Leroy Apker Award Winner: Adam Dionne

Active fluid transport is a hallmark of many biological transport networks. While animal circulatory systems generally rely on a heart to drive flows, other organisms employ decentralized local pumps to distribute fluids and nutrients. We study one such organism, the slime mold Physarum polycephalum. Based on a network model combining active elasticity and fluid transport, we identify a set of contractile modes specific to each network topology. Modes corresponding to large-scale oscillations are found to be preferentially and robustly excited in both model simulations and in experimental data obtained from living Physarum plasmodia. These dominant modes are computed explicitly and shown to drive large-scale flows within the organism. We go on to use these modes to decompose Physarum’s behavior when studying a specific behavior of the network, nutrient transport. We characterize the modal composition that optimizes for nutrient dispersal throughout the network by using transport simulations. These results provide a conceptual framework for understanding active decentralized transport in Physarum and other contractile biological networks such as the brain vasculature, and decentralized transportation networks more generally.