Australian moths use the stars as a compass on 1000-km migrations

An intriguing discovery has been made about the migration patterns of the Australian bogong moth (Agrotis infusa), shedding light on its remarkable navigational abilities. These moths embark on an epic journey spanning over 1000 kilometers to seek refuge from the summer heat in cool caves nestled within the Australian Alps, making them the first known invertebrate to use the stars as a compass for long-distance navigation.

Each spring, billions of bogong moths begin their migration from different regions in southern Australia to the alpine caves after a period of feeding as caterpillars during the winter months. Once in the caves, they enter a phase of dormancy known as aestivation before returning to their breeding grounds.

Researchers have long been puzzled by how these moths navigate such vast distances to reach their high-altitude destination, especially considering the decline in their population in recent years. Previous studies have suggested that the moths rely on Earth’s electromagnetic field in conjunction with visible landmarks. However, a team of scientists led by Andrea Adden from the Francis Crick Institute in London sought to explore other potential cues guiding the moths’ migration.

By conducting experiments in which tethered moths were exposed to simulated night skies in a controlled laboratory setting, the researchers discovered that the bogong moths possess a unique ability to use the stars as a compass. When presented with accurate depictions of the night sky, the moths consistently oriented themselves in their migratory direction, demonstrating a reliance on celestial cues for navigation.

In a groundbreaking revelation, the team observed that when the starry sky image was rotated or altered, the moths’ flight direction correspondingly changed, indicating a direct correlation between the celestial orientation and their movement. Further analysis involving neural activity monitoring in the moths’ brains confirmed the role of stellar cues in guiding their migration.

While dung beetles have been known to utilize the Milky Way for short-distance orientation, the bogong moth stands out as the first documented invertebrate capable of utilizing celestial navigation for long-distance migration to unfamiliar destinations. This remarkable feat places them in an exclusive category alongside humans and certain species of nocturnal migratory birds known for their celestial navigation abilities.

Notably, other insects like the monarch butterfly (Danaus plexippus) rely on the sun for navigation, adjusting their flight path based on the time of day. The bogong moth’s utilization of stellar navigation highlights the sophisticated capabilities of insects with relatively simple visual systems, showcasing their adaptability in navigating across various environmental cues, including the sun, moon, and stars, even in low light conditions.

These findings not only expand our understanding of insect navigation but also underscore the remarkable capabilities of creatures like the bogong moth in utilizing celestial cues for long-distance migration. With dwindling populations raising concerns about their conservation, further research into the unique navigational strategies of these fascinating insects could provide valuable insights for their protection and preservation in the face of environmental challenges.

Cody Freas at Macquarie University in Sydney, Australia, emphasizes the significance of insects’ navigational prowess, particularly in low-light conditions. The bogong moth’s utilization of stellar navigation serves as a testament to the intricate mechanisms at play in their relatively simple visual systems, showcasing their ability to navigate across diverse environmental cues with precision and accuracy.