Nav: Home

Bogong moths first insect known to use magnetic sense in long-distance nocturnal migration

June 21, 2018

Each spring, millions of nocturnal Bogong moths hatch across breeding grounds throughout southeastern Australia before flying over 1,000 kilometers through the dark night to reach a limited number of high alpine caves in the Australian Alps. After a few months of summer dormancy in those cool mountain caves, the moths fly right back to the breeding grounds where they were born. Now, researchers reporting in Current Biology on June 21 have found that the moths, like migratory birds, depend on the Earth's magnetic field to guide them on their way.

The discovery offers the first reliable evidence that nocturnal insects can use the Earth's magnetic field to steer flight during migration, the researchers say.

"When we began this study, we were convinced that the Bogong moth would exclusively use celestial cues in the sky, such as the stars and the moon, for navigation during migration," says Eric Warrant of the University of Lund, Sweden. "This, it turned out, was not the case. We were very surprised when we discovered that these moths could sense the earth's magnetic field just like night-migratory birds--and probably for the same reason."

Bogong moths and monarch butterflies are the only known insects to migrate over such long distances, and along such a specific route, to a distinct and geographically restricted destination visited by thousands of previous generations. In the new study, Warrant, David Dreyer, and colleagues set out to explore how such a small animal, with its tiny brain and nervous system, could travel so precisely and so far, having never been to their destination before. How could the same individuals then find their way back again after months in the mountains?

The researchers tethered migrating moths in an outdoor flight simulator. They found that the moths' flight direction turned predictably when dominant visual landmarks and a natural Earth-strength magnetic field were turned together. When those two cues were turned in conflicting ways, the moths became disoriented within minutes. The findings led the researchers to conclude that Bogong moths rely on a magnetic sense.

The findings suggest that nocturnally migrating insects might use the Earth's magnetic field as a compass during migration just as nocturnally migrating birds do. The researchers suspect the moths use a magnetic compass to determine their migratory direction and then align this direction with a celestial or terrestrial landmark in the same or a similar direction, which they then use as a visual beacon.

"This is essentially the same strategy we use when hiking in wilderness terrain: we determine our direction with a compass and then look for some distant landmark in roughly the same direction--for instance a mountaintop or a distant tree--and then head for this as we walk," Dreyer said. "When this landmark is no longer reliable, we again check our direction with the compass and choose a new landmark to orient towards."

The researchers say they would now like to dissect in more detail how and which visual and magnetic cues the moths use and how they are integrated in the brain. Due to the moth's relatively simple nervous system, they also hope to learn how the insects detect magnetic information, something that hasn't yet been achieved in any animal.

"The discovery of the magnetic sensor is one of the Holy Grails of sensory physiology," Warrant says.
-end-
The researchers were supported by the US Air Force Office of Scientific Research, the Swedish Foundation for International Cooperation in Research and Higher Education, the Royal Physiographic Society of Lund, the Swedish Research Council, the Volkswagen Stiftung, and the Natural Sciences and Engineering Research Council of Canada.

Current Biology, Dreyer et al.: "The Earth's Magnetic Field and Visual Landmarks Steer Migratory Flight Behavior in the Nocturnal Australian Bogong Moth" https://www.cell.com/current-biology/fulltext/S0960-9822(18)30632-8

Current Biology (@CurrentBiology), published by Cell Press, is a bimonthly journal that features papers across all areas of biology. Current Biology strives to foster communication across fields of biology, both by publishing important findings of general interest and through highly accessible front matter for non-specialists. Visit: http://www.cell.com/current-biology. To receive Cell Press media alerts, contact press@cell.com.

Cell Press

Related Magnetic Field Articles:

Earth's last magnetic field reversal took far longer than once thought
Every several hundred thousand years or so, Earth's magnetic field dramatically shifts and reverses its polarity.
A new rare metals alloy can change shape in the magnetic field
Scientists developed multifunctional metal alloys that emit and absorb heat at the same time and change their size and volume under the influence of a magnetic field.
Physicists studied the influence of magnetic field on thin film structures
A team of scientists from Immanuel Kant Baltic Federal University together with their colleagues from Russia, Japan, and Australia studied the influence of inhomogeneity of magnetic field applied during the fabrication process of thin-film structures made from nickel-iron and iridium-manganese alloys, on their properties.
'Magnetic topological insulator' makes its own magnetic field
A team of U.S. and Korean physicists has found the first evidence of a two-dimensional material that can become a magnetic topological insulator even when it is not placed in a magnetic field.
Scientists develop a new way to remotely measure Earth's magnetic field
By zapping a layer of meteor residue in the atmosphere with ground-based lasers, scientists in the US, Canada and Europe get a new view of Earth's magnetic field.
Magnetic field milestone
Physicists from the Institute for Solid State Physics at the University of Tokyo have generated the strongest controllable magnetic field ever produced.
New world record magnetic field
Scientists at the University of Tokyo have recorded the largest magnetic field ever generated indoors -- a whopping 1,200 tesla, as measured in the standard units of magnetic field strength.
Researchers discover link between magnetic field strength and temperature
Researchers recently discovered that the strength of the magnetic field required to elicit a particular quantum mechanical process corresponds to the temperature of the material.
Astronomers observe the magnetic field of the remains of supernova 1987A
For the first time, astronomers have directly observed the magnetism in one of astronomy's most studied objects: the remains of Supernova 1987A (SN 1987A), a dying star that appeared in our skies over thirty years ago.
Watch: Insects also migrate using the Earth's magnetic field
A major international study led by researchers from Lund University in Sweden has proven for the first time that certain nocturnally migrating insects can explore and navigate using the Earth's magnetic field.
More Magnetic Field News and Magnetic Field Current Events

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Rethinking Anger
Anger is universal and complex: it can be quiet, festering, justified, vengeful, and destructive. This hour, TED speakers explore the many sides of anger, why we need it, and who's allowed to feel it. Guests include psychologists Ryan Martin and Russell Kolts, writer Soraya Chemaly, former talk radio host Lisa Fritsch, and business professor Dan Moshavi.
Now Playing: Science for the People

#538 Nobels and Astrophysics
This week we start with this year's physics Nobel Prize awarded to Jim Peebles, Michel Mayor, and Didier Queloz and finish with a discussion of the Nobel Prizes as a way to award and highlight important science. Are they still relevant? When science breakthroughs are built on the backs of hundreds -- and sometimes thousands -- of people's hard work, how do you pick just three to highlight? Join host Rachelle Saunders and astrophysicist, author, and science communicator Ethan Siegel for their chat about astrophysics and Nobel Prizes.