Floral Chemical Signatures in the GenusOphrysL.(Orchidaceae): A Preliminary Test of a New Tool for Taxonomy and Evolution

Ophrys flowers sexually swindle male insect pollinators that cross-pollinate flowers during acts of pseudocopulation on the labellum. Classification of this species-rich genus into a natural system is difficult, even with the present molecular methods, because of low interspecific genetic variability. We investigated the potential for flower chemical signatures generated from gas chromatography of Ophrys labellum extracts to distinguish taxa and indicate phylogenetic relationships. Labellum extracts of five taxa from southeast France belonging to the sections Araniferae and Pseudophrys were analyzed. We obtained a high variability among all individuals with a good discrimination among all species. We conclude that lipidic compounds on Ophrys labellum represent species-specific chemical signatures, as has proven useful in insect taxonomy. Furthermore, a possible population effect is detected for a poorly described, polytypical species. We conclude that chemical investigations should be continued to clarify the classification of closely related taxa and to better understand the evolutionary processes in this extraordinary genus.