath; Wayne J. Fairbrother; Robert J. P. Will...; Edward K. Tilling...; David T. Bernstein; Kathleen S. Galla...; Mark A. Townley
• Keywords: Orb (optics); Spider Silk

THE orb web of the garden spider Araneus diadematus, like those of other ecribellate orb spiders, relies on the remarkable extensibility of its sticky capture spiral to intercept and entrap prey1,2. The spiral strands consist of core fibres and an all-enveloping aqueous coat, which forms into a pattern of droplets3. The core fibres are paired and probably made of typical spider silk4,5. The aqueous solution droplets are more or less evenly spaced6 and are required to allow the special mode of extension of the fibres3,7. Knowledge of the chemical composition and general physical properties of this liquid phase is necessary to understand its function in web mechanics and prey capture8. We have now investigated the chemical composition of this aqueous solution and found the droplets to be a concentrated solution of hygroscopic substances related to neurotransmitters. We offer an explanation as to the function and origin of this solution.