12. Modeling Transverse Vibration in Spider Webs Using Frequency-Based Dynamic Substructuring

Orb weaving spiders and their webs have co-evolved into a highly efficient prey capture and retention system. Spiders also use their web as a sensory extension by “listening” to vibrations transmitted across the web such as struggling prey trapped in the web, courtship from potential mates, or the advance of a predator. What information is available to orb weaving spiders from web vibrations, and how might this information be used for localization and identification of cues? To better understand the information available to the spider in its web, we created both physical and computational models of spider webs. Enlarged, artificial webs suitable for physical measurements (1.2 m in diameter) were constructed from two types of parachute cord to mimic the different silks used by spiders in web construction. Accelerometers placed around the center of the web measured the vibration response of the artificial web. We formed a model for large networks of transversely vibrating strings, such as a web, using Frequency Based dynamic Substructuring (FBS). From the FBS model, we generated frequency response functions at locations corresponding to typical foot placements of orb weaving spiders for vibration sources at various points in the web. We explored the influence of web architecture on web frequency response by altering web composition, pre-tension, and geometry. Frequency response features sensitive to stimulus location were also identified from the FBS model. Our research indicates that localization of both bearing and range for a vibration stimulus is possible in the modeled webs.