Dynamics on the spider web: biological agents use physical rules to solve complex tasks

  Amir Haluts [1]  ,  Sylvia F. Garza Reyes [2, 3]  ,  Dan Gorbonos [1, 3]  ,  Alex Jordan [2, 3]  ,  Nir S. Gov [1]  
[1] [1] Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot 7610001, Israel
[2] [2] Max Planck Institute of Animal behaviour, Konstanz 78315, Germany
[3] [3] Centre for the Advanced Study of Collective Behaviour, University of Konstanz, Konstanz 78457, Germany

A long-standing question in animal behaviour is how organisms solve complex tasks. Here we explore how the dynamics of behaviour in the ubiquitous tasks of mate-search and competition can arise from a physics-based model of effective interactions. Male orb-weaving spiders of the genus Trichonephila are faced with the daunting challenge of entering the web of a much larger and potentially cannibalistic female, approaching her, and fending off rival males. Within the confined arena of the female’s web, their dynamics are dominated by seismic interactions. This unifying modality allows us to describe the spiders as interacting active particles, responding only to effective forces of attraction and repulsion. Through the emergent dynamics of ’spider particles’, we explain a puzzling relationship between the reproductive advantages of large males and the density of males on the web. Our results provide strong evidence that simple physical rules can give rise to complex fitness related behaviours.