Foraging behavior observations
To estimate the types of floral visitors and their foraging behaviors (for pollen or/and nectar) inH. mutabilis , we (four observers) observed the foraging behaviors of various visitors in the periods from 08:30 to 17:30 on sunny days in October 2023. Four plots (2m × 2m) were randomly established, each including 10 flowers. These plots were observed daily for 30 min. A total of 128 observation sessions were conducted. Using a camera (Nikon D7000), we recorded the foraging behaviors of various visitors. Moreover, we recorded the number of visits and the number of flowers visited by various visitors per 30 min, after which we calculated the visitation rates of each visitor (visits per flower per 30 min) by dividing the total number of observed flowers by the number of flowers visited per 30 min. The main pollinators were determined by the number of visits and the foraging behaviors.