In search of magnetosensitivity and ferromagnetic particles in Rhodnius prolixus: behavioral studies and vibrating...

Magnetoreception is a sensory mechanism with wide phylogenetic distribution, which many organisms use for navigation and orientation. Radical pair reactions and the use of magnetic particles have been proposed as mechanisms for magnetosensitivity in terrestrial animals. Magnetosensitivity and the presence of a ferromagnetic material were tested in the hematophagous bug Rhodnius prolixus (Hemiptera: Reduviidae: Triatominae) vector of Chagas disease in Colombia and Venezuela. R. prolixus is well known in both countries for its active dispersal that allows flow of individuals from sylvatic to domestic environments. Behavioral experiments quantifying the number of body rotations and quadrant changes in a Petri dish were carried out, applying 1 mT artificial field in a constant direction for 45 min and rotated 180° every 5 min for 45 min. In addition, magnetite presence in the abdomens of Apis mellifera (positive control) and the bodies of R. prolixus was tested using a vibrating sample magnetometer (VSM). No differences in the number of body rotations and quadrant changes were found in R. prolixus with and without the presence of an artificial magnetic field. Results obtained with the VSM indicate presence of ferromagnetic material (hysteresis loop) in A. mellifera abdomens and absence of ferromagnetic material in R. prolixus bodies. Both VSM and behavioral results suggest that magnetosensitivity by a ferromagnetic hypothesis is not present in R. prolixus. Finally, our results indicate that the VSM magnetometer is a sensitive technique for detecting ferromagnetic material in insect tissues.