HOPF BIFURCATION FOR A PREDATOR-PREY MODEL WITH AGE STRUCTURE AND RATIO-DEPENDENT RESPONSE FUNCTION INCORPORATING A PREY REFUGE

In this paper, a predator-prey model with age structure and ratio dependent response function incorporating a prey refuge is investigated. The model is formulated as an abstract non-densely defined Cauchy problem and a sufficient condition for the existence of the positive age-related equilibrium is given. Then using the integral semigroup theory and the Hopf bifurcation theory for semilinear equations with non-dense domain, it is shown that Hopf bifurcation occurs at the positive age-related equilibrium. Numerical simulations are performed to validate theoretical results and sensitivity analyses are presented. The results show that the prey refuge has a stabilizing effect, that is, the prey refuge is an important factor to maintain the balance between prey and predator population.