Tag Archives: insects

Nanomechanics for deciphering beetle exoskeletons

Beetles carry remarkably light yet strong armor in the form of their exoskeletons and a research team at Northwestern University (US) is looking to those beetle exoskeletons for inspiration according to a Jan. 11, 2017 news item on ScienceDaily,

What can a beetle tell us about good design principles? Quite a lot, actually.

Many insects and crustaceans possess hard, armor-like exoskeletons that, in theory, should weigh the creatures down. But, instead, the exoskeletons are surprisingly light — even allowing the armor-wearing insects, like the beetle, to fly.

Northwestern Engineering’s Horacio D. Espinosa and his group are working to understand the underlying design principles and mechanical properties that result in structures with these unique, ideal properties. This work could ultimately uncover information that could guide the design and manufacturing of new and improved artificial materials by emulating these time-tested natural patterns, a process known as bio-mimicry.

Supported by the Air Force Office of Scientific Research’s Multidisciplinary University Research Initiative (MURI), the research was featured on the cover of Advanced Functional Materials. Postdoctoral fellows Ruiguo Yang and Wei Gao and graduate student Alireza Zaheri, all members of Espinosa’s laboratory, were co-first authors of the paper. Cheryl Hayashi, professor of biology at the University of California, Riverside, was also a co-author.

A Jan. 11, 2017 Northwestern University news release, which originated the news item, expands on the theme,

Though there are more than a million species of beetles, the team is first studying the exoskeleton of the Cotinis mutabilis, a field crop pest beetle native to the western United States. Like all insects and crustaceans, its exoskeleton is composed of twisted plywood structures, known as Bouligand structures, which help protect against predators. Fibers in this Bouligand structure are bundles of chitin polymer chains wrapped with proteins. In this chain structure, each fiber has a higher density along the length than along the transverse.

“It is very challenging to characterize the properties of such fibers given that they are directionally dependent and have a small diameter of just 20 nanometers,” said Espinosa, the James N. and Nancy J. Farley Professor in Manufacturing and Entrepreneurship at Northwestern’s McCormick School of Engineering. “We had to develop a novel characterization method by taking advantage of the spatial distribution of fibers in the Bouligand structure.”

To meet this challenge, Espinosa and his team employed a creative way to identify the geometry and material properties of the fibers that comprise the exoskeleton. They cut the Bouligand structure along a plane, resulting in a surface composed of closely packed cross-sections of fibers with different orientations. They were then able to analyze the mechanics of the fibers.

“With more than a million species, which greatly vary from each other in taxomic relatedness, size, and ecology, the beetle is the largest group of insects,” Hayashi said. “What makes this research exciting is that the methods applied to the Cotinis mutabilis beetle exoskeleton can be extended to other beetle species.”

By correlating the mechanical properties with the exoskeleton geometries from diverse beetle species, Espinosa and his team plan to gain insight into natural selection and better understand structure-function-properties relationships.

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

AFM Identification of Beetle Exocuticle: Bouligand Structure and Nanofiber Anisotropic Elastic Properties by Ruiguo Yang, Alireza Zaheri, Wei Gao, Cheryl Hayashi, and Horacio D. Espinosa. Advanced Functional Materials DOI: 10.1002/adfm.201603993 Version of Record online: 27 DEC 2016

© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

This paper is behind a paywall.

Artists classified the animal kingdom?

Where taxonomy and biology are concerned, my knowledge begins and end with Carl Linnaeus, the Swedish scientist who ushered in modern taxonomy. It was with some surprise that I find out artists also helped develop the field. From a June 21, 2016 news item on ScienceDaily,

In the sixteenth and seventeenth centuries artists were fascinated by how the animal kingdom was classified. They were in some instances ahead of natural historians.

This is one of the findings of art historian Marrigje Rikken. She will defend her PhD on 23 June [2016] on animal images in visual art. In recent years she has studied how images of animals between 1550 and 1630 became an art genre in themselves. ‘The close relationship between science and art at that time was remarkable,’ Rikken comments. ‘Artists tried to bring some order to the animal kingdom, just as biologists did.’

A June 21, 2016 Universiteit Leiden (Leiden University, Netherlands) press release, which originated the news item, expands on the theme,

In some cases the artists were ahead of their times. They became interested in insects, for example, before they attracted the attention of natural historians. It was artist Joris Hoefnagel who in 1575 made the first miniatures featuring beetles, butterflies and dragonflies, indicating how they were related to one another. In his four albums Hoefnagel divided the animal species according to the elements of fire, water, air and earth, but within these classifications he grouped animals on the basis of shared characteristics.

Courtesy: Universiteit Leiden

Beetles, butterflies, and dragonflies by Joris Hoefnagel. Courtesy: Universiteit Leiden

The press release goes on,

Other illustrators, print-makers and painters tried to bring some cohesion to the animal kingdom.  Some of them used an alphabetical system but artist Marcus Gheeraerts  published a print as early as 1583 [visible below, Ed.] in which grouped even-toed ungulates together. The giraffe and sheep – both visible on Gheeraerts’ print – belong to this species of animals. This doesn’t apply to all Gheeraerts’ animals. The mythical unicorn, which was featured by Gheeraerts, no longer appears in contemporary biology books.

Wealthy courtiers

According to Rikken, the so-called menageries played an important role historically in how animals were represented. These forerunners of today’s zoos were popular in the sixteenth and seventeenth centuries particularly among wealthy rulers and courtiers. Unfamiliar exotic animals regularly arrived that were immediately committed to paper by artists. Rikken: ‘The toucan, for example, was immortalised in 1615 by Jan Brueghel the Elder, court painter in Brussels.’  [See the main image, Ed.].’

In the flesh

Rikken also discovered that the number of animals featured in a work gradually increased. ‘Artists from the 1570s generally included one or just a few animals per work. With the arrival of print series a decade later, each illustration tended to include more and more animals. This trend reached its peak in the lavish paintings produced around 1600.’ These paintings are also much more varied than the drawings and prints. Illustrators and print-makers often blindly copied one another’s motifs, even showing the animals in an identical pose. Artists had no hesitation in including the same animal in different positions. Rikken: ‘This allowed them to show that they had observed the animal in the flesh.’

Even-toed ungulates by Marcus Gheeraerts. Courtesy: Leiden Universiteit

Even-toed ungulates by Marcus Gheeraerts. Courtesy: Leiden Universiteit

Yet more proof or, at least, a very strong suggestion that art and science are tightly linked.

Sciences Goes to the Movies closes out season one with zombies and opens season two with nanotechnolgy

Thanks to David Bruggeman’s March 9, 2016 posting on his Pasco Phronesis blog for the latest about ‘Science Goes to the Movies’,

The 13th episode of Science Goes to the Movies is now available online, and showing some restraint, the show waited until the end of its first season to deal with zombies.

In other show news, the second season will premiere on CUNY [City University of New York] TV March 18th [2016].  It will focus on nanotechnology.

You can find the 13th episode (running time is almost 30 mins.) embedded in David’s post or you can go to the Science Goes to the Movies webpage on the City University of New York (CUNY) website for the latest video and more information about the episode,

In episode #113 of Science Goes to the Movies, series co-hosts Dr. Heather Berlin and Faith Salie talk with Mark Siddall – a curator at the American Museum of Natural History and President of the American Society of Parasitologists – about zombies!

… Siddall describes different types of parasites that manipulate behavior in a host in order to complete a life cycle or other essential task – including a type of “Dementor” wasp, named after the monster in Harry Potter books, that changes behavior in a cockroach by stinging it. Whether or not zombifying parasites have a taste for brains is also considered, with reference to a species that takes over the bodies of ants, replaces their brains, and uses the ant to complete its life cycle, and The Guinea Worm, a parasite that targets humans for their own reproduction. Siddall then distinguishes between parasites and viruses and explains their similarities.

The Haitian voodoo practice of ingesting neurotoxins to create the effect of “waking from the dead” provides the basis for the next part of the discussion. Dr. Berlin defines neurotoxins and how they work in the brain to block neurons from firing. Tetrodotoxin, in particular, is explained as having a zombifying effect on humans in that its overall paralysis doesn’t affect the brain or the heart, leaving a person fully conscious throughout.

The Wade Davis [emphasis mine] book, The Serpent and The Rainbow, is brought into the discussion, as well as a story about a man kept in a zombie state for two years by ingesting a combination of neurotoxins and hallucinogens. Dr. Berlin breaks down the plausibility of the story and introduces the idea of the “philosopher zombie,” whose zombie status is more conceptual in nature.

28 Days Later and World War Z are discussed as examples of zombie movies in which the cause of the apocalypse is a zombie infection, and Siddall shares news about a cancer with contagious qualities. A recent Centers for Disease Control ad campaign, warning people to prepare for the zombie apocalypse, is mentioned and the real-life potential for human zombies, given the creativity of evolution, makes for the final topic of the show. Before finishing, though, Dr. Berlin and Siddall each share an idea for an original zombie movie.

Written and Produced by Lisa Beth Kovetz.

Wade Davis is a Canadian anthropologist who now teaches at the University of British Columbia.

Should you care to search, you will find a number of posts concerning zombies on this blog.

Controlling cyborg insects

After writing about cyborg insects and their possible use in emergency situations in my Nov. 23, 2011 posting, I started wondering how the insects could be made to dig down into the earth to find people trapped underground, etc. As it turns out, scientists have already been working on that problem, from the Jan. 6, 2012 news item on physorg.com,

An insect’s internal chemicals can be converted to electricity, potentially providing power for sensors, recording devices or to control the bug, a group of researchers at Case Western Reserve University report.

The finding is yet another in a growing list from universities across the country that could bring the creation of insect cyborgs – touted as possible first responders to super spies – out of science fiction and into reality. In this case, the power supply, while small, doesn’t rely on movement, light or batteries, just normal feeding.

“It is virtually impossible to start from scratch and make something that works like an insect,” said Daniel Scherson, chemistry professor at Case Western Reserve and senior author of the paper.

“Using an insect is likely to prove far easier,” Scherson said. “For that, you need electrical energy to power sensors or to excite the neurons to make the insect do as you want, by generating enough power out of the insect itself.”

The key to converting the chemical energy is using enzymes in series at the anode.

The first enzyme breaks the sugar, trehalose, which a cockroach constantly produces from its food, into two simpler sugars, called monosaccharides. The second enzyme oxidizes the monosaccharides, releasing electrons.

The current flows as electrons are drawn to the cathode, where oxygen from air takes up the electrons and is reduced to water.

After testing the system using trehalose solutions, prototype electrodes were inserted in a blood sinus in the abdomen of a female cockroach, away from critical internal organs.

The researchers found the cockroaches suffered no long-term damage, which bodes well for long-term use.

More technical details are available in the news item although I notice there is no mention of ethics. I’m happy to see that there doesn’t seem to be any long-term damage to any of the beasties they’ve tested so far but should we really take control of them in this way?

Oil in the Gulf of Mexico, science, and not taking sides

Linda Hooper-Bui is a professor in Louisiana who studies insects.She’s also one of the scientists who’s been denied access to freely available (usually) areas in the Gulf of Mexico wetlands. She and her students want to gather data for examination about the impact that the oil spill has had on the insect populations. BP Oil and the US federal government are going court over the oil spill and both sides want scientific evidence to buttress their respective cases. Scientists wanting access to areas controlled by either of the parties are required to sign nondisclosure agreements (NDAs) by either BP Oil or the Natural Resource Damage Assessment federal agency. The NDA’s extend not just to the publication of data but also to informal sharing.

From the article by Hooper-Bui in The Scientist,

The ants, crickets, flies, bees, dragon flies, and spiders I study are important components of the coastal food web. They function as soil aerators, seed dispersers, pollinators, and food sources in complex ecosystems of the Gulf.

Insects were not a primary concern when oil was gushing into the Gulf, but now they may be the best indicator of stressor effects on the coastal northern Gulf of Mexico. Those stressors include oil, dispersants, and cleanup activities. If insect populations survive, then frogs, fish, and birds will survive. If frogs, fish, and birds are there, the fishermen and the birdwatchers will be there. The Gulf’s coastal communities will survive. But if the bugs suffer, so too will the people of the Gulf Coast.

This is why my continued research is important: to give us an idea of just how badly the health of the Gulf Coast ecosystems has been damaged and what, if anything, we can do to stave off a full-blown ecological collapse. But I am having trouble conducting my research without signing confidentiality agreements or agreeing to other conditions that restrict my ability to tell a robust and truthful scientific story.

I want to collect data to answer scientific questions absent a corporate or governmental agenda. I won’t collect data specifically to support the government’s lawsuit against BP nor will I collect data only to be used in BP’s defense. Whereas I think damage assessment is important, it’s my job to be independent — to tell an accurate, unbiased story. But because I choose not to work for BP’s consultants or NRDA, my job is difficult and access to study sites is limited.

Hooper-Bui goes on to describe a situation where she and her students had to surrender samples to a US Fish and Wildlife officer because their project (on public lands therefore they should have been freely accessible) had not been approved. Do read the article before it disappears behind a paywall but if you prefer. you can listen to a panel discussion with her and colleagues Christopher D’Elia and Cary Nelson on the US National Public Radio (NPR) website, here. One of the people who calls in to the show is another professor, this one from Texas, who has the same problem collecting data. He too refused to sign any NDAs. One group of nonaligned scientists has been able to get access and that’s largely because they acted before the bureaucracy snapped into place. They got permission (without having to sign NDAs) while the federal bureaucracy was still organizing itself in the early days of the spill.

These practices are antithetical to the practice of science. Meanwhile, the contrast between this situation and the move to increase access and make peer review a more open process (in my August 20, 2010 posting) could not be more glaring. Very simply, the institutions want more control while the grassroots science practitioners want a more open environment in which to work.

Hooper-Bui comments on NPR that she views her work as public service. It’s all that and more; it’s global public service.

What happens in the Gulf over the next decades will have a global impact. For example, there’s a huge colony of birds that make their way from the Gulf of Mexico to the Gaspé Peninsula in Québec for the summer returning to the Gulf in the winter.  They should start making their way back in the next few months. Who knows what’s going to happen to that colony and the impact this will have on other ecosystems?

We need policies that protect scientists and ensure, as much as possible, that their work be conducted in the public interest.