Prey Localization in Spider Orb Webs Using Modal Vibration Analysis

Spider webs are fnely tuned multifunctional structures, widely studied for their prey capture functionalities such as impact strength and stickiness. However, they are also sophisticated sensing tools that enable the spider to precisely determine the location of impact and capture the prey before it escapes. In this paper, we suggest a new mechanism for this detection process, based on potential modal analysis capabilities of the spider, using its legs as distinct distributed point sensors. To do this, we consider a numerical model of the web structure, including asymmetry in the design, prestress, and geometrical nonlinearity efects. We show how vibration signals deriving from impacts can be decomposed into web eigenmode components, through which the spider can efciently trace the source location. Based on this numerical analysis, we discuss the role of the web structure, asymmetry, and prestress in the imaging mechanism, confrming the role of the latter in tuning the web response to achieve an efcient prey detection instrument. The results can be relevant for efcient distributed impact sensing applications.