Single species dynamics in changing environments

Abstract

A priori bounds are obtained for positive solutions of scalar delay differential equations of the form

modelling single species dynamics in a temporally changing environment. Sufficient conditions are derived for the existence of periodic and almost periodic solutions when fis aperiodic and almost periodic function respectively in t.Applications of our analysis enable the derivation of known results in Gopalsamy et al. (1994), Gopalsamy and Ladas (1990), Ladas and Qian (1993) and Lalli and Zhang (1994) as special cases.