Indirect Allee Effect, Bistability and Chaotic Oscillations in a Predator-Prey Discrete Model of Logistic Type

Abstract

A cubic discrete coupled logistic equation is proposed to model the predator-prey problem. The coupling depends on the population size of both species and on a positive constant $\lambda$, which could depend on the prey reproduction rate and on the predator hunting strategy. Different dynamical regimes are obtained when $\lambda$ is modified. For small $\lambda$, the species become extinct. For a bigger $\lambda$, the preys survive but the predators extinguish. Only when the prey population reaches a critical value then predators can coexist with preys. For increasing $\lambda$, a bistable regime appears where the populations apart of being stabilized in fixed quantities can present periodic, quasiperiodic and chaotic oscillations. Finally, bistability is lost and the system settles down in a steady state, or, for the biggest permitted $\lambda$, in an invariant curve. We also present the basins for the different regimes. The use of the critical curves lets us determine the influence of the zones with different number of first rank preimages in the bifurcation mechanisms of those basins.