Electromagnetic field effects in Drosophila melanogaster

Many higher animals have evolved the ability to use the Earth’s magnetic field, particularly for orientation. However, the biophysical mechanism by which magnetoreception is achieved remains elusive. One theoretical model (the radical pair mechanism - RPM) proposes that the geomagnetic field is perceived by chemical reactions involving the blue-light photoreceptor Cryptochrome (CRY). Recent evidence supports the RPM in Drosophila melanogaster and reveals a mechanistic link with the circadian clock. Here I have confirmed, albeit with rather different results, that a low frequency electromagnetic field (AC-EMF) along with a Static Field (SF) exposure does affect circadian and activity behaviour in the fruit fly. Furthermore, I have developed two new assays to investigate the effects of EMF in Drosophila melanogaster, negative geotaxis and an additional light wavelength preference assay, revealing a net CRY-dependent response. My data support the idea of CRY mediated magnetoreception, thereby indirectly supporting the RPM. Furthermore, I provide some striking new results that challenge our view that only the canonical clock neurons contribute to behavioural rhythms in Drosophila melanogaster.