Abstract
Honeybees can deposit numerous iron granules in the trophocytes of ventral abdomen. These iron granules contain superparamagnetic magnetites, which seem to be magnetoreceptors. In this study, we investigate the pathway of the signal transduction of magnetoreception in honeybees （Apis mellifera.）The fluctuation of iron granules in size affected by additional magnetic field was monitored by digital amplification technique of confocal microscopy. The release of calcium ions in trophocytes affected by additional magnetic field was measured by confocal microscopy. The results show that additional magnetic field can induce the size of iron granules to shrink at the paralleled direction to magnetic field and to enlarge at the vertical direction. In addition, additional magnetic field can increase the release of calcium ions, which can be inhibited by microtubule-inhibitors (colchicine and taxol.) Our preliminary results show that the fluctuation in the size of iron granules can induce the relaxing and tensing of microtubules to trigger the release of calcium ions.