Behavioral differences of queens of the obligately monogynous and facultatively polygynous forms ofCamponotus nawai complex were examined. Queens of the monogynous form were groomed by and received food from workers more frequently but they walked about inside nests less frequently than queens of the polygynous form. Hierarchical relationships were not observed among queens of polygynous nests. In general, those queens were equally cared for by workers, aggregated around the center of nests, and showed no hostility toward each other.