Approximating Mexican highways with slime mould

TL;DR

This study investigates how the foraging network of Physarum polycephalum mimics the Mexican highway system, suggesting bio-inspired approaches to road planning based on laboratory experiments with living slime mold.

Contribution

It demonstrates that Physarum's protoplasmic networks can approximate the structure of Mexican highways through experimental modeling.

Findings

Physarum networks are isomorphic to Mexican highway networks

Laboratory experiments show structural similarities between slime mold and roads

Bio-inspired models could inform future road planning strategies

Abstract

Plasmodium of Physarum polycephalum is a single cell visible by unaided eye. During its foraging behavior the cell spans spatially distributed sources of nutrients with a protoplasmic network. Geometrical structure of the protoplasmic networks allows the plasmodium to optimize transport of nutrients between remote parts of its body. Assuming major Mexican cities are sources of nutrients how much structure of Physarum protoplasmic network correspond to structure of Mexican Federal highway network? To find an answer undertook a series of laboratory experiments with living Physarum polycephalum. We represent geographical locations of major cities by oat flakes, place a piece of plasmodium in Mexico city area, record the plasmodium's foraging behavior and extract topology of nutrient transport networks. Results of our experiments show that the protoplasmic network formed by Physarum is isomorphic, subject to limitations imposed, to a network of principle highways. Ideas and results of the paper may contribute towards future developments in bio-inspired road planning.