Magnetoreception in migratory insects: the magnetic compass and the magnetic map in European migratory Lepidoptera

Studies demonstrated that animals can perceive the Earth's magnetic field (EMF) and use it for migration and navigation. Yet, the magnetic sense's underlying mechanism remains poorly understood. Although there exists evidence indirectly supporting several potential mechanisms, the primary magnetosensory cells (magnetoreceptors), their ultracellular structure, perceptive principle, and functional characteristics remain elusive. Birds are the most studied models in the area but they are difficult for finding magnetoreceptors due to high maintenance costs, the complexity of sourcing large samples, doing genetic editing and invasive interventions. Simpler migratory organisms, e.g., insects, might be good models due to their less complicated central nervous system, an opportunity to breed in a laboratory, create knockout animals and perform behavioural experiments in small setups. The ability to use magnetic sense for finding direction has been recently shown in North American and Australian migratory Lepidoptera (butterflies and moths) but never in European species. It also remains unknown whether migratory Lepidoptera can use EMF for navigation (position finding). The project's aim: to better understand how European migratory butterflies use EMF for orientation and navigation. Objective 1: to examine whether Red Admiral (Vanessa atalanta), a diurnal migrant, possesses an ability to find migratory direction by EMF. Objective 2: to test whether Red Underwing (Catocala nupta), a nocturnal migratory moth, can use EMF for navigation. The project will be delivered through non-invasive behavioural experiments using migratory individuals of both species captured and tested at 2 established field sites in Europe (Austria and East Baltic). Behavioural responses to a changed magnetic field will be tested with Flight Simulator, a setup testing insect's migratory orientation of a tethered animals while it is exposed to controlled navigational cues (sun, stars and EMF).