From Stability to Chaos : analyses on niche separation and population processes generating chaotic dynamics in 1 host-2parasitoid systems

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Complicated population dynamics were investigated in systems of seed beetle hosts and parasitoid wasps. We analyzed effects of hosts' spatial distribution and parasitoids' niche separation for the host stages on population dynamics, based on numerical simulations for experimental systems. We founded resource-clumped systems in which vulnerable hosts were located in one large resource patch and resource-sparse one where those hosts were divided into 16 small patches. The resource-clumped condition showed larger mean population sizes with smaller population fluctuations than the resource-sparse condition did, which suggests the former has more higher population persistence than the latter.Furthermore, numerical simulations for these experimental systems with the three species showed that the larger the parasitoids' niches separate, the larger a region of parametric values for stable coexistence became. Chaotic population behaviors with non-equilibrium dynamics resulted in persistence of the component species in the systems. All these results showed the limiting similarity theory can be supported in non-equilibrium dynamics.