A simulation study of mechanisms of group selection of the slime mold Dictyostelium discoideum

Slime molds are fascinating organisms, they can either live as an organism consisting out of a single cell (protozoa) or they can form a multi-cellular organism (pseudoplasmodium). So from the biological point of view, the slime molds are studied in order to understand the evolutionary step from a single cell organism to a multi-cellular organism. Studies have shown that the behavior of cooperating single cell organisms exhibit synergistic emergent intelligence, for example finding shortest paths. Just recently, simulation and experiments with a real slime mold (Physarum polycephalum) have been used for traveling salesman like problems. In this work we present a simulation model for the slime mold Dictyostelium discoideum. Different to other studies, here the whole life-cycle is modeled and simulated. This model is used to study the mechanism of cooperation of single cells: We compare the mechanism of altruistic group selection against individual and egoistic selection. It turns out that simple signaling mechanisms are sufficient for a complex behavior of Dictyostelium discoideum, that allows altruistic behavior on cell level, helping the whole population to survive.