Biomechanics of the slingshot spider and its three-dimensional web

A three-dimensional model for the release dynamics of a category of orb web spiders is developed. The web response depends on the material properties of the web silk and its geometric layout. A detailed aerodynamic damping analysis is provided for webs operating in still air. The web is assumed to operate at strain values below the web material yield point and also to remain in tension throughout transient operation. The spider is faced with a multidimensional optimisation problem that involves balancing the need for a fast web response and manageable web-material forces. Other issues, not discussed, include the protection of the web from prey-impact and wind-related damage. It is shown that the aerodynamic damping of the web is dominated by the concentric capture fibres.