A Comparison of the Swarm Behavior of Whirligigs with a Computer Simulation Model

Whirligig Beetles (Gyrinidae) make a useful experimental system to test hypotheses relating to the general movement of grouped animals.  Individually based simulation models of groups are also helpful in trying to understand the emergent properties of groups including the way humans leave buildings during an emergency.  However, only rarely are simulation models and experimental work directly compared.  In this study we tested how four different door shapes influence the speed at which a group of individuals escape from an enclosure.  Overall door space was kept equal and two different group sizes were used.  Empirical results were then compared to an individually based computer simulation model that we created based on the general movement patterns of whirligig beetles (with movement functions based on factors such as: attraction, repulsion, speed, momentum, and viewing distance).  The whirligig experiments resulted in the finding that two of the door positions trapped individuals inside significantly more often than other door positions.   For the simulation model study, only one of these door types was significantly harder to escape from than the other three.  Comparisons between the experimental and simulation data will help us to refine this simulation model.  A tested simulation model of how swarms escape enclosed spaces will help to design exits for other gregarious species including schools, flocks, and panicked crowds of people.