The Cellular Localization of Particulate Iron

Abstract

There is considerable behavioral evidence which suggests that a number of diverse species of animals (homing pigeons, warblers, salmon, salamanders, honeybees) are able to detect weak earth-strength magnetic fields and that they may be able to use this information for orientation. While other navigational clues have been proposed, e.g., olfaction (see Papi, 1982), the data suggest that some animals can sense magnetic fields. The identity and character of the sensory system that is involved in this “new” sense, however, is unknown. The discovery of magnetotactic bacteria by Blakemore (1975) and his colleagues suggested that an iron oxide, specifically magnetite, could be involved in the sensory transduction process. The observation that magnetite is also found in the abdomen of the honeybee (Gould et al., 1978) and the head of the homing pigeon (Walcott et al., 1979) gave impetus to the notion that magnetite could be of general importance in magnetic field sensitivity. Thus, in principle, if one could localize magnetite in a cellular system that satisfied certain requirements for a sensory system, one might be able to localize the sensory system responsible for magnetic field detection.