© 1991 by The Society for Integrative and Comparative Biology
Is Geomagnetic Sensitivity Real? Replication of the Walker-Bitterman Magnetic Conditioning Experiment in Honey Bees1
Division of Geological and Planetary Sciences, The California Institute of Technology Pasadena, California 91125
Although the presence of geomagnetic sensitivity has been suspected for a long time in a variety of marine and terrestrial animals, many responses reported in the literature have been based on extensive statistical analysis of orientation results or rely on obscure behavioral activities (like cetacean strandings or honey bee waggle dances.) None of these reports have yet approached the level of clarity and simplicity displayed in experiments with the magnetotactic bacteria, which is the best example of geomagnetic sensitivity in any living organism. Furthermore, claims of magnetic effects on living organisms pervade the literature of biomagnetism, but many have failed subsequent attempts at replication. We need to develop simple and easily replicated experiments for marine and terrestrial animals which can be modified to answer basic questions concerning the psychophysics of any geomagnetic sensory system which might be present. In this paper, we report the first replication of the Walker-Bitterman magnetic anomaly conditioning experiment in honey bees, as well as one of our attempts to slightly alter their basic protocol. We also report our attempts to condition honey bees to magnetic direction in simple maze experiments, and the initial results of a pulse-remagnetization experiment designed to test the ferromagnetic transduction hypothesis. We conclude honey bees are sensitive to the geomagnetic field, that the signal processing for it is more complex than previously thought, and that a ferromagnetic transducer is compatible with all known behavioral data.