摘要: Population cycles are one of nature9s great mysteries. For almost a hundred years, innumerable studies have probed the causes cyclic dynamics in snowshoe hares, voles and lemmings, forest Lepidoptera grouse. Even though species very different life histories, similarities mechanisms related to their apparent. In addition high reproductive rates density-related mortality from predators, pathogens or parasitoids, other characteristics include transgenerational reduced reproduction dispersal with increasing-peak densities, genetic similarity among populations. Experiments stop comparisons noncyclic populations provide some understanding but both must be considered. What determines variation amplitude periodicity population outbreaks remains mystery.