Continuous Single-Species Population Models with Delays

Abstract

Up to now in our study of continuous population models we have been assuming that x′(t), the growth rate of population size at time t, depends only on x(t), the population size at the same time t. However, there are situations in which the growth rate does not respond instantaneously to changes in population size. One of the first models incorporating a delay was proposed by Volterra (1926) to take into account the delay in response of a population’s death rate to changes in population density caused by an accumulation of pollutants in the past.