Australia\u2019s bogong moths are guided by the stars as they navigate up to 1,000km to a place they\u2019ve never been before, new research has concluded, making them the first invertebrates confirmed to use celestial navigation.<\/p>\n
Each year in spring, bogong moths emerge from their breeding grounds in the country\u2019s south-east and migrate to the mountainous caves and rocky crevices of the Australian Alps to escape the summer heat.<\/p>\n
In autumn, they return to their breeding grounds to reproduce and die.<\/p>\n
But how do the moths know what direction to fly? And how do they know when they\u2019ve arrived at their destination?<\/p>\n
These questions have for decades bugged Prof Eric Warrant, who researches nocturnal vision in insects at Lund University.<\/p>\n
\u201cNobody\u2019s shown them [the way], their parents have been dead for three months,\u201d he said.<\/p>\n
\u201cHow the heck do they find this specific place that they\u2019ve never been to before?\u201d<\/p>\n
A bogong moth in the flight simulator during the research. Photograph: Eric Warrant<\/p>\n
Scientists in the 60s and 70s had already established that nocturnal migratory birds relied on stars and the Earth\u2019s magnetic field as compasses. They suspected bogong moths might do something similar.<\/p>\n
So, about 15 years ago, Warrant \u2013 along with an international team of researchers \u2013 set about trying to find out.<\/p>\n
On land in the Snowy Mountains, researchers built a flight simulator for moths \u2013 roughly 50cm wide and lined with black felt \u2013 where the night sky was projected above them like a small planetarium.<\/p>\n
Moths \u2013 captured mid-migration \u2013 were gently tethered at the centre, where they continued to \u201cfly like mad\u201d, Warrant said, but still manoeuvre and change direction.<\/p>\n
Earlier research<\/a> had revealed the Earth\u2019s magnetic field played a role in steering flight, so a device called a Helmholz coil was used to cancel out magnetic fields, leaving only visual cues \u2013 the stars \u2013 to navigate by.<\/p>\n In experiments, conducted across two springs and two autumns, researchers manipulated the direction of the night sky \u2013 recreating it realistically, then turning it 180 degrees.<\/p>\n Consistently, the moths adjusted their bearings in order to fly in seasonally appropriate directions based on the stars, even when the sky was rotated.<\/p>\n When the stars were scrambled \u2013 without the Milky Way or the constellations \u2013 the moths became completely disoriented, Warrant said. They kept on flying, but went in all sorts of directions.<\/p>\n In a separate experiment, researchers inserted an electrode into the moth\u2019s brain, and recorded neurological responses as they rotated the sky.<\/p>\n Brain regions dedicated to processing visual information and for navigation and steering fired strongly in response to these changes in orientation, particularly when moths were facing southwards.<\/p>\n skip past newsletter promotion<\/a><\/p>\n Sign up to Breaking News Australia<\/p>\n Get the most important news as it breaks<\/p>\n Privacy Notice: <\/strong>Newsletters may contain info about charities, online ads, and content funded by outside parties. For more information see our Privacy Policy<\/a>. We use Google reCaptcha to protect our website and the Google Privacy Policy<\/a> and Terms of Service<\/a> apply.<\/p>\n after newsletter promotion<\/p>\n \u2018Sophisticated little critters\u2019: bogong moths on a cave wall. Photograph: Eric Warrant<\/p>\n Their findings, published in Nature<\/a>, demonstrate that bogong moths rely on stellar cues, as well as the Earth\u2019s magnetic field, as compasses to guide their long-distance journey.<\/p>\n \u201cThis is a truly remarkable insect,\u201d Warrant said. \u201cIt can make this incredible journey with a tiny brain and a small nervous system, and do it in two directions.\u201d<\/p>\n \u201cPeople still think of insects as little automatons,\u201d said Dr Kate Umbers, an associate professor in zoology at Western Sydney University and the managing director of Invertebrates Australia.<\/p>\n \u201cThey\u2019re much more sophisticated little critters than we usually give them credit for.\u201d<\/p>\n Umbers, who was not involved in the study, said the findings provided \u201ca great weight of evidence\u201d towards bogong moths having directional flight during their migration, as opposed to being blown around by prevailing winds.<\/p>\n Bogong moth populations have plummeted in recent years, but fundamental knowledge gaps and uncertainties have prevented<\/a> the species from being listed under federal environment laws.<\/p>\n