Colloquia

Theories of swarming and pattern formation have recently become of interest to engineers, chemists and physicists. Interesting examples are offered by various self-propelled biological agents both in simulations and in reality. But well-defined swarming experiments in the lab using real biological agents have been problematic up to now due to size limitations of the animal groups or lack of precise knowledge of the agent-agent or agent-medium interactions. We present the results of lab experiments with the zooplankton /Daphnia/, or “water flea” ­ intermediate in size and complexity between bacteria and birds or fish, for example. Our experiments are compared to predictions of the “Active Brownian Particle” theory developed by a group at Humboldt University in Berlin. /Daphnia/ show the entire range of the theoretically predicted behaviors from single agent to collective motions of swarms and can be observed to perform a fascinating bio-hydrodynamic vortex under certain conditions.