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Article Title

Selective Pressure on Predator and Prey When an Age Class Becomes a Refuge from Predation

Volume

76

Issue

3

First Page

173

Last Page

185

Abstract

A Lotka-Volterra predator-prey model, in which a sexually immature and a sexually mature age class exists, is studied in order to discover the effects on the system of an age class refuge from predation. Prey density-dependent effects are also considered. This refuge situation was found to be advantageous, in terms of group selection for predator and prey, but individually disadvantageous for predators. Prey density dependence reduces the likelihood of an equilibrium between predator and prey populations, but also reduces the necessary criteria for local stability when an equilibrium point exists. A method for the initial occurrence of group selection is suggested.