First report on pollinating behavior of the small carpenter bee Ceratina ridleyi Cockerell (Hymenoptera, Apidae) in Globba leucantha var. bicolor Holttum (Zingiberaceae)

Abstract

Small carpenter bees of the genus Ceratina are widespread, but little-studied as pollinators despite their presence in various pollinator assemblages. This study documents the importance of Ceratina ridleyi as a pollinator of the small-flowered Malaysian ginger Globba leucantha var. bicolor. Species of Zingiberaceae are defined by peculiar floral morphologies (e.g staminodes and a single functional anther) but are rarely studied for their insect pollinators. Surprisingly, C. ridleyi was revealed as the single pollinator of Globba leucantha’s showy flowers even though the presence of Apis sp., Trigona sp., and Amegilla sp. were observed in the study site. This small carpenter bee collects both pollen and nectar from the ginger flower. Pollen grains were observed attached to its scopal hairs and hairs on the ventral thorax and ventral abdomen. The bee contacts the flower’s sole stigma only during foraging for pollen, where the stigma contacts pollen accumulated on hairs of the bee’s ventral thorax and ventral abdomen. This study represents the first pollination report of a Ceratina pollinating a species of Zingiberaceae, and only the second report of any Ceratina pollinating a flower with complex morphology.