Flowering phenology
Throughout the survey, flowering of 130 species (42 families) was recorded, including four exotic species (Hypochaeris radicata ,Taraxacum officinale , Trifolium repens , and Veronica persica ). Major families were Asteraceae (18 sp.), Rosaceae (16 sp.), Ranunculaceae (10 sp.), and Orchidaceae (8 sp.). Based on the records of flower visitors, 19 plant species (14.6%) were categorized as bee specialists, 11 species (8.5%) as bee generalists, 54 species (41.5%) as fly specialists, 18 species (13.8%) as fly generalists, and 28 species (21.5%) as mixture or unclear (Table S1).
In the early season (late May), 49 species (39% of all species excluding exotic plants) had set flowers. The number of flowering species was maximum in mid- to late July in which 80–88 species (70–71%) were flowering. Then, the number of flowering species decreased gradually, but 57 species (51%) were still flowering in early September. Flowering patterns were different between fly-visited species (fly specialists and generalists) and bee-visited species (bee specialists and generalists) (Fig. 2). Fly-visited plants showed a higher proportion of flowering species throughout the season (> 50%) with a peak in late July (72%), indicating a moderate seasonal change. In contrast, the flowering pattern of bee-visited plants showed a clear seasonality; only 21% of species were flowering in late May, but the number of flowering species increased rapidly with seasonal progress and attained a maximum level in mid-July (85%), then decreased gradually toward early September (58%).