Butterfly wings under a microscope

April 27, 2017

The Hairstreak butterfly is found in Mexico

The Hairstreak butterfly is found in Mexico

Nature’s intricate mechanism for forming the nanostructures that help a butterfly species to camouflage itself against common leaves, has been revealed by researchers.

In an international collaboration, Dr Gerd Schroeder-Turk from Murdoch University and Dr Bodo Wilts from the Adolphe Merkle Institute at the University of Fribourg in Switzerland, used high resolution microscopy to shed light on the nanostructures, which are known as gyroids.

Gyroids are labyrinth-like three-dimensional structures first described by NASA scientist Allan Schoen. Dr Schroeder-Turk said there were tiny crystals made up of billions of these repeating units on the underside of the wings of the Hairstreak butterfly, found in Mexico. These structures are responsible for the green colour of the wings, despite them not having any green pigment.

“While we have known for a decade that many green butterflies from across the globe exhibit this special structure, this small Mexican butterfly reveals how the insects actually produce the structure,” said Dr Schroeder-Turk, from Murdoch’s School of Engineering and Information Technology.

“While we can make similar individual structures in the lab, nature has managed to make these at large scales on the wings of butterflies. The repeat of these nanostructures is similar to the wavelength of visible light, which explains its peculiar optical property of producing a green colour without the pigment. The green colour is simply a property of the special nanostructure.”

Dr Schroeder-Turk said that it is not yet possible to watch how these complex structures develop because the microscopy technology does not yet allow for the observation of live specimens.

However, from the final structures they studied, they could infer the structures grew in a multistep process.

“We believe the structures form thanks to a membrane mould that develops while the butterfly is in the chrysalis,” said Dr Schroeder-Turk. “Chitin, a fluid biopolymer solution, is then cast into that mould and this solidifies in it.

“However, strangely, our research seems to indicate that the making of the mould and the casting of the chitin seems to happen at the same time in these butterflies.

“It’s an exceptional feat of evolutionary nano engineering.”

The researchers say their findings could inspire future nanotechnology applications and they hoped further research will head in that direction.

“With optics and photovoltaics, we have taken inspiration from nature in terms of what structures we can copy and adapt. But we seem to neglect that we can also learn from the mechanisms nature employs to make these structures,” added Dr Schroeder-Turk.

“Efficiencies and innovations are sure to be revealed if we can unpick these processes.”

The research team also comprised scientists from the Friedrich-Alexander University (FAU) in Germany and Carl Zeiss X-ray Microscopy in the United States. Tomographic imaging was carried out by the Institute of Micro- and Nanostructure Research and the Center for Nanoanalysis and Electron Microscopy, both FAU, led by Professor Erdmann Spiecker and by Carl Zeiss X-ray Microscopy.

Their paper Butterfly gyroid nanostructures as a time-frozen glimpse of intracellular membrane development, has been published in Science Advances.

All the latest news from Murdoch University can be read here.


Print This Post Print This Post

Leave a comment

You can use these tags : <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>

We read every comment and will make every effort to approve each new comment within one working day. To ensure speedy posting, please keep your comments relevant to the topic of discussion, free of inappropriate language and in-line with the editorial integrity of this newsroom. If not, your comments may not be published.

Thanks for commenting!