Tag Archives: Scripps Institution of Oceanography

Australian peacock spiders, photonic nanostructures, and making money

Researcher Bor-Kai Hsiung’s work has graced this blog before but the topic was tarantulas and their structural colour. This time, it’s all about Australian peacock spiders and their structural colour according to a December 22, 2017 news item on ScienceDaily,

Even if you are arachnophobic, you probably have seen pictures or videos of Australian peacock spiders (Maratus spp.). These tiny spiders are only 1-5 mm long but are famous for their flamboyant courtship displays featuring diverse and intricate body colorations, patterns, and movements.

The spiders extremely large anterior median eyes have excellent color vision and combine with their bright colors to make peacock spiders cute enough to cure most people of their arachnophobia. But these displays aren’t just pretty to look at, they also inspire new ways for humans to produce color in technology.

One species of peacock spider — the rainbow peacock spider (Maratus robinsoni) is particularly neat, because it showcases an intense rainbow iridescent signal in males’ courtship displays to the females. This is the first known instance in nature of males using an entire rainbow of colors to entice females. Dr. Bor-Kai Hsiung led an international team of researchers from the US (UAkron, Cal Tech, UC San Diego, UNL [University of Nebraska-Lincoln]), Belgium (Ghent University), Netherlands (UGroningen), and Australia to discover how rainbow peacock spiders produce this unique multi-color iridescent signal.

A December 22, 2017 Ghent University (Belgium) press release on Alpha Galileo, which originated the news item, provides more technical detail,

Using a diverse array of research techniques, including light and electron microscopy, hyperspectral imaging, imaging scatterometry, nano 3D printing and optical modeling, the team found the origin of this intense rainbow iridescence emerged from specialized abdominal scales of the spiders. These scales have an airfoil-like microscopic 3D contour with nanoscale diffraction grating structures on the surface.

The interaction between the surface nano-diffraction grating and the microscopic curvature of the scales enables separation and isolation of light into its component wavelengths at finer angles and smaller distances than are possible with current manmade engineering technologies.

Inspiration from these super iridescent scales can be used to overcome current limitations in spectral manipulation, and to further reduce the size of optical spectrometers for applications where fine-scale spectral resolution is required in a very small package, notably instruments on space missions, or wearable chemical detection systems. And it could have a wide array of implications to fields ranging from life sciences and biotechnologies to material sciences and engineering.

Here’s a video of an Australian rainbow peacock spider,

Here’s more from the YouTube description published on April 13, 2017 by Peacockspiderman,

Scenes of Maratus robinsoni, a spider Peter Robinson discovered and David Hill and I named it after him in 2012. You can read our description on pages 36-41 in Peckhamia 103.2, which can be downloaded from the Peckhamia website http://peckhamia.com/peckhamia_number…. This is one of the two smallest species of peacock spider (2.5 mm long) and the only spider we know of in which colour changes occur every time it moves, this video was created to document this. Music: ‘Be Still’ by Johannes Bornlöf licensed through my MCN ‘Brave Bison’ from ‘Epidemic Sound’ For licensing inquiries please contact Brave Bison licensing@bravebison.io

The University of California at San Diego also published a December 22, 2017 news release about this work, which covers some of the same ground while providing a few new tidbits of information,

Brightly colored Australian peacock spiders (Maratus spp.) captivate even the most arachnophobic viewers with their flamboyant courtship displays featuring diverse and intricate body colorations, patterns, and movements – all packed into miniature bodies measuring less than five millimeters in size for many species. However, these displays are not just pretty to look at. They also inspire new ways for humans to produce color in technology.

One species of peacock spider – the rainbow peacock spider (Maratus robinsoni) – is particularly impressive, because it showcases an intense rainbow iridescent signal in males’ courtship displays to females. This is the first known instance in nature of males using an entire rainbow of colors to entice females to mate. But how do males make their rainbows? A new study published in Nature Communications looked to answer that question.

Figuring out the answers was inherently interdisciplinary so Bor-Kai Hsiung, a postdoctoral scholar at Scripps Institution of Oceanography at the University of California San Diego, assembled an international team that included biologists, physicists and engineers. Starting while he was a Ph.D. student at The University of Akron under the mentorship of Todd Blackledge and Matthew Shawkey, the team included researchers from UA, Scripps Oceanography, California Institute of Technology, and University of Nebraska-Lincoln, the University of Ghent in Belgium, University of Groningen in Netherlands, and Australia to discover how rainbow peacock spiders produce this unique iridescent signal.

The team investigated the spider’s photonic structures using techniques that included light and electron microscopy, hyperspectral imaging, imaging scatterometry and optical modeling to generate hypotheses about how the spider’s scale generate such intense rainbows. The team then used cutting-edge nano 3D printing to fabricate different prototypes to test and validate their hypotheses. In the end, they found that the intense rainbow iridescence emerged from specialized abdominal scales on the spiders. These scales combine an airfoil-like microscopic 3D contour with nanoscale diffraction grating structures on the surface. It is the interaction between the surface nano-diffraction grating and the microscopic curvature of the scales that enables separation and isolation of light into its component wavelengths at finer angles and smaller distances than are possible with current engineering technologies.

“Who knew that such a small critter would create such an intense iridescence using extremely sophisticated mechanisms that will inspire optical engineers,” said Dimitri Deheyn, Hsuing’s advisor at Scripps Oceanography and a coauthor of the study.

For Hsiung, the finding wasn’t quite so unexpected.

“One of the main questions that I wanted to address in my Ph.D. dissertation was ‘how does nature modulate iridescence?’ From a biomimicry perspective, to fully understand and address a question, one has to take extremes from both ends into consideration. I purposefully chose to study these tiny spiders with intense iridescence after having investigated the non-iridescent blue tarantulas,” said Hsiung.

The mechanism behind these tiny rainbows may inspire new color technology, but would not have been discovered without research combining basic natural history with physics and engineering, the researchers said.

“Nanoscale 3D printing allowed us to experimentally validate our models, which was really exciting,” said Shawkey. “We hope that these techniques will become common in the future.”

“As an engineer, what I found fascinating about these spider structural colors is how these long evolved complex structures can still outperform human engineering,” said Radwanul Hasan Siddique, a postdoctoral scholar at Caltech and study coauthor. “Even with high-end fabrication techniques, we could not replicate the exact structures. I wonder how the spiders assemble these fancy structural patterns in the first place!”

Inspiration from these super iridescent spider scales can be used to overcome current limitations in spectral manipulation, and to reduce the size of optical spectrometers for applications where fine-scale spectral resolution is required in a very small package, notably instruments on space missions, or wearable chemical detection systems.

In the end, peacock spiders don’t just produce nature’s smallest rainbows.They could also have implications for a wide array of fields ranging from life sciences and biotechnologies to material sciences and engineering.

Before citing the paper and providing a link, here’s a story by Robert F. Service for Science magazine about attempts to capitalize on ‘spider technology’, in this case spider silk,

The hype over spider silk has been building since 1710. That was the year François Xavier Bon de Saint Hilaire, president of the Royal Society of Sciences in Montpellier, France, wrote to his colleagues, “You will be surpriz’d to hear, that Spiders make a Silk, as beautiful, strong and glossy, as common Silk.” Modern pitches boast that spider silk is five times stronger than steel yet more flexible than rubber. If it could be made into ropes, a macroscale web would be able to snare a jetliner.

The key word is “if.” Researchers first cloned a spider silk gene in 1990, in hopes of incorporating it into other organisms to produce the silk. (Spiders can’t be farmed like silkworms because they are territorial and cannibalistic.) Today, Escherichia coli bacteria, yeasts, plants, silkworms, and even goats have been genetically engineered to churn out spider silk proteins, though the proteins are often shorter and simpler than the spiders’ own. Companies have managed to spin those proteins into enough high-strength thread to produce a few prototype garments, including a running shoe by Adidas and a lightweight parka by The North Face. But so far, companies have struggled to mass produce these supersilks.

Some executives say that may finally be about to change. One Emeryville, California-based startup, Bolt Threads, says it has perfected growing spider silk proteins in yeast and is poised to turn out tons of spider silk thread per year. In Lansing, Michigan, Kraig Biocraft Laboratories says it needs only to finalize negotiations with silkworm farms in Vietnam to produce mass quantities of a combination spider/silkworm silk, which the U.S. Army is now testing for ballistics protection. …

I encourage you to read Service’s article in its entirety if the commercialization prospects for spider silk interest you as it includes gems such as this,

Spider silk proteins are already making their retail debut—but in cosmetics and medical devices, not high-strength fibers. AMSilk grows spider silk proteins in E. coli and dries the purified protein into powders or mixes it into gels, for use as additives for personal care products, such as moisture-retaining skin lotions. The silk proteins supposedly help the lotions form a very smooth, but breathable, layer over the skin. Römer says the company now sells tons of its purified silk protein ingredients every year.

Finally, here’s a citation for and a link to the paper about Australian peacock spiders and nanophotonics,

Rainbow peacock spiders inspire miniature super-iridescent optics by Bor-Kai Hsiung, Radwanul Hasan Siddique, Doekele G. Stavenga, Jürgen C. Otto, Michael C. Allen, Ying Liu, Yong-Feng Lu, Dimitri D. Deheyn, Matthew D. Shawkey, & Todd A. Blackledge. Nature Communications 8, Article number: 2278 (2017) doi:10.1038/s41467-017-02451-x Published online: 22 December 2017

This paper is open access.

As for Bor-Kai Hsiung’s other mentions here:

How tarantulas get blue (December 7, 2015 posting)

Noniridescent photonics inspired by tarantulas (October 19, 2016 posting)

More on the blue tarantula noniridescent photonics (December 28, 2016 posting)

How tarantulas get blue

Cobalt Blue Tarantula [downloaded from http://www.tarantulaguide.com/tarantula-pictures/cobalt-blue-tarantula-4/]

Cobalt Blue Tarantula [downloaded from http://www.tarantulaguide.com/tarantula-pictures/cobalt-blue-tarantula-4/]

That’s a stunning shade of blue on the tarantula and now scientists can explain why these and other ‘spiders’ are sometimes blue, from a Nov. 30, 2015 news item on ScienceDaily,

Scientists recently discovered that tiny, multilayer nanostructures inside a tarantula’s hair are responsible for its vibrant color. The science behind how these hair-raising spiders developed their blue hue may lead to new ways to improve computer or TV screens using biomimicry.

A Nov. 30, 2015 University of California at San Diego news release by Annie Reisewitz, which originated the news item, explains more,

Researchers from Scripps Institution of Oceanography at UC San Diego and University of Akron found that many species of tarantulas have independently evolved the ability to grow blue hair using nanostructures in their exoskeletons, rather than pigments. The study, published in the Nov. 27 issue of Science Advances, is the first to show that individual species evolved separately to make the same shade of a non-iridescent color, one that doesn’t change when viewed at different angles.

Since tarantulas’ blue color is not iridescent, the researchers suggest that the same process can be applied to make pigment replacements that never fade and help reduce glare on wide-angle viewing systems in phones, televisions, and other devices.

“There is strikingly little variety in the shade of blue produced by different species of tarantulas,” said Dimitri Deheyn, a Scripps Oceanography researcher studying marine and terrestrial biomimicry and coauthor of the study. “We see that different types of nanostructures evolved to produce the same ‘blue’ across distant branches of the tarantula family tree in a way that uniquely illustrates natural selection through convergent evolution.”

Unlike butterflies and birds that use nanostructures to produce vibrant colors to attract the attention of females during display courtship, tarantulas have poor vision and likely evolved this trait for a different reason. While the researchers still don’t understand the benefits tarantulas receive from being blue, they are now investigating how to reproduce the tarantula nanostructures in the laboratory.

The tarantula study is just one example of the biomimicry research being conducted in the Deheyn lab at Scripps Oceanography. In a cover article in the Nov. 10 of Chemistry of Materials, Deheyn and colleagues published new findings on the nanostructure of ragweed pollen, which shows interesting optical properties and has possible biomimicry applications. By transforming the pollen into a magnetic material with a specialized coating to give it more or less reflectance, the particle could adhere in a similar way that pollen does in nature while being able to adjust its visibility. The researchers suggest this design could be applied to create a new type of tagging or tracking technology.

Using a high-powered microscope, known as a hyperspectral imaging system, Deheyn is able to map a species’ color field pixel by pixel, which correlates to the shape and geometry of the nanostructures and gives them their unique color.

“This unique technology allows us to associate structure with optical property,” said Deheyn. “Our inspiration is to learn about how nature evolves unique traits that we could mimic to benefit future technologies.”

Here’s a link to and a citation for the paper,

Blue reflectance in tarantulas is evolutionarily conserved despite nanostructural diversity by Bor-Kai Hsiung, Dimitri D. Deheyn, Matthew D. Shawkey, and Todd A. Blackledge. Science Advances  27 Nov 2015: Vol. 1, no. 10, e1500709 DOI: 10.1126/sciadv.1500709

This paper appears to be open access.