Effect of Magnetic Field on the Foraging Rhythm and Behavior of the Swarm-founding Paper Wasp Polybia paulista Ihering (Hymenoptera: Vespidae)

The geomagnetic field can be used by insects for navigation and orientation, through different magnetoreception mechanisms. Magnetic sensitivity is very well documented in honeybees, ants and termites, but few studies have examined this capability in social wasps. The present study analyzed the magnetic sensitivity of the paper wasp Polybia paulista. The wasps' behavior was analyzed in the normal geomagnetic field and in the presence of external magnetic fields generated by permanent magnets or by Helmholtz coils. The frequency of foraging flights was measured in both conditions, and the behavior of the individuals on the nest surface was also analyzed. The magnetic field from the permanent magnet produced an increase in the frequency of departing foraging flights, and also the wasps grouped together on the nest surface in front of the magnet. The electromagnetic field created by the Helmholtz coils also increased foraging flights, but individuals did not show grouping behavior. This Helmholtz electromagnetic field induced wasp workers to perform "learning flights". These results show for the first time that Polybia paulista wasps are sensitive to magnetic fields, including it in the list of animal models to study magnetoreception and magnetic sensitivity.