Biased Lévy-walk pattern in the exploratory behavior of the Physarum plasmodium

The plasmodium of Physarum polycephalum is a unicellular and multinuclear giant amoeba. The plasmodium has the ability to sense and adapt to many kinds of environmental stimuli, and its optimization behavior in closed spaces has been analyzed extensively. However, few studies have tested the behavior of the plasmodium in an open spaces, despite the biological importance of the adaptability of biological entities in such conditions. Accordingly, we established an experimental setup with a very large and strictly homogeneous substrate and observed the long-term exploratory behavior of the plasmodium. As a result, we found that the movement of the plasmodium was consistent with a Lévy-walk, but with anisotropic bias.