Behavioral Ecology doi:10.1093/beheco/arq118 Advance Access publication 00 Month 2010 Determining interaction rules in animal swarms

In this paper, we introduce a method for determining local interaction rules in animal swarms. The method is based on the assumption that the behavior of individuals in a swarm can be treated as a set of mechanistic rules. The principal idea behind the technique is to vary parameters that define a set of hypothetical interactions, as for example, a rule for aligning with neighbors. The parameter values are optimized so that the deviation between the observed movements in an animal swarm and the movements predicted by the assumed rule set is minimal. We demonstrate the method by reconstruct-ing the interaction rules from the trajectories produced by a computer simulation. Key words: behavioral rules, force matching, reverse engineering, swarming. [Behav Ecol 21:1106–1111 (2010)] The collective motion of living organisms, as manifested byflocking birds, schooling fish, or swarming insects, presents a captivating phenomenon believed to emerge mainly from local interactions between individual group members. In part, the study of swarming and flocking aims to understand how animals use visual, audial, and other cues to orient them-selves with respect to the swarm of which they are part and how the properties of the swarm as a whole depend on the behaviors of the individual animals. Also when addressin