When I was a master student, I came across a paper showing that forest and stream ecosystem seasonally subsidize each other (Nakano & Murakami 2001 PNAS). Even today-10 years later, it is the most beautiful paper that I have ever read. In the meanwhile, I luckily found that a parasite (Nematomorph) drives strong seasonal subsidy for trout in the form of terrestrial insects that are manipulated by the parasite in mountainous streams in Japan. On the basis of the Nakano’s paper and my own field observation, I am now studying how stream salmonids and their communities live in seasonal environments. We conducted field experiments, in which we directly altered peak timing of the terrestrial insect inputs into streams, in Canada and Japan. In both experiments, we found that subsidies occurring at the early in the growing season can have pronounced effects on trout’s growth trajectory and age at maturity, compared with the subsidies occurring at the latter season. I would discuss how we could integrate this timing-dependent consumer response into a general framework to understand dynamics of populations and communities in seasonally interacting ecosystems.