Animal Cognition

A new study suggests that these Australian insects may be the first invertebrates to use the night sky as a compass during migration.In the summer, the walls of the caves in the Australian Alps are tiled with Bogong moths.Months before, billions of these small, nocturnal insects migrate about 600 miles to this destination — a place they have never visited before. Seeking refuge from the summer heat, they travel across southeast Australia to these cool alpine caves. Then, in the fall, they migrate back to their breeding grounds, where they eventually die.This remarkable journey has long puzzled scientists like Eric Warrant, a neurobiologist at Lund University in Sweden. “How on earth do these moths know where to go?” he said.Now, a study in the journal Nature by Dr. Warrant and his colleagues reveals the details of the insect’s impressive feat, showing that the Bogong moth may be the first invertebrate to use the starry night sky for migration. The findings suggest the insects use a set of internal compasses, one guided by the Earth’s magnetic field and the other by the night sky, to reach their destination.“That an insect brain that is smaller than a grain of rice is able to do this is just remarkable,” said Basil el Jundi, a neuroscientist at the University of Oldenburg in Germany who was not involved in the study.The Australian Bogong moth could fit in the palm of your hand. It has a two-inch-long wingspan, a small set of eyes and a brain that is roughly a tenth of the volume of a grain of rice. Despite their small size, they have played a big role in Australia. Once an important source of food for Indigenous Australians, the insect also holds a strong cultural value because of its impressive migration.Few insects undertake long-distance migration from dispersed breeding grounds to meet in a single, specific destination. The most famous example is the monarch butterfly, which relies on the sun as a visual compass. Like monarchs, Bogong moths use the Earth’s magnetic field for their long journey. They combine the magnetic compass with visual cues or markers, though researchers did not know what these were.We are having trouble retrieving the article content.Please enable JavaScript in your browser settings.Thank you for your patience while we verify access. If you are in Reader mode please exit and log into your Times account, or subscribe for all of The Times.Thank you for your patience while we verify access.Already a subscriber? Log in.Want all of The Times? Subscribe. More