This proceeding is a compilation of findings and progress activities of research collaboration between the Forest Department Sarawak (FDS) and the Japan Research Consortium for Tropical Forests in Sarawak (JRCTS). To highlight the research findings, An International Symposium entitled "Frontier in Tropical Forest Research: Progress in Joint Projects between the Forest Department Sarawak and the Japan Research Consortium for Tropical Forests in Sarawak" was ii held in Kuching, Sarawak on 21-22 September 2015.Insect seed predators play important roles in the dynamics of forest ecosystems. Here, we briefly review the recent progress of research in ecology and evolutionary biology of insect seed predators in Southeast Asian tropical rainforests, where community-wide supra-annual masting (called "general reproduction (GR)" here) occurs, with the introduction of the predator satiation hypothesis, which is one of the leading hypotheses to explain the ecological mechanisms promoting the evolution of GR. We also introduce our own current studies on insect seed predators in the lowland tropical rainforest at Lambir Hills National Park, Sarawak. In addition, we present our future plans for research on the natural history and evolutionary ecology of interactions between seed-feeding insects and plant species in Sarawakian tropical rainforests, with emphasis on the necessity for the long-term census on the community-level seed predation.