VIBRATION TRANSMISSION CHARACTERISTICS OF THE LEGS OF FREELY STANDINGHONEYBEES

The leg vibrations of honeybees standing on a vibrating substrate were measured with laser Doppler vibrometry, both in freely standing bees and in bees attached to a holder. In both cases, no resonances were fo und. In the fixed bee preparation, the legs moved with approximately t he same amplitude as the stimulator. This was also the case in freely standing honeybees, except around 400 Hz, where an average attenuation of approximately 6 dB was observed. In the fixed bee preparation, the vertical movements of the legs were also measured during horizontal s timulation. The vertical vibration amplitude of the legs was 15-20 dB lower than the horizontal stimulation amplitude. The electrophysiologi cally and behaviourally determined thresholds for vibration stimulatio n increased by approximately 10 dB, when the stimulus direction was ch anged from vertical to horizontal. These observations support the noti on that the subgenual organ is sensitive mainly to vibrations in the d irection of the long axis of the leg.