Abstract: The lycosid spider, Pirata subpiraticus, is one of the major predators of rice planthoppers and other rice pests. Pitfall trapping indicated that a large number of these spiders move into rice fields from adjacent Zizania habitat after the transplantation of rice seedlings, most moving back to Zizania fields before the rice is harvested. Rubidium (Rb) mark-release tests indicated that the lycosid spiders could disperse up to 40 meters into rice field from a release site in a Zizania field, and suggest that Zizania fields are one of their refuges for overwintering. Direct marking of such predators with Rb is recommended as an effective tool for investigation of predator dispersal between habitats.

Key words: lycosid spider, rubidium marking, dispersal, rice, Zizania