The persistence of host-parasitoid associations in patchy environments I. A general criterion

For host-parasitoid interactions in a heterogeneous environment and with discrete generations, the dynamic effects of any patterns of distribution of searching parasitoids can be assessed within a common, simple framework. The populations are regulated if the distribution of searching parasitoids is sufficiently heterogeneous. The square of the coefficient of variation (CV²) of the searching parasitoids per host must exceed unity. CV² may be partitioned into a density-dependent component caused by the response of parasitoids to host density per patch and a density-independent component. Population regulation is enhanced as much as density-independent as by density-dependent heterogeneity. -from Authors