Bogong moths use a stellar compass for long-distance navigation at night

Summary

Capture and care of mothsBogong moths (A. infusa) of both sexes were caught in the wild during their autumn and spring migrations (2019 and 2018) using a LepiLED insect light (www.gunnarbrehm.de), or a vertical beam search light (model GT175, Ammon Luminaire Company), placed in front of a white sheet suspended between two trees. Almost all of the animals were caught near the Mount Selwyn Snowfields (southeast New South Wales, Australia: 35.914° S, 148.444° E; elevation, 1,600 m), which is approximately 70 km north-northeast of the nearest aestivation cave in the Main Range of the New South Wales Alps. Thus, to reach these caves in spring, these moths (a tiny subset of all moths travelling to the mountains in a multitude of directions from across southeast Australia) would be expected to fly south-southwest in spring, and returning moths might be expected to travel north-northeast in autumn (which agrees with our behavioural results). A few animals were also caught near Thredbo (Dead Horse Gap, southeast New South Wales, Australia: 36.524° S, 148.260° E, elevation 1,580 m). These moths were used for electrophysiology only. Each captured moth was transferred to its own plastic container to isolate it from influence by other moths. After capture, moths were transported to the testing site Glenhare, a rural property near Adaminaby New South Wales (36.040° S, 148.864° E; elevation, 1,250 m), fed with 20% honey solution (in water) and stored in a cool and sheltered place (exposed to the natural light cycle) to recover from stress induced by capture.Laboratory for controlled indoor experimentsA purpose-built ferromagnetic-free laboratory located at Glenhare, Adaminaby (built on a concrete slab reinforced with fibreglass and constructed entirely from non-magnetic materials) housed the indoor behavioural and electrophysiological experiments (Extended Data Fig. 1c). Each experimental apparatus (behaviour and electrophysiology) has its own dedicated earth separated from the ma...