Leafhoppers. You have likely seen them while working in your garden, or perhaps during a walk in a park if you have paused and looked closely. Many insects fall into this broad category, named for their ability to hop from leaf to leaf as they look for food and keep their distance from predators.
Their prevalence can make them seem fairly mundane—just “run of the mill” insects. However, many leafhoppers have caught the attention of scientists around the world, having proven themselves to be remarkable examples of mechanical engineering! Robotics experts, mechanical engineers, and even military researchers have recognized amazing features of precision engineering and technological savvy in leafhoppers, as well as structures previously noticed only in works of human design.
Let us take a moment to consider just three such features sported by these insect “innovators.”
Watching a manned rocket take off is a thrilling experience, but surely not as thrilling as riding in one. Astronauts are exposed to some extreme forces as they begin their journey. The powerful acceleration of the U.S. Space Shuttle caused a force of 3 Gs—that is, three times the force of gravity—to be exerted on the bodies of the astronauts inside. That meant that a 170-pound astronaut would sink into his seat as if he weighed 510 pounds!
Pilots of the advanced F-22 fighter jet can experience forces of up to 9 Gs—enough to make the same individual feel as if he weighs 1,530 pounds! Such forces make it necessary for the pilots to wear specialized pressure suits to keep their blood from draining from their brains.
Yet, according to the Journal of Experimental Biology, the leap of the green leafhopper Cicadella viridis generates more than 15 Gs of force on its body—nearly 16 times the force of gravity (“Bent Legs Beat Breakages During Take-Off,” April 2013). This feat grabbed the attention of Dr. Cesare Stefanini and his colleagues at the BioRobotics Institute, who wondered why such a punishing takeoff did not shatter the insect’s legs or punch a hole in its leafy launching pad.
Using high-speed cameras to record the insect’s launches, they discovered that its body muscles and leg segments work together in a remarkably coordinated action. The muscles in the thorax (the insect’s body) generate the power needed for the launch, and that force is transmitted through the femur and tibia (the two leg segments) to push against the leaf and accomplish the liftoff.
As the highly variable force generated by the insect’s muscles is transmitted through the femur, the femur twists and rotates in such a way that the force is converted into one that is smoother and more constant, pushing the tibia smoothly against the leaf and launching the insect safely airborne from its undamaged leafy perch. Without this subtle mechanical transfer and conversion—from variable force to smooth and constant force—the peak of muscular power would destroy the insect’s legs or shoot them through the leaf beneath them. Yet with this “innovation” in place, an otherwise overwhelming force is channeled into a graceful and remarkable upward launch.
Not content to let its fellow leafhopper dominate the spotlight, the species Issus coleoptratus has attracted attention for its own surprising design.
This insect, too, moves from place to place with powerful leaps. In fact, its juvenile nymph form leaps as high as 100 times its own length. (Imagine a two-foot-tall child jumping to the top of a 20-story building!) The feat takes remarkable coordination: Both legs must fire within 30 microseconds of each other—that is, within 30 millionths of one second. Otherwise, the force of their jump could launch them left or right instead of forward, which could make the difference between jumping away from a predator or straight toward it!
The insect’s nerve cells are not fast enough to ensure the legs fire in such precise synchronization, so how does the young Issus coleoptratus pull it off?
Zoologist Malcolm Burrows discovered that the insect possesses something common in the world of human engineering and design, but never before noticed in biology—a pair of gears with interlocking teeth! The teeth of the gears force each leg to move at the same time as its opposite, guaranteeing synchronized action through mechanical coordination.
Close-up photographs and scanning electron micrograph images reveal the design, which looks just like the kinds of gears one would expect to see in a watch or other man-made mechanism. But for these gears, another Designer gets all the credit. While the invention of the toothed gear was a major step forward for human engineering, it appears that leafhoppers had the jump on us and possessed such gears long before we did!
Means of locomotion are not the only area in which we see extraordinary design in ordinary leafhoppers. Some of the little critters are also masters of high-tech camouflage that would be the envy of any military in the world.
Many leafhoppers are known to produce microparticles called brochosomes, which they spread on their wings and eggs. These particles have an intricate, microscopic structure that makes them superhydrophobic, meaning that they repel water and keep the wings and eggs of the leafhoppers dry. But engineers at Penn State suspected there was an additional, previously unknown benefit to these microparticles.
They noted the similarity between the insects’ brochosomes and the synthetic microspheres they themselves were designing in their laboratory. The engineers’ microspheres are pitted with tiny holes that are similar in size to the wavelength of light. As a result, the material can “capture” up to 99 percent of light and prevent it from reflecting off of its surface.
The similarity in structure prompted the engineers to examine these microstructures under simulated insect vision. When they did so, it became clear that the water-repellent brochosome coating would also act as a high-tech “cloaking device,” making the leafhoppers and their eggs virtually invisible to predators.
As reported in Penn State News, their synthetic material requires “a rather complex five-step process using electrochemical deposition” (“Synthetic material acts like an insect cloaking device,” November 2017). Yet without a laboratory, equipment, or a team of engineers, leafhoppers accomplish this technological wonder routinely—providing themselves a defensive technology mankind is only now learning to produce.
INNOVATION ON DISPLAY
Humanity is truly intelligent, and our engineering achievements are astonishing! But our capacity to design and innovate is only a reflection of the intelligence of our own Designer, whose engineering marvels can be seen all around us if we are willing to look for them.
Next time you see a tiny insect leaping from leaf to leaf, take the time to appreciate what you are really looking at: a remarkable example of precision design and engineering, and a reminder that the Great Engineer of life still has much to teach us.