Integrating floral scent, pollination ecology and population genetics

Floral scent is a key factor in the attraction of pollinators. Despite this, the role of floral scent in angiosperm speciation and evolution remains poorly understood. Modern population genetic approaches when combined with pollination ecology can open new opportunities for studying the evolutionary role of floral scent. 2. A framework of six hypotheses for the application of population genetic tools to questions about the evolutionary role of floral scent is presented. When floral volatile chemistry is linked to pollinator attraction we can analyse questions such as: Does floral volatile composition reflect plant species boundaries? Can floral scent facilitate or suppress hybridization between taxa? Can the attraction of different pollinators influence plant mating systems and pollen-mediated gene flow? How is population genetic structure indirectly influenced by floral scent variation? 3. The application of molecular tools in sexually deceptive orchids has confirmed that volatile composition reflects species boundaries, revealed the role of shared floral odour in enabling hybridization, confirmed that the sexual attraction mediated by floral odour has implications for pollen flow and population genetic structure and provided examples of pollinator-mediated selection on floral scent variation. Interdisciplinary studies to explore links between floral volatile variation, ecology and population genetics are rare in other plant groups. 4. Ideal study systems for future floral scent research that incorporate population genetics will include closely related taxa that are morphologically similar, sympatric and co-flowering as well as groups that display wide variation in pollination mechanisms and floral volatiles.