Evolutionary analysis of a predator–prey community under natural and artificial selections

Abstract

This paper investigates the evolutionary impacts of size-selective harvesting and size-dependent competition in predators on an evolving trait of predator individuals (e.g. body size and maturation age) in a predator–prey model. By using population dynamics and adaptive dynamics, we obtain the evolutionary conditions allowing for evolutionary branching and continuously stable strategy under asymmetric competition in predators for natural selection and size-dependent harvesting for artificial selection. The evolution of polymorphism is explored by numerical analysis and simulations. It is shown that high levels of sequence polymorphism may work up during adaptive evolution that leads to biological diversity. First, increase in competition among predators can result in rapid evolution towards larger body size or maturation age, but harvesting has an opposite effect. Second, competition can make for evolutionary branching, while harvesting can go against evolutionary branching and promote evolutionary stability. Last, from an evolutionary point of view, that competition can promote species diversity among predator populations, however, harvesting has an opposite effect.