We report here evidence that an effective transportation network is designed by an amoeba-like organism of
true slime mold Physarum polycephalum,
which has network of tubes to transport chemical materials all through the organism. When many food-sources
were distributed on an agar plate where
the organism crawled, the organism found them and changed the network shape to connect the food-sources
through only a few tube. Geometrical shape of
the network is drastically variable depending on a set of locations of food-source. Statistical observation
shows that the network geometry meets
multiple requirements for effective network; short total length of tubes, close connection (small number of
transit food-sites between any two
food-sites) and fault-tolerance against an accidental disconnection of tubes. Local self-sustained cellular
rhythms interact each other in the
organism and pattern formation of the cellular rhythm underlie in mechanism of development of tube-network.
Along this line, a mathematical model for
self-organization of transport network is proposed and discussed.
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