Ethology and rheology of an amoeba
- Behavioral diversity and decision-making in Physarum -
中垣 俊之 教授
A diversity of behavioral types is apparent even in primitive organisms. But what is known about how it emerges is still limited. As decision-making is choice of an action from multiple possible options of behaviors, it is biologically meaningful if the option shows a wide variety. In this report, an amoeboid organism of Physarum plasmodium (true slime mold) can show three major types and almost twenty subtypes of behaviors when encountering a weakly toxic zone. We propose a dynamical mechanism for emergence of such behavioral diversity, according to already proposed equations of rheological motion for the amoeboid movement. The dynamical mechanism is expected to be robust against still-on-going discussion on model justification for the real Physarum since the mathematical essence is common and generic. We conclude that behavioral diversity and decision-making are two sides of one thing. The results obtained here are on a unicellular organism but the similar mechanism might be shared by higher animals.