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Design Wonders in a Ladybird Beetle

Evolution News

You might think scientists would have all the common critters figured out by now. Yet there is more design in your garden bugs and other insects than anyone could imagine.

What child hasn’t picked up a ladybug, aka ladybird beetle, and quoted the nursery rhyme, “Ladybird, ladybird, fly away home” as she watched it take off into the air? Or perhaps we are dating ourselves. Anyway, people like ladybird beetles because of their bright red colors and spots, and the fact that they eat garden pests. Now, thanks to these favorite insects, more design evidence has come to light.

As David Klinghoffer noted here briefly already, the credit goes to the Japanese; what five Japanese researchers found during their “Investigation of hindwing folding in ladybird beetles by artificial elytron transplantation and microcomputed tomography” will be of interest to all. The paper in the Proceedings of the National Academy of Sciences (PNAS) presents design features in these common little spotted beetles that are making robot engineers stand up and take notice.

True beetles are members of order Coleoptera (sheath-wing), indicating their flight wings are protected under hard shields of chitin, called elytra. They are not really “ladybugs” as Americans usually call them, because they are not true bugs (Hemiptera). On the other hand, they’re not birds either, so the misnomer is forgivable. What was discovered in ladybirds undoubtedly applies to many other flying beetles. Ladybirds lift their elytra, unfold their wings, and take off. We’ve all witnessed that, but what actually goes on? How does the beetle unfold and refold those delicate wings? A video is worth a thousand words: watch what happens in this high-speed video clip posted on New Scientist:

As shown in the captions, the beetle uses an intricate method of origami to fold its wings into a Z-shape for compact storage under the shield. Since there are no hinges in the membranes, it just pops back into shape when the elytra are lifted.

They found that prominent veins along the edge of the wings allow creases to form and fold the wings away in a complex, origami-like shape. A bend in the wing can drift down a vein as it gets folded, but the wing is ready to spring back to a rigid form when the elytra open.

“The wing frame has no joint,” Saito says. “Usually, transformable structures require a lot of parts, including joints and rigid parts. Ladybirds effectively use flexibility and elastic behaviour in the structures and achieve complex transformation by very simple structures.” [Emphasis added.]

NASA often has to perform similar maneuvers, such as extending solar panels out from folded storage. Needless to say, they don’t use Darwinism to do it. Spacecraft engineers will undoubtedly take a good look at the humble ladybird beetle’s folding mechanism to figure out better ways to get delicate parts to unfurl and refold in space. Since a ladybird can live from two to three years (National Geographic), it does it correctly thousands of times!

Surprisingly, ladybirds fold their wings after the elytra close. The elytra must play a role in the folding process. To see what was going on, the researchers built a transparent replacement elytron out of resin to look inside while the beetle folded its wing. High-speed cameras allowed for watching the process at unprecedented detail in slow motion.

The authors noticed that what they were witnessing was an elegant solution to an optimization problem. The beetle faces two competing constraints: stability and deformability. Folding requires the latter, but flying requires the former. What’s the best compromise?

This study demonstrates how ladybird beetles address these two conflicting requirements by an unprecedented technique using artificial wings. Our results, which clarify the detailed wing-folding process and reveal the supporting structures, provide indispensable initial knowledge for revealing this naturally evolved optimization system. Investigating the characteristics in the venations and crease patterns revealed in this study could provide an innovative designing method, enabling the integration of structural stability and deformability, and thus could have a considerable impact on engineering science.

Ah, yes, the E-word again. It’s a “naturally evolved optimization system” that can give humans “an innovative designing method” to use for intelligent design. The word evolution clutters an otherwise fascinating paper with useless Darwinian verbiage that is never explained:

  • Ladybird beetles have successfully resolved these two conflicting requirements, resulting in the evolution of relatively thick veins with decent strength properties while achieving sufficiently compact wing folding with two folding lines in the longitudinal direction of the wing.
  • The detailed wing-folding mechanism revealed in the present study is expected to facilitate understanding of the optimization process that has developed during the course of evolution….

But that’s it. Just three mentions of evolution. Design and engineering merited seven mentions. As usual, evolution is taken for granted as a designer. References to the “creation myth of our culture,” as Phillip Johnson calls it, seem obligatory for scientific papers, but they contribute nothing to the meat of the science.

We’ve discussed optimization in our list of examples of Intelligent Design in Action. Stephen Meyer illustrates the principle by a laptop: finding the “sweet spot” between weight, energy requirements, portability, storage, power, heat, and other constraints. Optimization explains how intelligent design extends to the whole, not just the parts. A laptop could be designed with a 500-terabyte hard drive, for example, but it wouldn’t be able to run for long, and it would be less portable. The composite design that provides the best overall benefit is the goal of optimization.

Watch all three video clips in the open-access paper, then look at the illustration in an NPR article to see how complex the origami is. The wing makes some ten creases to achieve its tight fold. One would think all those creases would weaken the wing, but the beetle solves that problem, too. Ever used a spring-loaded tape measure?

The biggest challenge for ladybird beetles is that they are required to embed the two transverse folding lines (PTF and ATF) on the anterior margin, which acts as the main support structure of the hindwing during flight. Simple articulations or positionally fixed compliant hinges in this area may cause a considerable decrease in the stiffness and strength of the wing. Our results show that ladybird beetles solve this problem by using tape spring-like veins as the main wing-supporting structures. A tape spring is a thin elastic strip with a curved cross-section that is commonly known as a carpenter tape. This structure becomes elastically stable when it is extended and can be stored into a compact form only by elastic folding; therefore, it is widely used in the extension booms and hinges of space-deployable structures. Fig. 4 presents a schematic of the functions of tape spring-like veins in wing folding/unfolding. These veins are stabilized in the unfolded shape and can confer sufficient stiffness for flight (Fig. 4A).

The structure’s “elastic force caused by the resilience in the localized folds is considered to enable rapid wing deployments in ladybird beetles,” they say. Anyone who has watched one take off from the hand knows that the whole deployment is, indeed, very rapid. The ladybird’s rapid unfolding mechanism may actually help you on the next rainy day:

The detailed wing-folding mechanism revealed in the present study is expected to facilitate understanding of the optimization process that has developed during the course of evolution, which can elucidate the innovative design method enabling the integration of both structural stability and deformability. Immediate applications may be deployable structures, including space-deployable structures represented by solar array paddles and antenna reflectors of satellites, wings of carrier-based aircrafts, and many articles of daily use with a deforming function (e.g., umbrellas, fans).

The authors considered that the beetle may also use hydraulics — pumping fluid into the veins to stiffen the wings the way emerging butterflies do. They weren’t able to confirm that in this paper, but hold it out as a possibility for future study.

In short, we see multiple independent parts working together to make the ladybird wing system work:

  • Veins with the right tape spring-like shape
  • Deformable membrane material
  • A pre-programmed origami-like folding pattern
  • Elytra the right size and shape to open and close
  • Wings capable of flight, with all that entails
  • Behaviors programmed in the beetle’s tiny brain
  • Energy for the wings obtainable from food

To save space, we won’t get carried away adding to the list, which could easily extend from the cellular and genetic level all the way to the whole organism. Suffice it to say that the blind, unguided “course of evolution” is wholly inadequate to account for the observations.

Photo: Ladybird beetle, by Gilles San Martin (Coccinella magnifica) [CC BY-SA 2.0], via Wikimedia Commons.