An optimization principle for initiation and adaptation of biological transport networks

Structural optimization of biological transport networks, such as leaf venation and blood vessel systems, can be regarded as a consequence of natural selection. Many studies have examined the important question of whether an adaptation dynamics of edges can be responsible for structural optimization. However, what role the initiation process plays in structural optimization remains to be clarified. Here we propose an optimization principle that potentially underlies common mechanisms that drive the formation of biological transport networks. Associated with the optimization principle is an adaptation dynamics of cell polarization that unifies initiation processes and segment formation of transport networks. In our model, the competition between the reduction of transport energy cost and the reduction of material and metabolic consumptions is sufficient to induce optimal structures: a tree-like network as well as loops under different states of fluctuating drives.