Pollination by nectar?foraging pompilid wasps: a new specialized pollination strategy for the Australian flora

The Pompilidae is a cosmopolitan and diverse group of wasps, which commonly feed on nectar. However, pollination systems specialized pompilids have not been documented in detail outside southern Africa. Here, we studied Caladenia drummondii (Orchidaceae) where, based floral traits preliminary field observations, predicted by sexual deception male pompilid wasps. Detailed pollinator observations were undertaken using baiting experiments at sites spanning 375 km. Following evidence for nectar some flowers C. drummondii, the sugar content labellum was analysed GC-MS. Floral spectral reflectance measured compared with other strategies. Males single species wasp (Calopompilus sp.) only visitors capable pollinating drummondii. Attempts to from surface frequent associated removal deposition pollinia. GC-MS analysis revealed larger quantities than reported species. While no or courtship behaviour observed, zig-zag circling flight approach flower suggestive odour-based attraction. similar sexually deceptive Caladenia. This study represents first confirmation system Although occurs during nectar-foraging, long-distance attraction cannot be ruled out as an explanation exclusive visitation. similarity indicates colour may impose constraint evolution pompilids.