- A recent study has put forward a faculty hitherto never observed in insects.
- Bogongs, Australian butterflies, are capable of finding themselves thanks to the stars.
- This work could make it possible to improve the protection of this threatened species.
Each year in the spring, the Australian sky is invaded by countless Bogongs butterflies. A very enduring night species, which does not hesitate to travel nearly 1,000 kilometers to flee the west of the country and avoid the strongest. The management of these insects? Caves located in the “Australian Alps”, in the southeast part of the island.
Scientists have so far ignored how these butterflies have managed to find their way. After identifying their ability to detect the terrestrial magnetic field using an internal compass, they revealed a new discovery in the review Nature
(new window). Through their study, researchers have shown that these night butterflies used the starry sky as a guide to go to the caves.
The first insects with such a faculty
“We discovered that a very, very small animal as a night butterfly, with a very small nervous system, a very small brain and very small eyes, is capable of interpreting the starry sky and finding a direction to fly”
said Eric Warrant, professor of zoology at the University of Lund, Sweden, one of the authors of the study.
In addition to humans, several species of birds have shown that they could use the stars to navigate large distances. NBCNews, which relays this work (new window)underlines that if we know that the Bousiers use the light of the stars to move over a few tens of meters, no insect had been documented as using stellar navigation to find their way in the night.
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It was by capturing wild night butterflies that the researchers discovered the exceptional navigation capacity of these butterflies. They suspended them from a thin tungsten rod inside a small “Flight simulator”
in the shape of a barrel. The back stuck to the rod, the animals could beat wings inside the simulator and turn as if they were stolen naturally. To objectify their results, scientists have also created a magnetic vacuum, so as to deactivate the internal magnetic compass of creatures and focus on their other senses. On the top of the flight simulator, an image of the night sky was projected, which can at any time be modified.
During the tests, the researchers adjusted the rotation of the sky and found that the night butterflies modified their flight patterns to compensate and define a new CAP. But when a random and fragmented sky model has been projected, the butterflies were lost. “The animals were completely disoriented”
observed David Dreyer, one of the other co -authors of the study. “For us, it was definitive proof that they used the stars for their navigation”.
In the process of disappearing, Bogong night butterflies were added in 2021 to the “Red List” of the International Union for Nature Conservation. According to scientists, recent discoveries could help stop the decline of the species, in particular via actions to reduce light pollution.
