SEMINAR: Bayliss Seminar Series

Orchids are well known for their extraordinary species diversity and specialised pollination systems. Several hundred species of orchids are pollinated by the sexual deceit of male bees or wasps through mimicry of insect pheromones. Investigations into the chemical communication between orchids and their pollinators have revealed diverse classes of chemicals to be involved, e.g. alkanes, alkenes, monoterpenes, cyclohexanediones, (methylthio)phenols and pyrazines.

Sexual deception is emerging as one of the most well characterised pollination systems. Yet, despite the large number of studies, relatively few cases have combined chemical investigations with behavioural bioassays to provide a direct link between specific chemicals and explicit biological function. More commonly, it is often assumed that electrophysiologically active compounds, or compounds known to be active in other pollination systems, are responsible for the pollinator attraction in new systems.

In this talk I will discuss the use of various experimental techniques that have helped us further our understanding of the chemistry of pollination. The importance of careful chemical analyses, and thorough field bioassays confirming the precise function of identified natural products will be highlighted. An update on our current knowledge of the chemical systems operating in Australian sexually deceptive orchids will be presented.