Modulation of spike frequencies by varying the ambient magnetic field and magnetite candidates in bees (Apis mellifera)

Abstract

1. Spontaneous activity was recorded from neurons in the second abdominal ganglion of bees. 2. Thirty per cent intensity modulations of the horizontal component of the background magnetic field provoked changes in the firing pattern of single neurons. 3. Two classes of neurons were distinguished and confirmed by statistical analysis. 4. Electron dense material in hairs and in or near the cutex may be single domain (SD) and superparamagnetic (SPM) magnetite. 5. A hypothesis is proposed for magnetoreception. Magnetite would act as an amplifier of the external magnetic induction changes. 6. The amplified magnetic field would influence neuronal elements only in restricted regions near the magnetite.