Nonconstant periodic solutions in predator-prey systems with continuous time delay

Abstract This paper combines previously developed models and results for predator-prey systems with continuous time delay by Volterra, Bownds, Cushing, MacDonald, Worz- Busekros, and others. We present an analytic nonconstant periodic solution in the case that the integral kernel is the function ae −at by making use of the fixed-point theorem.