Comparative magnetic measurements of migratory ant and its only termite prey

Abstract Termites and ants are social insects living organized in nests in castes. Behavioral studies with the migratory ant Pachycondyla marginata have shown that it conducts well-organized predatory raids toward nests of its only prey, the termite Neocapritermes opacus . The magnetic materials in these two insects were studied using a SQUID magnetometer for two orientations. The J r / J s and J r / χ 0 , ratios were calculated from the two insects hysteresis curves. These ratios are in the range of magnetite pseudo-single or multi-domain particle values. The magnetic material are distinguishable by H c values (30 Oe for ants and 100 Oe for termites) and by the magnetization magnitude, which is about two magnitude orders higher in the termite than in migratory ant. The Pachycondyla marginata SQUID results show an anisotropy in the magnetic material arrangement while for Neocapritermes opacus termite it is revealed by FMR spectra.