ABSTRACT
Evidence that honeybees respond to magnetic fields comes from both orientation (Lindauer & Martin, 1968, 1972; Towne & Gould, 1985) and conditioning experiments (Walker & Bitterman, 1985; Walker et al. 1988a). Perhaps because suitable behavioural methods have not yet been developed, the effects obtained are not very large. They are, however, reliable enough to permit evaluation of the ferromagnetic transduction hypothesis (Ising, 1945; Lowenstam, 1962; Gould et al. 1978; Kirschvink & Walker, 1985), to which the discovery of large numbers of single-domain particles of magnetite in the anterodorsal abdominal region of honeybees lends credence (Gould et al. 1978), and which alone among the various transduction hypotheses that have been proposed (Kirschvink & Gould, 1981; Kirschvink & Walker, 1985; Yorke, 1981; Kalmijn, 1974; Jungerman & Rosenblum, 1980; Leask, 1977; Korall & Martin, 1987) predicts that discrimination can be abolished by magnets attached in the vicinity of those particles (Jungerman & Rosenblum, 1980; Kirschvink & Walker, 1985). Free-flying honeybees were trained in two experiments to discriminate a local anomaly in the ambient magnetic field. Animals carrying small pieces of magnetized steel wire glued to the anterodorsal abdomen failed in the task, but untreated animals and control animals carrying small pieces of nonmagnetic wire succeeded. The results imply that the magnetite crystals in the anterodorsal abdomen play a critical role in magnetoreception by honeybees.
