Main Content

The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Ref ID : 1786

Bruce R. Levin, Frank M. Stewart, and Lin Chao; Resource-limited growth, competition, and predation: A model and experimental studies with bacteria and bacteriophage. The American Naturalist 111:3-24, 1977

Reprint

In File

Notes

In a recent article and monograph, May (1972, 1973) has demonstrated that many of the models of predator-prey interactions used by ecologists have solutions specifying stable equilibrium points or stable limit cycles. These theoretical results are extremely significant. In the models considered by May, the interacting populations exist in homogeneous habitats. Consequently, it is not necessary to invoke spatial or temporal heterogeneties or nonattainment of equilibria to account for the coexistence of predators and their prey. The models studied by May are, however, nonspecific. The species growth and interactions are described simply as functions of their respective densities. The nature of the habitat, the relationships between the primary resources, and the growth of the prey populations are not specified. Neither is the form of the predation. Consequently the factors responsible for stabilizing the equilibria or limit cycles are described primarily in terms of the properties of the equations rather than in terms of the biology. As a results, this theory is of limited utility for predicting when there will be stable states of coexistence in a given predator-prey situation. Campbell (1961) studied the predator-prey association between bacteria and their viruses. His models were developed from a consideration of the biology of the interacting species, but were not very specific about the nature of the habitat and took no account of the relationship between prey growth and the availability of primary resources. In this investigation, we present models of this bacteriophage-bacteria interaction which are based on specific assumptions about the habitat, the use of primary resources, the population growth, and the nature of the interaction between predator and prey. We consider conditions for equilibria and demonstrate that on a priori grounds, stable states of coexistence are to be anticipated. We then compare the behavior of these models with that of experimental populations of Escherichia coli and its virulent virus T2.