Related Experiment Videos
Pollination by sexual deception-it takes chemistry to work
Björn Bohman1, Gavin R Flematti2, Russell A Barrow3
1Research School of Chemistry, The Australian National University, Acton, ACT 2601, Australia; Research School of Biology, The Australian National University, Acton, ACT 2601, Australia; School of Chemistry and Biochemistry, The University of Western Australia, Crawley, WA 6009, Australia.
Abstract:
Semiochemicals are of paramount importance in sexually deceptive plants. These plants sexually lure specific male insects as pollinators by chemical and physical mimicry of the female of the pollinator. The strategy has evolved repeatedly in orchids, with a wide diversity of insect groups exploited. Chemical communication systems confirmed by field bioassays include: alkenes and alkanes in bee pollinated Ophrys species, keto-acid and hydroxy-acids in scoliid wasp pollinated O. speculum, and cyclohexanediones and pyrazines in thynnine wasp pollinated Chiloglottis and Drakaea orchids, respectively. In Ophrys, stearoyl-acyl carrier protein desaturase (SAD) enzymes have been confirmed to control species level variation in alkene double bond position. The production of cyclohexanediones in Chiloglottis unexpectedly depends on UVB light, a phenomenon unknown for other plant specialised metabolites. Potential biosynthetic pathways for other systems are explored, and alternative approaches to further accelerate chemical discovery in sexually deceptive plants are proposed.