Squirrel pollination ofMucuna macrocarpa(Fabaceae) in Taiwan

Abstract

Explosive opening is an important process for pollination of Mucuna flowers. It is generally triggered by an animal pollinator specific to each Mucuna species. Although Mucuna macrocarpa has been reported to be pollinated by a nectar-eating bat, the distributional ranges of this plant and that of the nectar-eating bats do not overlap completely. Previous research suggested that this plant could be pollinated by other species depending on the region. In Taiwan, where nectar-eating bats are absent, 2 species of squirrels (Callosciurus erythraeus and Tamiops maritimus) and masked palm civets (Paguma larvata) were recorded as explosive openers. Of these 3 species, C. erythraeus was the most frequent and successful visitor—it opened the flowers in the same manner as nectar-eating bats. The other 2 species successfully opened only a few flowers and were therefore less effective pollinators. However, these opened flowers were subsequently visited by several insects, suggesting that the actions of the mammalian pollinators might have contributed to pollen transfer. Our data indicate that explosive openers of M. macrocarpa are not highly specialized and vary among the regions depending on the local fauna. Hence, this species, characterized by the explosive opening mechanism, is pollinated by different mammal species and insects in different regions.