Latest news with #southeasternAustralia
CNN
an hour ago
- Science
- CNN
Tiny brown moth navigates 600 miles using stars — just like humans and birds
(CNN) — Each year, a tiny species in Australia makes a grueling 620-mile (1,000-kilometer) nighttime migration, and it's pulling off the feat in a way only humans and migratory birds have been known to do, a new study has found. Bogong moths looking to escape the heat travel in the spring from all over southeastern Australia to cool caves in the Australian Alps, where they huddle in a dormant state. The insects then fly all the way back in the fall to mate and die. Researchers replicated the conditions of this astonishing journey in the lab and discovered a key tool the moths used to find their way: the starry night sky. 'It is an act of true navigation,' said Eric Warrant, head of the Division of Sensory Biology at Lund University in Sweden, and a coauthor of the study published Wednesday in the journal Nature. 'They're able to use the stars as a compass to find a specific geographic direction to navigate, and this is a first for invertebrates.' Stars are not the only navigational cue the insects use to reach their destination. They can also detect Earth's magnetic field, according to evidence found by previous research conducted by Warrant and some of his colleagues from the new study. By using two cues, the moths have a backup in case either system fails — for example, if there is a magnetic anomaly or the night sky is cloudy. 'With a very small brain, a very small nervous system, (the moths) are able to harness two relatively complex cues and not only detect them, but also use them to work out where to go,' Warrant added. 'And I think that just adds a piece to the growing consensus that the insects have quite remarkable abilities and are truly amazing creatures.' Native to Australia, the Bogong moth, or Agrotis infusa, is entirely nocturnal and has an adult wingspan of about 2 inches (5 centimeters). 'They're a very nondescript little brown moth, that people would not necessarily distinguish from any other little brown moth,' Warrant said. Even though the moths normally migrate in the billions, their numbers have crashed in recent years, and the species is now endangered and appears on the International Union for Conservation of Nature's Red List. After discovering about five years ago that the insects could sense Earth's magnetic field, Warrant said he suspected that they might also be using visual cues to support their navigation. To test the theory, Warrant — who is from Australia — set up a lab with his colleagues in his own house, about 93 miles (150 kilometers) north of the moths' final destination in the Australian Alps. 'We captured the moths using a light trap, we brought them back to the lab, and then we glued a very thin rod on their back, made out of tungsten, which is nonmagnetic. Once you've done that, you can hold that little rod between your fingers, and the moth will fly very vigorously on the end of that tether,' he said. The researchers then coupled that rod to another one, also made of tungsten but much longer, allowing each moth to fly in any direction while an optical sensor detected exactly where the insect was going, relative to north, every five seconds. The experiment was set up in an enclosed, cylindrical 'moth arena,' with an image of the southern night sky projected on the roof, replicating exactly what was outside the lab on the day and time of the experiment. 'What we found is that moth after moth flew in their inherited migratory direction,' Warrant said. 'In other words, the direction they should fly in order to reach the caves in spring, which is a southwards direction for the moths we caught, or northwards away from the caves in autumn, which is very interesting.' Crucially, the effect of Earth's magnetic field was removed from the arena, via a device called a Helmholtz coil, which created a 'magnetic vacuum' so that the moths could only use visual cues. 'The moths couldn't rely on the Earth's magnetic field to do this task,' Warrant said. 'They had to rely on the stars. And they did.' About 400 moths were captured for this behavioral experiment and safely released afterward. The researchers collected a smaller sample of about 50 moths to try to understand the neural mechanism they used to navigate, which involved sticking electrodes in the insects' brains and resulted in death. 'A little moth can't see many stars, because its eye has a pupil which is only about 1/10th of the width of our own pupil at night,' Warrant said. 'But it turns out, because of the optics of the eye, they're able to see that dim, nocturnal world about 15 times more brightly than we do, which is fantastic, because they would be able to see the Milky Way much more vividly.' Warrant said he believes the insects are using this enhanced brightness as a visual compass to keep heading in the right direction. Apart from birds and humans, only two other animals navigate in a similar way, but with crucial differences from the moths, according to Warrant. The North American monarch butterfly also migrates over long distances using a single star as a compass, but that star is the sun, as the insect only flies during daytime. And some dung beetles use the Milky Way to find their way at night, but for the much simpler task of going in a straight line over a short distance, which does not really compare with the moths' long journey to a highly specific destination. What makes the Bogong moth's skill even more extraordinary is that the insect only makes this trip once in its life, so its ability to navigate must be innate. 'Their parents have been dead for three months, so nobody's shown them where to go,' Warrant said. 'They just emerge from the soil in spring in some far-flung area of southeastern Australia, and they just simply know where to go. It's totally amazing.' Warrant and his colleagues have not only discovered an entirely new compass mechanism in a migrating insect, but they have opened up an exciting avenue of research, as there are still many questions remaining about how the moths detect and use the information from their star compass, according to Jason Chapman, an associate professor at the Centre for Ecology and Conservation of the UK's University of Exeter. Chapman was not involved in the new research. 'Many questions remain,' he added via email, 'such as how the Bogong moths detect the information, how they use it to determine the appropriate direction in which to fly through the course of the night and between seasons, how they integrate their star and magnetic compasses, and how widespread these mechanisms may (or may not) be among other migratory moths and other nocturnal insects.' The findings are really exciting and add to scientists' knowledge about the ways that insects travel vast distances across continents, said Jane Hill, a professor of ecology at the University of York in the UK, who also was not involved with the study. 'They are able to navigate in the appropriate direction even though the stars move each night across the sky,' she said. 'This feat of insect migration is even more amazing given that different generations make the journey each year and there are no moths from previous generations to show the way.
CNN
an hour ago
- Science
- CNN
Tiny brown moth navigates 600 miles using stars — just like humans and birds
(CNN) — Each year, a tiny species in Australia makes a grueling 620-mile (1,000-kilometer) nighttime migration, and it's pulling off the feat in a way only humans and migratory birds have been known to do, a new study has found. Bogong moths looking to escape the heat travel in the spring from all over southeastern Australia to cool caves in the Australian Alps, where they huddle in a dormant state. The insects then fly all the way back in the fall to mate and die. Researchers replicated the conditions of this astonishing journey in the lab and discovered a key tool the moths used to find their way: the starry night sky. 'It is an act of true navigation,' said Eric Warrant, head of the Division of Sensory Biology at Lund University in Sweden, and a coauthor of the study published Wednesday in the journal Nature. 'They're able to use the stars as a compass to find a specific geographic direction to navigate, and this is a first for invertebrates.' Stars are not the only navigational cue the insects use to reach their destination. They can also detect Earth's magnetic field, according to evidence found by previous research conducted by Warrant and some of his colleagues from the new study. By using two cues, the moths have a backup in case either system fails — for example, if there is a magnetic anomaly or the night sky is cloudy. 'With a very small brain, a very small nervous system, (the moths) are able to harness two relatively complex cues and not only detect them, but also use them to work out where to go,' Warrant added. 'And I think that just adds a piece to the growing consensus that the insects have quite remarkable abilities and are truly amazing creatures.' Native to Australia, the Bogong moth, or Agrotis infusa, is entirely nocturnal and has an adult wingspan of about 2 inches (5 centimeters). 'They're a very nondescript little brown moth, that people would not necessarily distinguish from any other little brown moth,' Warrant said. Even though the moths normally migrate in the billions, their numbers have crashed in recent years, and the species is now endangered and appears on the International Union for Conservation of Nature's Red List. After discovering about five years ago that the insects could sense Earth's magnetic field, Warrant said he suspected that they might also be using visual cues to support their navigation. To test the theory, Warrant — who is from Australia — set up a lab with his colleagues in his own house, about 93 miles (150 kilometers) north of the moths' final destination in the Australian Alps. 'We captured the moths using a light trap, we brought them back to the lab, and then we glued a very thin rod on their back, made out of tungsten, which is nonmagnetic. Once you've done that, you can hold that little rod between your fingers, and the moth will fly very vigorously on the end of that tether,' he said. The researchers then coupled that rod to another one, also made of tungsten but much longer, allowing each moth to fly in any direction while an optical sensor detected exactly where the insect was going, relative to north, every five seconds. The experiment was set up in an enclosed, cylindrical 'moth arena,' with an image of the southern night sky projected on the roof, replicating exactly what was outside the lab on the day and time of the experiment. 'What we found is that moth after moth flew in their inherited migratory direction,' Warrant said. 'In other words, the direction they should fly in order to reach the caves in spring, which is a southwards direction for the moths we caught, or northwards away from the caves in autumn, which is very interesting.' Crucially, the effect of Earth's magnetic field was removed from the arena, via a device called a Helmholtz coil, which created a 'magnetic vacuum' so that the moths could only use visual cues. 'The moths couldn't rely on the Earth's magnetic field to do this task,' Warrant said. 'They had to rely on the stars. And they did.' About 400 moths were captured for this behavioral experiment and safely released afterward. The researchers collected a smaller sample of about 50 moths to try to understand the neural mechanism they used to navigate, which involved sticking electrodes in the insects' brains and resulted in death. 'A little moth can't see many stars, because its eye has a pupil which is only about 1/10th of the width of our own pupil at night,' Warrant said. 'But it turns out, because of the optics of the eye, they're able to see that dim, nocturnal world about 15 times more brightly than we do, which is fantastic, because they would be able to see the Milky Way much more vividly.' Warrant said he believes the insects are using this enhanced brightness as a visual compass to keep heading in the right direction. Apart from birds and humans, only two other animals navigate in a similar way, but with crucial differences from the moths, according to Warrant. The North American monarch butterfly also migrates over long distances using a single star as a compass, but that star is the sun, as the insect only flies during daytime. And some dung beetles use the Milky Way to find their way at night, but for the much simpler task of going in a straight line over a short distance, which does not really compare with the moths' long journey to a highly specific destination. What makes the Bogong moth's skill even more extraordinary is that the insect only makes this trip once in its life, so its ability to navigate must be innate. 'Their parents have been dead for three months, so nobody's shown them where to go,' Warrant said. 'They just emerge from the soil in spring in some far-flung area of southeastern Australia, and they just simply know where to go. It's totally amazing.' Warrant and his colleagues have not only discovered an entirely new compass mechanism in a migrating insect, but they have opened up an exciting avenue of research, as there are still many questions remaining about how the moths detect and use the information from their star compass, according to Jason Chapman, an associate professor at the Centre for Ecology and Conservation of the UK's University of Exeter. Chapman was not involved in the new research. 'Many questions remain,' he added via email, 'such as how the Bogong moths detect the information, how they use it to determine the appropriate direction in which to fly through the course of the night and between seasons, how they integrate their star and magnetic compasses, and how widespread these mechanisms may (or may not) be among other migratory moths and other nocturnal insects.' The findings are really exciting and add to scientists' knowledge about the ways that insects travel vast distances across continents, said Jane Hill, a professor of ecology at the University of York in the UK, who also was not involved with the study. 'They are able to navigate in the appropriate direction even though the stars move each night across the sky,' she said. 'This feat of insect migration is even more amazing given that different generations make the journey each year and there are no moths from previous generations to show the way.
CNN
an hour ago
- Science
- CNN
Tiny brown moth navigates 600 miles using stars — just like humans and birds
(CNN) — Each year, a tiny species in Australia makes a grueling 620-mile (1,000-kilometer) nighttime migration, and it's pulling off the feat in a way only humans and migratory birds have been known to do, a new study has found. Bogong moths looking to escape the heat travel in the spring from all over southeastern Australia to cool caves in the Australian Alps, where they huddle in a dormant state. The insects then fly all the way back in the fall to mate and die. Researchers replicated the conditions of this astonishing journey in the lab and discovered a key tool the moths used to find their way: the starry night sky. 'It is an act of true navigation,' said Eric Warrant, head of the Division of Sensory Biology at Lund University in Sweden, and a coauthor of the study published Wednesday in the journal Nature. 'They're able to use the stars as a compass to find a specific geographic direction to navigate, and this is a first for invertebrates.' Stars are not the only navigational cue the insects use to reach their destination. They can also detect Earth's magnetic field, according to evidence found by previous research conducted by Warrant and some of his colleagues from the new study. By using two cues, the moths have a backup in case either system fails — for example, if there is a magnetic anomaly or the night sky is cloudy. 'With a very small brain, a very small nervous system, (the moths) are able to harness two relatively complex cues and not only detect them, but also use them to work out where to go,' Warrant added. 'And I think that just adds a piece to the growing consensus that the insects have quite remarkable abilities and are truly amazing creatures.' Native to Australia, the Bogong moth, or Agrotis infusa, is entirely nocturnal and has an adult wingspan of about 2 inches (5 centimeters). 'They're a very nondescript little brown moth, that people would not necessarily distinguish from any other little brown moth,' Warrant said. Even though the moths normally migrate in the billions, their numbers have crashed in recent years, and the species is now endangered and appears on the International Union for Conservation of Nature's Red List. After discovering about five years ago that the insects could sense Earth's magnetic field, Warrant said he suspected that they might also be using visual cues to support their navigation. To test the theory, Warrant — who is from Australia — set up a lab with his colleagues in his own house, about 93 miles (150 kilometers) north of the moths' final destination in the Australian Alps. 'We captured the moths using a light trap, we brought them back to the lab, and then we glued a very thin rod on their back, made out of tungsten, which is nonmagnetic. Once you've done that, you can hold that little rod between your fingers, and the moth will fly very vigorously on the end of that tether,' he said. The researchers then coupled that rod to another one, also made of tungsten but much longer, allowing each moth to fly in any direction while an optical sensor detected exactly where the insect was going, relative to north, every five seconds. The experiment was set up in an enclosed, cylindrical 'moth arena,' with an image of the southern night sky projected on the roof, replicating exactly what was outside the lab on the day and time of the experiment. 'What we found is that moth after moth flew in their inherited migratory direction,' Warrant said. 'In other words, the direction they should fly in order to reach the caves in spring, which is a southwards direction for the moths we caught, or northwards away from the caves in autumn, which is very interesting.' Crucially, the effect of Earth's magnetic field was removed from the arena, via a device called a Helmholtz coil, which created a 'magnetic vacuum' so that the moths could only use visual cues. 'The moths couldn't rely on the Earth's magnetic field to do this task,' Warrant said. 'They had to rely on the stars. And they did.' About 400 moths were captured for this behavioral experiment and safely released afterward. The researchers collected a smaller sample of about 50 moths to try to understand the neural mechanism they used to navigate, which involved sticking electrodes in the insects' brains and resulted in death. 'A little moth can't see many stars, because its eye has a pupil which is only about 1/10th of the width of our own pupil at night,' Warrant said. 'But it turns out, because of the optics of the eye, they're able to see that dim, nocturnal world about 15 times more brightly than we do, which is fantastic, because they would be able to see the Milky Way much more vividly.' Warrant said he believes the insects are using this enhanced brightness as a visual compass to keep heading in the right direction. Apart from birds and humans, only two other animals navigate in a similar way, but with crucial differences from the moths, according to Warrant. The North American monarch butterfly also migrates over long distances using a single star as a compass, but that star is the sun, as the insect only flies during daytime. And some dung beetles use the Milky Way to find their way at night, but for the much simpler task of going in a straight line over a short distance, which does not really compare with the moths' long journey to a highly specific destination. What makes the Bogong moth's skill even more extraordinary is that the insect only makes this trip once in its life, so its ability to navigate must be innate. 'Their parents have been dead for three months, so nobody's shown them where to go,' Warrant said. 'They just emerge from the soil in spring in some far-flung area of southeastern Australia, and they just simply know where to go. It's totally amazing.' Warrant and his colleagues have not only discovered an entirely new compass mechanism in a migrating insect, but they have opened up an exciting avenue of research, as there are still many questions remaining about how the moths detect and use the information from their star compass, according to Jason Chapman, an associate professor at the Centre for Ecology and Conservation of the UK's University of Exeter. Chapman was not involved in the new research. 'Many questions remain,' he added via email, 'such as how the Bogong moths detect the information, how they use it to determine the appropriate direction in which to fly through the course of the night and between seasons, how they integrate their star and magnetic compasses, and how widespread these mechanisms may (or may not) be among other migratory moths and other nocturnal insects.' The findings are really exciting and add to scientists' knowledge about the ways that insects travel vast distances across continents, said Jane Hill, a professor of ecology at the University of York in the UK, who also was not involved with the study. 'They are able to navigate in the appropriate direction even though the stars move each night across the sky,' she said. 'This feat of insect migration is even more amazing given that different generations make the journey each year and there are no moths from previous generations to show the way.
Yahoo
2 days ago
- Science
- Yahoo
This Australian moth may be the 1st insect ever discovered to use stars for long-distance navigation
When you buy through links on our articles, Future and its syndication partners may earn a commission. Stand outside one spring night in southeastern Australia and you may be able to witness one of the biggest insect migrations in the world, as billions of brown Bogong moths (Agrotis infusa) flit across the sky. Each year in the spring, the moths migrate around 620 miles (1,000 kilometers) north to the Australian Alps, where they can avoid the heat by hiding in cool caves until the fall, when they return to their breeding grounds. While migration is not uncommon in insects, the Bogong moth's migration has been of particular interest to experts — how does a moth travel to a place it's never visited before? Researchers believe they now have the answer: stellar navigation. This would make the Bogong moth the first insect to use the stars for long-distance navigation as it makes its extended migratory journey. Stellar navigation has a long history for both humans and animals, from ancient Polynesians to migratory birds. Given the stars' dominance in the night sky, it's not surprising for experts to think that other animals, like insects, may also use these twinkling lights for navigating. "We knew from a previous study that the moths can use the geomagnetic field to navigate, but they only seemed to be able to do so in combination with visual landmarks, so we were thinking about what kind of landmarks these could be," explained Andrea Adden, a researcher at the Francis Crick Institute in the United Kingdom. "If you go to the Australian bush, where these moths live, and look around you at night, one of the most obvious visual landmarks is the Milky Way, which is always visible to some extent, independent of time of night and season," Adden said. "We know that daytime migratory insects use the sun, so testing the starry sky seemed an obvious thing to try." To test whether these moths are truly using the stars to navigate, the researchers captured several using a light-trap. This required the team to traverse into the dark, cold caves where the moths were resting during their migration, which, for some of the team, proved to be too challenging. According to Eric Warrant, a researcher at the University of Lund in Sweden and the leader of the project, "One of the most embarrassing [stories] was when Lena Nordlund from Swedish Radio (who was with us in Australia doing a documentary) asked why I always sent [the] youngsters in the cave and I always sat outside. I was forced to admit I was claustrophobic and was scared of going in — something that of course she included in the documentary." Though Warrant was not comfortable going into the caves, that didn't stop his collaborator, David Dreyer, also a researcher at the University of Lund, from challenging Warrant to a little competition to see who could catch the first Bogong moth of the migratory season. This competition lasted over a decade, with 20 different seasonal opportunities to compete. "[I] dominated this competition, [winning] 19 migratory seasons," Dreyer explained jokingly. "[My] 19 wins would remain unreported, until now. Justice at last." After capturing the moths, the team then placed them in a planetarium-like flight simulator, which included multiple projectors that could be programmed to give specific scenery. The simulator also blocked Earth's magnetic field, forcing the moths to try to navigate in the simulation by their eyesight alone. The researchers also attached electronic sensors to the moths to measure their brain activity. As Bogong moth brains are around the size of a grain of rice, adding the sensors was incredibly time-consuming. "Studying the neural basis of how these moths navigate reveals new processing mechanisms in the insect brain," Adden noted. "Even though human brains and insect brains are obviously very different, it often turns out that the computational principles are remarkably similar, so perhaps we can even learn something from moths that, one day, helps reveal something about the human brain." Once the moths were prepared, the researchers waited for evening in the outback, and then began to test the moths by recording their virtual flight paths in the simulator. "We continued this process until we had used all the prepared moths," Dreyer said. "The following morning was dedicated to data analysis. This routine continued until every moth from the previous catch had been tested — after which we would head out to catch a new batch." While studying the Bogong moths, the COVID-19 pandemic hit Australia, forcing a lockdown. For Adden, this meant being stuck out in the field. "A colleague and I were just wrapping up the field season in early 2020 when Australia entered its first Covid-19 lockdown, and the two of us were locked down at the field station for about a month," she said. "This wasn't as bad as it might seem — with no other humans in sight, we spent our days analyzing data, watching local wildlife and learning to sew." Adden even took the time to practice her astrophotography skills, taking photos of the very night sky her research subjects leveraged to navigate. After years of analysis, the researchers found that the Bogong moths fly in the seasonally appropriate direction (north or south) depending on the stars in the night sky, suggesting that they do in fact use the stars to guide them. "The stars are a very consistent cue. Even though the starry sky rotates throughout the night, the brightest part of the Milky Way is always in the South of the Southern celestial hemisphere," said Adden. "That makes it a very stable compass cue that is reliable not just across nights and seasons, but across centuries." From the moth's brain activity, the team also saw responses specific to certain rotations of the night sky in the flight simulator, and determined that their brains were the most active when they were "flying" in the right direction of their migration. While the Bogong moth is not the only insect to use the stars for guidance, it is the first to do so for long-distance journeys, scientists said. 'A previous study established that dung beetles use the stars to guide short-distance movements, but the beetles only travel a short distance (maybe 5-20 meters) as opposed to flying 1,000 km during a migration,' Ken Lohmann, a researcher at the University of North Carolina, Chapel Hill who was not involved in the study, told Studying how animals like moths navigate is not only fascinating, but can also help ensure the moth populations remain at a healthy level. "The Bogong moth population declined dramatically after the recent drought and 2020 bushfires," explained Adden. "Understanding how their migration works, and which cues they use to navigate, may help us protect these insects, which in turn helps the entire alpine ecosystem of which the moths are an integral part — e.g., as food for pygmy possums and all sorts of birds during the summer months." Part of that conservation work is looking at the role urbanization and, more specifically, light pollution plays in affecting the moths' migratory path. "Light pollution may well be a problem for Bogong moths during their migration,' Adden said. 'On their way from Southern Queensland to the Australian Alps, they pass several major cities, such as Canberra, which can be disorienting and trap the moths. In fact, this happened several years ago, when a cloud of moths briefly took over the Australian Parliament." While the Bogong moth shows the ingenuity of animals, for researchers and conservationists alike, understanding the animal navigation process as a whole is key to understanding their lifestyle, and therefore being able to protect them further. "A central lesson of animal navigation is that species almost always have multiple ways to guide themselves," said Lohmann. This study was published online today (June 18) in the journal Nature.
Yahoo
2 days ago
- Science
- Yahoo
This Australian moth may be the 1st insect ever discovered to use stars for long-distance navigation
When you buy through links on our articles, Future and its syndication partners may earn a commission. Stand outside one spring night in southeastern Australia and you may be able to witness one of the biggest insect migrations in the world, as billions of brown Bogong moths (Agrotis infusa) flit across the sky. Each year in the spring, the moths migrate around 620 miles (1,000 kilometers) north to the Australian Alps, where they can avoid the heat by hiding in cool caves until the fall, when they return to their breeding grounds. While migration is not uncommon in insects, the Bogong moth's migration has been of particular interest to experts — how does a moth travel to a place it's never visited before? Researchers believe they now have the answer: stellar navigation. This would make the Bogong moth the first insect to use the stars for long-distance navigation as it makes its extended migratory journey. Stellar navigation has a long history for both humans and animals, from ancient Polynesians to migratory birds. Given the stars' dominance in the night sky, it's not surprising for experts to think that other animals, like insects, may also use these twinkling lights for navigating. "We knew from a previous study that the moths can use the geomagnetic field to navigate, but they only seemed to be able to do so in combination with visual landmarks, so we were thinking about what kind of landmarks these could be," explained Andrea Adden, a researcher at the Francis Crick Institute in the United Kingdom. "If you go to the Australian bush, where these moths live, and look around you at night, one of the most obvious visual landmarks is the Milky Way, which is always visible to some extent, independent of time of night and season," Adden said. "We know that daytime migratory insects use the sun, so testing the starry sky seemed an obvious thing to try." To test whether these moths are truly using the stars to navigate, the researchers captured several using a light-trap. This required the team to traverse into the dark, cold caves where the moths were resting during their migration, which, for some of the team, proved to be too challenging. According to Eric Warrant, a researcher at the University of Lund in Sweden and the leader of the project, "One of the most embarrassing [stories] was when Lena Nordlund from Swedish Radio (who was with us in Australia doing a documentary) asked why I always sent [the] youngsters in the cave and I always sat outside. I was forced to admit I was claustrophobic and was scared of going in — something that of course she included in the documentary." Though Warrant was not comfortable going into the caves, that didn't stop his collaborator, David Dreyer, also a researcher at the University of Lund, from challenging Warrant to a little competition to see who could catch the first Bogong moth of the migratory season. This competition lasted over a decade, with 20 different seasonal opportunities to compete. "[I] dominated this competition, [winning] 19 migratory seasons," Dreyer explained jokingly. "[My] 19 wins would remain unreported, until now. Justice at last." After capturing the moths, the team then placed them in a planetarium-like flight simulator, which included multiple projectors that could be programmed to give specific scenery. The simulator also blocked Earth's magnetic field, forcing the moths to try to navigate in the simulation by their eyesight alone. The researchers also attached electronic sensors to the moths to measure their brain activity. As Bogong moth brains are around the size of a grain of rice, adding the sensors was incredibly time-consuming. "Studying the neural basis of how these moths navigate reveals new processing mechanisms in the insect brain," Adden noted. "Even though human brains and insect brains are obviously very different, it often turns out that the computational principles are remarkably similar, so perhaps we can even learn something from moths that, one day, helps reveal something about the human brain." Once the moths were prepared, the researchers waited for evening in the outback, and then began to test the moths by recording their virtual flight paths in the simulator. "We continued this process until we had used all the prepared moths," Dreyer said. "The following morning was dedicated to data analysis. This routine continued until every moth from the previous catch had been tested — after which we would head out to catch a new batch." While studying the Bogong moths, the COVID-19 pandemic hit Australia, forcing a lockdown. For Adden, this meant being stuck out in the field. "A colleague and I were just wrapping up the field season in early 2020 when Australia entered its first Covid-19 lockdown, and the two of us were locked down at the field station for about a month," she said. "This wasn't as bad as it might seem — with no other humans in sight, we spent our days analyzing data, watching local wildlife and learning to sew." Adden even took the time to practice her astrophotography skills, taking photos of the very night sky her research subjects leveraged to navigate. After years of analysis, the researchers found that the Bogong moths fly in the seasonally appropriate direction (north or south) depending on the stars in the night sky, suggesting that they do in fact use the stars to guide them. "The stars are a very consistent cue. Even though the starry sky rotates throughout the night, the brightest part of the Milky Way is always in the South of the Southern celestial hemisphere," said Adden. "That makes it a very stable compass cue that is reliable not just across nights and seasons, but across centuries." From the moth's brain activity, the team also saw responses specific to certain rotations of the night sky in the flight simulator, and determined that their brains were the most active when they were "flying" in the right direction of their migration. While the Bogong moth is not the only insect to use the stars for guidance, it is the first to do so for long-distance journeys, scientists said. 'A previous study established that dung beetles use the stars to guide short-distance movements, but the beetles only travel a short distance (maybe 5-20 meters) as opposed to flying 1,000 km during a migration,' Ken Lohmann, a researcher at the University of North Carolina, Chapel Hill who was not involved in the study, told Studying how animals like moths navigate is not only fascinating, but can also help ensure the moth populations remain at a healthy level. "The Bogong moth population declined dramatically after the recent drought and 2020 bushfires," explained Adden. "Understanding how their migration works, and which cues they use to navigate, may help us protect these insects, which in turn helps the entire alpine ecosystem of which the moths are an integral part — e.g., as food for pygmy possums and all sorts of birds during the summer months." Part of that conservation work is looking at the role urbanization and, more specifically, light pollution plays in affecting the moths' migratory path. "Light pollution may well be a problem for Bogong moths during their migration,' Adden said. 'On their way from Southern Queensland to the Australian Alps, they pass several major cities, such as Canberra, which can be disorienting and trap the moths. In fact, this happened several years ago, when a cloud of moths briefly took over the Australian Parliament." While the Bogong moth shows the ingenuity of animals, for researchers and conservationists alike, understanding the animal navigation process as a whole is key to understanding their lifestyle, and therefore being able to protect them further. "A central lesson of animal navigation is that species almost always have multiple ways to guide themselves," said Lohmann. This study was published online today (June 18) in the journal Nature.
