Tag Archives: beetles

The inside scoop on beetle exoskeletons

In the past I’ve covered work on the Namib beetle and its bumps which allow it to access condensation from the air in one of the hottest places on earth and work on jewel beetles and how their structural colo(u)r is derived. Now, there’s research into a beetle’s body armor from the University of Nebraska-Lincoln according to a Feb. 22, 2017 news item on ScienceDaily,

Beetles wear a body armor that should weigh them down — think medieval knights and turtles. In fact, those hard shells protecting delicate wings are surprisingly light, allowing even flight.

Better understanding the structure and properties of beetle exoskeletons could help scientists engineer lighter, stronger materials. Such materials could, for example, reduce gas-guzzling drag in vehicles and airplanes and reduce the weight of armor, lightening the load for the 21st-century knight.

But revealing exoskeleton architecture at the nanoscale has proven difficult. Nebraska’s Ruiguo Yang, assistant professor of mechanical and materials engineering, and his colleagues found a way to analyze the fibrous nanostructure. …

A Feb. 22, 2017 University of Nebraska-Lincoln news release by Gillian Klucas (also on EurekAlert), which originated the news item, describes skeletons and the work in more detail,

The lightweight exoskeleton is composed of chitin fibers just around 20 nanometers in diameter (a human hair measures approximately 75,000 nanometers in diameter) and packed and piled into layers that twist in a spiral, like a spiral staircase. The small diameter and helical twisting, known as Bouligand, make the structure difficult to analyze.

Yang and his team developed a method of slicing down the spiral to reveal a surface of cross-sections of fibers at different orientations. From that viewpoint, the researchers were able to analyze the fibers’ mechanical properties with the aid of an atomic force microscope. This type of microscope applies a tiny force to a test sample, deforms the sample and monitors the sample’s response. Combining the experimental procedure and theoretical analysis, the researchers were able to reveal the nanoscale architecture of the exoskeleton and the material properties of the nanofibers.

Yang holds a piece of the atomic force microscope used to measure the beetle's surface. A small wire can barely be seen in the middle of the piece. Unseen is a two-nano-size probe attached to the wire, which does the actual measuring.

Craig Chandler | University Communication

Yang holds a piece of the atomic force microscope used to measure the beetle’s surface. A small wire can barely be seen in the middle of the piece. Unseen is a two-nano-size probe attached to the wire, which does the actual measuring.

They made their discoveries in the common figeater beetle, Cotinis mutabilis, a metallic green native of the western United States. But the technique can be used on other beetles and hard-shelled creatures and might also extend to artificial materials with fibrous structures, Yang said.

Comparing beetles with differing demands on their exoskeletons, such as defending against predators or environmental damage, could lead to evolutionary insights as well as a better understanding of the relationship between structural features and their properties.

Yang’s co-authors are Alireza Zaheri and Horacio Espinosa of Northwestern University; Wei Gao of the University of Texas at San Antonio; and Cheryl Hayashi of the University of California, Riverside.

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

Exoskeletons: AFM Identification of Beetle Exocuticle: Bouligand Structure and Nanofiber Anisotropic Elastic Properties by Ruiguo Yang, Alireza Zaheri,Wei Gao, Charely Hayashi, Horacio D. Espinosa. Adv. Funct. Mater. vol. 27 (6) 2017 DOI: 10.1002/adfm.201770031 First published: 8 February 2017

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.