Reproductive biology of a rare, fly-pollinated orchid, Bulbophyllum nipondhii Seidenf., in Thailand

Abstract

The breeding system and pollination biology of a rare epiphytic orchid, Bulbophyllum nipondhii Seidenf., were investigated in Northeast Thailand. We demonstrate that the species is strongly, but not completely, self-incompatible, with a fruit-set of 5.0–5.7% following manual selfing and 65.0–65.7% following manual out-crossing, and that it requires a pollen vector for effective pollination in the wild. Natural fruit-set was 4.2–6.7%. The flowers are nectarless and emanate a faint scent reminiscent of decaying wood. The elastically-hinged lip acts as a seesaw balance which tips when a pollinator enters the flower, propelling the insect against the column. Effective pollinators were an unidentified female scuttle fly species, Megaselia sp. (Diptera: Phoridae), with the flowers apparently conforming to a sapromyiophilous pollination syndrome. Phoridae are herewith reported as pollinators of Bulbophyllum for the first time.