A recent study published in Nature reveals that the Australian bogong moth (Agrotis infusa) uses the night sky to navigate during its annual migration of approximately 1,000 kilometers. This makes it the first known invertebrate species to use stars for orientation over such long distances.
Every spring, billions of nocturnal bogong moths escape the heat of southeastern Australia by migrating to cool caves in the Australian Alps. They stay there until autumn, then return to their original habitats to reproduce and die. Scientists have long speculated about the navigation methods of these moths, previously assuming they used the Earth's magnetic field and visual landmarks.
In the new study, moths were captured at the beginning of their migration and placed in a flight simulator that mimicked the night sky while blocking the magnetic field. When the night sky was displayed correctly, the moths flew in the right direction. When star patterns were disturbed, they became disoriented. Brain activity showed that specific orientations of the night sky triggered responses in the moths' brains.
Although it is still unclear which specific features of the night sky the moths use—such as the Milky Way or certain nebulae—this discovery highlights the advanced navigation skills of these small insects. This adds to a growing number of examples of animals using celestial cues for navigation, a phenomenon previously observed in birds and dung beetles.
It is remarkable that an animal with a brain volume smaller than a grain of rice is able to use the night sky for navigation, according to study author David Dreyer of Lund University in Sweden. These findings highlight the complexity and adaptability of the bogong moth and contribute to our understanding of the diverse navigation strategies in the animal world.