Seed predation by insects have considerable influences on plant reproduction and food web structures in forest ecosystems. Furthermore, various insect species have evolved to prey on plant seeds as their main food in tropical rainforests. However, few studies have attempted to elucidate details of patterns of seed utilization by insect seed predators in South-east Asian lowland dipterocarp forests, where many plant species reproduce only when community-wide reproducing event occur at supra-annual irregular intervals. We investigated spatially and temporally dynamic patterns of seed utilization by seed-eating insects during three mast fruiting following general flowering during the periods of community-wide reproducing events that occurred in 2013, 2014 and 2019 in Lambir Hills National Park located in the north-western Borneo. In this talk, we will introduce results of our studies on differences in seed utilization patterns and intensity of seed predation among several insect species preying on dipterocarp seeds in the three mast fruiting events. Although the biology of insects preying on dipterocarp seeds during mast fruiting periods has gradually become clear, their biology during periods other than mast fruiting periods is still unrevealed. Finally, we will show our future research plans on seed-eating insects on various plant species during non-mast fruiting events.