Get Regular Updates!
Search

Earth

image|

Ajay Narendra

The amazing Australian magnetic moths

The amazing Australian magnetic moths

Each year, billions of bogong moths travel over 1000km, probably to escape the heat. Now scientists know how they do it.

The amazing Australian magnetic moths

Talk about having magnetic personalities—a recent study found that an Australian moth is capable of using Earth’s magnetic fields to navigate across the country.

So far, such ability has only been known in birds, sea turtles and fish, so this is a first for the insect world.

The feat is accomplished by the bogong moth—a species found in parts of Queensland, New South Wales, Victoria and Western Australia.

The peculiar migratory habits of this species have long been known by locals. In ancient times, different Aboriginal tribes converged near the caves where these moths rested to feast on them.

Now, scientists are putting together the final pieces of the puzzle in understanding the migration of this iconic Australian species.

The bogong circle of life

Each spring when the temperature starts to rise, billions of bogong moths travel from southeastern Australia for more than 1000km across the country towards the Australian Alps. Here, they gather inside a group of alpine caves to escape the coming heat. In these caves, they find a comfy spot and go dormant throughout the summer.

View Larger
Image|Eric Warrant
Bogong moths travel more than 1000km across the country towards alpine caves to escape the summer heat.

When autumn arrives, they return to their birthplace to reproduce and die. The eggs will hatch into caterpillars, which remain underground throughout winter and eventually become moths. Then the cycle starts all over again.

What’s truly amazing is that, year after year, these moths find their way to the same caves and back to their place of birth.

“There are many migratory moth species, but the beauty of the bogongs is that we know exactly where they are going—the Snowy Mountains,” says David Dreyer, a research fellow at the Warrant lab in Lund, Sweden.

The incredible journey of the Bogong moth

How they find their way to the Snowy Mountains has always been a bit of a mystery. Until now.

Unravelling the mystery

The international team, which included Swedish and Australian researchers, tested how these moths behaved when faced with visual landmarks and magnetic fields. For their experiment, they used a custom-made outdoor flight simulator, built using ferromagnetic-free materials like wood and plastic. This was no easy task, David recalls.

“The biggest hassle was that we could not buy off-the-shelf gear, since all the little bits and pieces needed to be absolutely ferromagnetic free, so we had to have them machined by a workshop. On top of that, we did most of the experiments on a hilltop in NSW—this means strong winds, rain, changes in humidity and temperature—none of which constitute ideal experimental conditions,” David says.

For their experiment, the researchers used a custom-made outdoor flight simulator…
. Credit: David Dreyer
View Larger
Image |

David Dreyer

For their experiment, the researchers used a custom-made outdoor flight simulator…
…the biggest hassle was that it had to be absolutely ferromagnetic free
. Credit: Eric Warrant
View Larger
Image |

Eric Warrant

…the biggest hassle was that it had to be absolutely ferromagnetic free

This personalised setup ensured that there were no magnetic signals coming from the materials used so that whatever behaviour the moths showed was influenced only by the cues used by the researchers.

With this setup ready, a moth was placed inside the flight simulator while researchers tweaked with visual cues and magnetic fields. The moths actually make no headway inside this simulator, but they think they’re flying while being attached to a stick, which is why they flap their wings. During the experiment, magnetic north and some visual landmarks were placed on specific directions to see if it prompted the moths to try to fly towards them.

Image|Eric Warrant
The moths actually make no headway inside this simulator, but they think they’re flying, which is why they flap their wings

A moth compass

Researchers found that moths used both magnetic signals and visual landmarks to guide them. When the researchers tweaked magnetic and visual cues towards a specific direction, the moths responded by adjusting their flight path towards that direction. This showed that moths used both types of cues to navigate.

“When we tweaked with the magnetic field and the landmarks so that they gave conflicting signals, the moths were lost within minutes,” David says.

This means that the moths are relying on both magnetic fields and their eyes to find their way, but not all the time. Basically, they use these two cues to check they are heading in the right direction.

David says it’s a bit like finding your way hiking through a forest with the help of a compass.

“Imagine that the campground where you want to go is northeast of you. So you take out your compass and check the horizon for a dominant landmark, like a particularly high tree, a peak or a hilltop, and you start walking towards that because you know your campground is in that direction,” he says.

“You do this because it is inconvenient to walk around looking at your compass all the time. But, better safe than sorry, you take a gander at the compass once in a while. This is basically what the animals are doing,” he adds.

View Larger
Image|David Dreyer
The way moths navigate is a bit like how you’d find your way hiking with the help of a compass.

Now David and his boss Eric Warrant are trying to figure out the really big mystery behind these moths’ behaviour. How is it that they are doing this? So far, scientists haven’t been able to figure out the biological mechanism that allows the moths to detect magnetic fields.

David thinks the secret is in the cells, and his next step is to identify what cells are involved in the detection of magnetic fields. He will also check if these moths use any other means of direction, like the cues in the sky.

With a little more research, maybe we’ll find out what drives these animals like a moth to a magnet.

Vital science VIDEO

Republish

Creative Commons Logo

Republishing our content

We want our stories to be shared and seen by as many people as possible.

Therefore, unless it says otherwise, copyright on the stories on Particle belongs to Scitech and they are published under a Creative Commons Attribution-NoDerivatives 4.0 International License.

This allows you to republish our articles online or in print for free. You just need to credit us and link to us, and you can’t edit our material or sell it separately.

Using the ‘republish’ button on our website is the easiest way to meet our guidelines.

Guidelines

You cannot edit the article.

When republishing, you have to credit our authors, ideally in the byline. You have to credit Particle with a link back to the original publication on Particle.

If you’re republishing online, you must use our pageview counter, link to us and include links from our story. Our page view counter is a small pixel-ping (invisible to the eye) that allows us to know when our content is republished. It’s a condition of our guidelines that you include our counter. If you use the ‘republish’ then you’ll capture our page counter.

If you’re republishing in print, please email us to let us so we know about it (we get very proud to see our work republished) and you must include the Particle logo next to the credits. Download logo here.

If you wish to republish all our stories, please contact us directly to discuss this opportunity.

Images

Most of the images used on Particle are copyright of the photographer who made them.

It is your responsibility to confirm that you’re licensed to republish images in our articles.

Video

All Particle videos can be accessed through YouTube under the Standard YouTube Licence.

The Standard YouTube licence

  1. This licence is ‘All Rights Reserved’, granting provisions for YouTube to display the content, and YouTube’s visitors to stream the content. This means that the content may be streamed from YouTube but specifically forbids downloading, adaptation, and redistribution, except where otherwise licensed. When uploading your content to YouTube it will automatically use the Standard YouTube licence. You can check this by clicking on Advanced Settings and looking at the dropdown box ‘License and rights ownership’.
  2. When a user is uploading a video he has license options that he can choose from. The first option is “standard YouTube License” which means that you grant the broadcasting rights to YouTube. This essentially means that your video can only be accessed from YouTube for watching purpose and cannot be reproduced or distributed in any other form without your consent.

Contact

For more information about using our content, email us: particle@scitech.org.au

Copy this HTML into your CMS
Press Ctrl+C to copy

We've got chemistry. Want something physical?