Food Competition Among the Cellular Slime Molds (Acrasieae)

Four species of Acrasieae (Dictyostelium mucoroides, D. purpureum, Polysphondylium pallidum, and P. violaceum) coexist in forest soils. All are capable of feeding and reproducing on a wide variety of bacteria than exist in their habitat. The four Acrasieae and four strains of food bacteria were isolated from the soil. When the four slime molds were forced to compete on a single strain of bacteria, one species always outcompeted the others. For any particular food the same species of Acrasieae is the consistent winter. Each species uses a different strategy to outcompete its competitors. The consistency of competitive success and the coarse—grained nature of the food distribution allow the coexistence of these four species of Acrasieae in nature.