We analyzed berry production in rowan, Sorbus aucuparia L., in southern Norway and examined the ramifying effects of rowan masting on the dynamics of the dominant seed predator and its parasitoid. The apple fruit moth, Argyresthia conjugella Zeller, is a pre-dispersal seed predator of rowan. The larva of the apple fruit moth rely on rowan berries, which in turn is attacked by the parasitoid wasp, Microgaster politus Marsh. We found classic masting in rowan: berry production varied across years (the mean coefficient of variation=1.02) and was spatially synchronized at large scale (the averaged correlation coefficient=0.67). Berry production represented a two-year cycle in western but a three-year cycle in eastern Norway. The abundance of the moth and the parasitoid also varied across years and were spatially synchronized. The degree of spatial synchrony decreased and cyclicity became obscure with increasing trophic level. We attempted to assess two different components to the predator satiation, functional and numerical satiations, based on a simple population dynamics model. The observed pattern of seed predation testified that both of functional and numerical satiations were at work in this system. In a comparison at different locations, rowan trees with more variable berry production were more effective in reducing losses to the seed predator. The parasitoids also seemed to experience satiation through the fluctuation in their host abundance. These results show that rowan masting has an adaptive foundation, which impacts the dynamics of higher trophic levels. Nutrition; Diet; Parasites diseases and disorders; Parasites; Insect parasites; Hosts; Insect hosts; Ecology; Land zones; Palaearctic region; Eurasia; Europe Argyresthia conjugella (Argyresthiidae); Food plants; Sorbus aucuparia; Plant masting cycle, trophic cascade effects in seed predator & hymenopteran parasitoid populations; Food availability; Hymenopteran parasites; Microgaster politus; Trophic cascade effects of food plant masting on seed predator & parasitoid populations; Trophic structure; Population dynamics; Norway; South; Trophic cascade effects of food plant masting on seed predator & hymenopteran parasitoid populations Microgaster politus (Braconidae); Lepidopteran hosts; Argyresthia conjugella; Trophic cascade effects of plant masting on seed predator & parasitoid populations; Trophic structure; Population dynamics; Norway; South; Trophic cascade effects of plant masting on lepidopteran seed predator hosts & parasite populations none