We present a periodic nonlinear scalar delay differential equation model for a population with short reproduction period. By transforming the equation to a discrete dynamical system, we reduce the infinite dimensional problem to one dimension. We determine the basic reproduction number not merely as the spectral radius of an operator, but as an explicit formula and show that is serves as a threshold parameter for the stability of the trivial equilibrium and for permanence.
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The function
Solutions of (1.1) with periodic Ricker-type birth function for different values of parameter
Solutions of (1.1) with periodic Beverton–Holt-type birth function for different values of parameter