DISCRIMINATION OF OILSEED RAPE VOLATILES BY HONEY-BEE - NOVEL COMBINED GAS-CHROMATOGRAPHIC ELECTROPHYSIOLOGICAL BEHAVIORAL ASSAY

A novel technique for the simultaneous monitoring of electroantennogra m (EAG) and conditioned proboscis extension (CPE) responses of honey b ees to the effluent from a gas chromatograph (GC) was developed to loc ate biologically active components in blends of plant volatiles and to investigate odor recognition at the peripheral and behavioral levels. A six-component mixture, comprising compounds previously identified a s oilseed rape floral volatiles, was used as the stimulus. Standard CP E and EAG recordings were done as a reference. EAG responses were elic ited from unconditioned bees by all the components presented either in the coupled or the standard mode. Conditioned bees gave larger EAG re sponses than unconditioned bees, suggesting that antennal sensitivity is enhanced by conditioning. At the behavioral level, in both the stan dard and the coupled modes, only conditioned bees showed the proboscis extension response, with the majority of individuals responding to li nalool, 2-phenylethanol, and benzyl alcohol.