Magnetic material diversity in Brazilian ants: displacement behaviour and environmental adaptability

How geomagnetic field information is collected and processed by insects for orientation and navigation remains elusive. In social insects, magnetic particles are well accepted as magnetic sensors. Ants have the ability to home and hunt, and some migratory and nomadic species can migrate or move over long distances for which magnetoreception is an important mechanism. It was shown previously that ferromagnetic resonance (FMR) spectral parameters of one migratory and one nomadic ant could be distinguished from Brazilian Solenopsis ant species and that these parameters correlate to the local geomagnetic field. The present work focuses on genera engaged in long-distance group raids and emigration collected mainly in the Amazon rainforest. A diversity of specimens of the genus was individually measured by FMR. Cluster analysis of the occurrence of the FMR Low Field component, associated with large or aggregated nanoparticles, and their spectral angular dependence resulted in a phylogenetic dendrogram of the genera of ants, principally from the North Brazilian region. The magnetic material characteristics of ants of the Invertebrate Collection from the Museum Paraense Emilio Goeldi were tested looking for their relation to ant genera and the local geomagnetic field. The observed spectral differences of the magnetic particles suggest that they are related to their capacity for adaptation to their environment and/or to displacement behaviour.