Form-specific fragances from Ophrys insectifera L. (Orchidaceae) attract species of different pollinator genera. Evidence of sympatric speciation?

Abstract

Two closely related forms of Ophrys insectifera were observed in the field to attract different pollinator species selectively. O. i. ssp. insectifera attracted males of two species of Argogorytes (Sphecidae, Hymenoptera Aculeata) and O. i. ssp. aymoninii attracted Andrena combinata males (Andrenidae, Apoidea, Hymenoptera Aculeata). A third form, O. aff. i. ssp. insectifera, attracted none of these three species. Volatile compounds from flowers and inflorescences of the three forms (originating from Öland, Sweden, and Aveyron, France) were collected, using entrainment, enfleurage, and solvent extraction techniques, and identified by gas chromatography - mass spectrometry. Scent differences between the three forms were confirmed in the amounts of aliphatic hydrocarbons (C11-C19), methyl esters (C14-C18), short chain aliphatic 1-alcohols (C6-C12), and monoterpene alcohols (C10). © 1993 Birkhäuser Verlag.