We studied dynamics of the isolated population of Melamphaus faber, a seed feeding pyrrhocorid bug and Raxa nishidai, its specialist predator, in the Bogor Botanic Gardens, West Java, Indonesia over 9 years intermittently from 1990 to 1998. Throughout the entire census periods, reproduction was always observed. The density of M. faber was fairly stable among years, which was closely synchronized with the annual changes in the food availability but not with those in the predation level. These results suggest that availability of the food resource exclusively determines the population dynamics of M. faber. Although the number of fruits largely fluctuated year to year, the number of the fruits accumulated on the ground, the actual food resource level, was fairly constant, which may contribute to the stable population dynamics of M. faber. The density of R. nishidai was extremely low but persistent over the years in spite of the fact that the population was completely isolated from adjacent populations.