Oriented magnetic material in head and antennae of Solenopsis interrupta ant

Ferromagnetic resonance (FMR) has been used to study the magnetic material in the antennae, head, thorax and abdomen of Solenopsis interrupta ants. The measurements were performed at room temperature (RT). The ferrimagnetic broad lines associated to magnetite/maghemite isolated nanoparticles (high field, HF) and to large nanoparticles or aggregates (low field, LF) in insect spectra are present in the S. interrupta body part spectra, although they slightly differ in resonant fields and lineshapes. The spectral absorption areas show (32±3)%, (24±2)%, (21±2)% and (23±1)% of magnetic material average fractions in antennae, head, abdomen and thorax, respectively. Only the resonance field of the head and antennae showed angular dependence. This work shows that head and antenna of S. interrupta ant present organized magnetic material, indicating a biomineralization process.