The migration stage of Dictyostelium: Behavior without muscles or nerves

The migrating slug of the cellular slime mould, Dictyostelium discoideum is capable of directed movement. A rather large literature on how this simple group of amoebae move and orient is briefly summarized. All the amoebae in the slug move, and their internal direction is controlled by chemotaxis, by relay waves of cAMP that start at the anterior tip. This moving mass of amoebae can be oriented by directional light, as well as heat and chemical gradients. Such external factors could orient by shifting the position of the cAMP pulse pacemaker in the tip, or by making the cells move faster or slower on one side of the anterior portion of the slug, or a combination of the two.