title: Plant-pollinator interactions in tropical monsoon forests in Southeast Asia.
abstract: Forests with different flora and vegetation types harbor different assemblages of flower visitors, and plant-pollinator interactions vary among forests. In monsoon-dominated East and Southeast Asia, there is a characteristic gradient in climate along latitude, creating a broad spectrum of forest types with potentially diverse pollinator communities. To detect a geographical pattern of plant-pollinator interactions, we investigated flowering phenology and pollinator assemblages in the least-studied forest type, i.e., tropical monsoon forest, in the Vientiane plain in Laos. Throughout the 5-year study, we observed 171 plant species blooming and detected flower visitors on 145 species. Flowering occurred throughout the year, although the number of flowering plant species peaked at the end of dry season. The dominant canopy trees, including Dipterocarpaceae, bloomed annually, in contrast to the supra-annual general flowering that occurs in Southeast Asian tropical rain forests. Among the 134 native plant species, 68 were pollinated by hymenopterans and others by lepidopterans, beetles, flies, or diverse insects. Among the observed bees, Xylocopa, megachilids, and honeybees mainly contributed to the pollination of canopy trees, whereas long-tongued Amegilla bees pollinated diverse perennials with long corolla tubes. This is the first community-level study of plant-pollinator interactions in an Asian tropical monsoon forest ecosystem.
authors.affiliation: Graduate School of Human and Environmental Studies, Kyoto University, Yoshida-Nihonmatsu-cho, Sakyo-ku, Kyoto, 606-8501 Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Kato
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Kosaka
authors.forename: Atsushi
authors.initials: A
authors.lastname: Kawakita
authors.forename: Yudai
authors.initials: Y
authors.lastname: Okuyama
authors.forename: Chisato
authors.initials: C
authors.lastname: Kobayashi
authors.forename: Thavy
authors.initials: T
authors.lastname: Phimminith
authors.forename: Daovorn
authors.initials: D
authors.lastname: Thongphan