The pollination biology of Bulbophyllum species from Peninsular Malaysia

Bulbophyllum is the largest genus within the orchid family with an estimated number of 2,200 to 2,400 species worldwide. In Peninsular Malaysia, 126 taxa of Bulbophyllum spp. were previously recorded. This account, however, has not been updated for the past two decades. An updated checklist of Bulbophyllum spp. have brought the total number of species found in Peninsular Malaysia to 159 taxa or an increment of about 20 per cent. In the course of updating the checklist of the Bubophyllum of Peninsular Malaysia, five new species namely B. concavilabium, B. leptoflorum, B. naviculiforme, B. novemfilum and B. pauzii were described while B. praetervisum was reported as a new record. Information on the pollination in the genus Bulbophyllum especially Peninsular Malaysian species is scarce. Therefore, direct observations of Bulbophyllum pollination events were carried out to collect data even if it was using ex-situ plants. As results from this study, 32 Bulbophyllum spp. were observed visited and/or pollinated by various insects (mainly flies) of which 17 observations were recorded for the first time. Photographic and video evidences accompany these pollination observations. In the past, Bulbophyllum flowers are generally regarded as unpleasant or foul smelling. From this study, the floral scents were categorized into five types of scent based on human perception, which are musty, fishy, fragrant, spicy and stinky. The chemical profiling of floral compounds using High-Performance Liquid Chromatography (HPLC) analysis together with the Principal Coordinates Analysis (PCoA) using the binary data from the HPLC results further supported the categorising of these five floral scent types. Cluster analysis performed using the Unweighted Pair Group Method with Arithmetic Mean (UPGMA) showed interspecific relationships between the sampled taxa based on floral compounds found in the Bulbophyllum spp. studied. In addition to that, Bulbophyllum floral traits were scored and analysed using Statistical Package for the Social Sciences (SPSS) to determine the correlation between floral morphology and scent; and between floral morphology and pollinators. From the results, a total of 19, 18 and 20 character traits were found to be associated to pollinator family, pollinator guilds and floral scent groups respectively. From the total traits, ten character traits for pollinator family, 12 traits for pollinator guilds and eight traits for floral scent groups were found to be more important based on the mean values of CDA analysis. Additional material(s) submitted with thesis.