Bees and flies are dominant pollinators in alpine ecosystems. However, social bees are completely lacking in New Zealand in which most alpine plants are pollinated by flies. In contrast to the clear seasonality of social bees, seasonal trend of fly availability is less clear. This may cause different flowering structure between NZ and other ecosystems with social bees. We aim to detect a selective force of pollinator fauna acting on flowering phenology at community scale. We measured flowering patterns and seasonal activity of pollinators in the NZ mountains over 3 years, and compared with Japanese alpine ecosystems. Species composition at flowering gradually exchanged over season with large flowering overlaps among species in the NZ communities. In contrast, species composition clearly exchanged with seasonal progress in the JP communities. The frequency of flies depended on ambient temperature but independent on seasonal progress in both regions, while social bees clearly increased with seasonal progress in JP. When JP communities was classified into bee- and fly-pollinated groups, the phenological structure of fly-pollinated plants showed similar patterns with the NZ communities. These results suggest that social bees are the important creator of phenological structure in plant communities.