Metapopulation dynamics in an aphid-parasitoid system

摘要: Metapopulation theory makes a number of predictions concerning the effects dispersal on persistence predator-prey or host-parasitoid systems. While stabilising have been shown in laboratory studies, evidence from field studies remains scarce due to lack suitable model I describe system that shows classical metapopulation structure with frequent extinctions and colonisations consisting aphidiid Lysiphlebus hirticornis aphid Metopeurum fuscoviride. Both parasitoid are specialists their respective hosts. followed dynamics host individually marked tansy (Tanacetum vulgare) plants, M. Dynamics populations were characterized by colonisations. Mean longevity colonies was only 3.1 weeks. Parasitism L. main cause extinction for as rates parasitism often reached 100%, particular towards end season. Patchiness this occurs at two spatial scales. Aphid form single ramets = shoots but movements individuals among within genet frequent. Because aphids can persist large numer generations, it is argued local genets rather than ramets. The described study exceeds usually observed metapopulations. It suggested aphid-parasitoid systems such one studied paper may be good models test theory.