Identifying the Neuronal Basis for Magnetosensation and Orientation in Insects

Animals use a variety of sensory cues to navigate their environments as a survival mechanism to find food, avoid predators and migrate to places with more favorable environmental conditions. Different animals rely on different navigation strategies dependent on a combination of non-mutually exclusive sensory inputs including visual, olfactory, thermal and mechanical stimuli. The Earth’s magnetic field is a pervasive cue always present and varying predictably around the globe. The ability to sense the Earth’s magnetic field and use it as a compass cue for challenging orientation tasks during spectacular long-distance migrations has been documented in several behavioral studies in different species like birds, sea turtles and lobsters. As such, sensing the Earth’s magnetic field has been proposed as a potential source of positional information or nature’s own global positioning system. Incidentally, the vulnerability of satellite-based global positioning systems has prompted interest in the mechanisms underlying biological magneto-sensing. Numerous insect species undertake astonishing highly directed migrations over hundreds or thousands of kilometers to and from very specific geographical locations. Two prominent fascinating examples are the North American Monarch butterfly (Danaus plexippus) and the Australian Bogong moth (Agrotis infusa). Recent reports have evidenced the ability of these insects to sense the magnetic field and exploit it as a navigation cue. Several other non-migratory insects such as cockroaches, bees, ants and fruit flies have also been found to possess magneto-sensing capabilities. Probable mechanisms have been postulated to explain this ability, but despite years of research, the biological mechanism by which magnetic field information is sensed remains poorly understood and the location of the receptor cells responsible for this task has never been found. Addressing these questions is one of the greatest challenges of modern sensory biology. The experiments proposed in this project aim to identify specific brain regions and cell types involved in processing magnetic field stimuli in insects using the fruit fly (Drosophila melanogaster) as a model. We aim to use these results to trace neuronal signals associated with magnetic stimuli back to their input locations in the brain. The envisioned experiments have great potential to reveal the molecular identity and location of magnetoreceptor cells for the first time. The combined expertise of our interdisciplinary team will enable the development of a unique imaging platform that will open the door to study magnetosensing at the neural network level for the first time. This platform will be compatible with applications of other sensory modalities for comprehensive studies of brain function in the context of navigation. The discovery of the magnetoreceptor cells that is envisioned in this project will not only have implications for the fundamental understanding of the biophysical and biochemical mechanisms underlying magnetosensing but will also have much broader implications in applied fields like robotics, sensorics, health, ecology and agriculture.