Active Decentralized Transport in Biological Networks

Supply networks are essential for transport in living systems, such as blood flow and fungal mycelia, or in human made systems, such as power grids and sewage systems. Many transport systems use centrally controlled pumps to disperse their resources. In contrast, we study the slime mold Physarum polycephalum, which employs a decentralized strategy to disperse nutrients, transport mass, and propagate signals across its networked body. The decentralized strategy is driven by a network of elastic tubes that rhythmically contract and expand to shuttle cytoplasmic flow. While this mechanism has been studied for single tubes, no full network study has been conducted. In this work, we combine experimental data from real Physarum networks with simulations of the active mechanism that drives flow. We find that the model predicts excitation of contractile modes that span the entire network in agreement with our data. Beyond the understanding of Physarum, our results could be used to design other decentralized transport infrastructures.