Size-dependent self-avoidance enables superdiffusive migration in macroscopic unicellulars

TL;DR

This study reveals that the giant slime mold Physarum polycephalum achieves superdiffusive migration through size-dependent self-avoidance, which may offer evolutionary advantages by enhancing search efficiency.

Contribution

The paper introduces a data-driven model explaining how size-dependent self-avoidance leads to superdiffusive movement in Physarum polycephalum, linking cell size to migration behavior.

Findings

Physarum exhibits superdiffusive migration via self-avoiding run-and-tumble behavior.

Food presence alters short-term run duration but not long-term superdiffusion.

Larger organism size enhances superdiffusive search efficiency.

Abstract

Many cells face search problems, such as finding food, mates or shelter, where their success depends on their search strategy. In contrast to other unicellular organisms, the slime mold Physarum polycephalum forms a giant network-shaped plasmodium while foraging for food. What is the advantage of the giant cell on the verge of multicellularity? We experimentally study and quantify the migration behavior of P. polycephalum plasmodia on the time scale of days in the absence and presence of food. We develop a model which successfully describes its migration in terms of ten data-derived parameters. Using the mechanistic insights provided by our data-driven model, we find that regardless of the absence or presence of food, P. polycephalum achieves superdiffusive migration by performing a self-avoiding run-and-tumble movement. In the presence of food, the run duration statistics change, only controlling the short-term migration dynamics. However, varying organism size, we find that the long-term superdiffusion arises from self-avoidance determined by cell size, highlighting the potential evolutionary advantage that this macroscopically large cell may have.