Population Development and Interactions Between Two Species of Bacteriophagic Nematodes

The population dynamics on agar cultures of two species of bacterial-feeding soil nematodes are described. Mesodiplogaster lheritieri populations develop rapidly because they produce eggs early and have a short generation time (4 days). Although Acrobeloides sp. has a longer generation time (11 days), it also has a longer reproductive period. These nematodes respond differently to adverse conditions. Acrobeloides produces an anabiotic form resistant to predation, food limitation, and desiccation. M. lheritieri produces dauer larvae or intrauterine juvenile, primarily in response to food shortages. Because M. lheritieri is potentially predatory, it has an advantage when the two species compete. The reproductive strategies of, and food utilization by, the nematodes represent distinctly different grazing patterns in the nematodes.