Vertebrate-Pollinated Plants

Abstract

Vertebrate pollination occurs exclusively among birds and mammals, with a few exceptions of fish and reptiles (Faegri and Pijl 1979). Pollination by birds is much more commonly found in the tropics, where several groups of birds are specialized to feed on floral nectar. The hummingbirds (Trochilidae) in the Neotropics have more than 374 species, sunbirds and spiderhunters (Nectarinidae) in the Paleotropics have 127 species, honeycreepers (Drepanididae) in Hawaii have 23 species (6 are now extinct), and honeyeaters (Meliphagidae) in Australia and New Guinea have 136 species. Members of these four families include 660 of a total of approximately 9000 bird species on Earth. Thus, bird-pollination prevails in the tropics. Pollinating mammals mainly include bats (Hopkins 1984; Cunningham 1995), but a few cases of non-flying mammals are known (Janson et al. 1981; Cathew and Goldingay 1997). The kinds of bats visiting flowers for nectar and pollen are limited in the tropics: long-tongued bats (Glossophaginae) in the Neotropics and fruit bats (Pteropodidae) in the Paleotropics. Other animals believed to act as pollinators are the marsupials of Australia (Carthew 1994), the primates in Madagascar and South America (Prance 1980; Garber 1988; Ferrari and Strier 1992; Overdorff 1992; Kress 1994), and rodents in Central America (Lumer 1980). Many flowers display special pollination syndromes—ornithophily and chi ropterophily—mainly in the tropics (Faegri and Pijl 1979). For example, 100 species out of approximately 600 angiosperms are estimated to be pollinated by hummingbirds in a montane forest in Costa Rica (Feinsinger 1983). In a lowland forest in Costa Rica, 39 subcanopy trees and shrubs out of 220 were pollinated by hummingbirds, 2 canopy tree species out of 52 were pollinated by hummingbirds, and 8 were pollinated by bats (Bawa 1990). Even in a warm temperate forest inYakushima Island, Japan, 3 species (Camellia japonica, Camellia sasanqua, Taxillus yadoriki) out of 36 woody plants were pollinated by the Japanese white eye (Zosterops japonica) (Yumoto 1987). But in the Asian tropics, very few studies have been carried out.