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

• Published in: Flora. Morphologie, Geobotanik, Oekophysiologie Geobotanik, Oekophysiologie, 2019-11, Vol.260, p.151467, Article 151467
• Main Authors: Pakum, Wittaya, Kongbangkerd, Anupan, Srimuang, Kanok-Orn, Gale, Stephan W., Watthana, Santi
• Format: Article
• Language: English
• Subjects: Breeding system; Pollination; Scuttle flies; Self-incompatibility
• ISSN: 0367-2530; 1618-0585
• DOI: 10.1016/j.flora.2019.151467

•A phorid fly is reported to be the pollinator of a Bulbopyllum species for the first time.•Sapromyiophily is inferred in Bulbophyllum nipondhii.•Bulbophyllum nipondhii is predominantly outcrossing and strongly self-incompatible.•Pollinator visits were infrequent, leading to low fruit set and probably contributing to rarity in the orchid. 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.