Drs. Williams and Dressler at the University of Florida and their colleagues in Ecuador will study the interaction between Gongora orchid species and their native pollinators, bees of the euglossine group. The study will include analysis by gas- chromatography and mass-spectrometry of the chemistry of floral fragrances emitted by the orchids, which serve as attracting cues for pollinators. Field experiments in the tropics are designed to test whether orchid species produce diagnostic floral fragrances that attract only particular pollinating bees, or whether floral odors serve a "generalist" function, attracting many different pollinators. The results will be important in understanding the evolution of reproductive isolating barriers among orchid species and in determining the range of chemical cues that orient insect behaviors.
