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.To assess the effects of tropical forest remnants on the assemblage of parasitoid wasps in the surrounding areas, we conducted insect samplings with Malaise traps along line transects that were set up in a type of ecotone between isolated reserved forest (forest remnant) and its surrounding acacia plantation at Sampadi Forest Reserve, Lundu, Sarawak in Borneo. We set up three line transects, and five plots for Malaise traps in each line transect so that the five plots could represent five different locations in the gradient along the ecotone. Preliminary results from a few analyses of the samples showed that the relatively species-rich assemblage of parasitoid wasps in the forest remnants enriched the diversity of parasitoid wasp assemblage in the surrounding areas, where the species-richness of the assemblage had originally been relatively low, probably via dispersal by some species of parasitoid wasps from the forest remnants to the surrounding areas. We discuss several issues related to the results, and present some future research plans to solve these issues.