Antennal movements as indicators of odor detection by worker honeybees

Detecting olfactory perception in animals is a difficult task requiring indirect investigation at the peripheral level ( e. g., using electroantennograms) or at the behavioral level ( e. g., using choice behavior assays). We show in restrained honeybees that variations in antennal movements can be used to analyze odor detection. Two methods, based on the analysis of digital recordings during odor stimulations, have been used: manual or automatic ( with image processing) data collection of the successive positions of the antennae. The results were similar for the two methods and showed that citral induced an increase in the velocity of the antennal movements. Comparing the olfactory stimulation ( citral) to air alone stimulation and to stimulation consisting of air saturated with water or quinine solution, we conclude from these observations that only volatile molecules induce detectable movements of the antennae in the honeybee.