Nature's tiny titans v. Darwin.

Small Wonders: Scientists Reveal the Secrets of Amazing Little Insects and Crustaceans
Evolution News | @DiscoveryCSC

In biology, the most amazing designs are often found in small things. In fact, it often seems that the closer you need to look, the greater the wonder. It’s as if someone set it there to hide, waiting for us. Here are some little guys worth knowing about, from among the insects and the crustaceans.

Froghoppers

“Froghopper insects can perform explosive jumps with some of the highest accelerations known among animals,” say three scientists in PNAS. The little hemipterans can withstand 400 g’s as they accelerate at 4,000 meters/second squared. They belong in a different suborder and family from the planthoppers that Evolution News wrote about in 2013, whose nymphs have gears on their legs to store elastic energy for their leaps. 

Anything with “hopper” in its name is a good place to look for design. These scientists wanted to know how froghoppers take off from smooth plant surfaces. How do they get a grip on the slippery surface? The researchers discovered a previously unreported mechanism. It got them thinking about potential applications for engineering.

Attachment mechanisms of climbing animals provide inspiration for biomimetics, but many natural adaptations are still unexplored. Animals are known to grip by interlocking claws with rough surfaces, or engaging adhesive pads on smooth substrates. Here we report that insects can use a third, fundamentally different attachment mechanism on plant surfaces. When accelerating for jumps, froghoppers produce traction by piercing plant surfaces with sharp metal-enriched spines on their hind legs, deforming the cuticle plastically and leaving behind microscopic holes, like a biological nanoindenter. This mechanism depends on the substrate’s hardness, and requires special adaptations of the cuticle at the spine tips. Piercing may represent a widespread attachment strategy among plant-living insects, promising inspiration for novel robotic grippers and climbers. 

The researchers wanted to know why froghoppers use a different mechanism than leafhoppers, which are members of a different family of hemipterans. Leafhoppers use soft pads, but they have shorter legs, which might make piercing leaf surfaces more difficult. Froghopper spines, enriched with zinc in the cuticle to make them strong, are very effective at piercing without deforming the leaf. Yet they are also finely tuned not to pierce too deep, which would inhibit rapid removal from the surface during takeoff.  This track has potential payoffs in the grocery store:

Generally, gripping smooth and plastic materials is an engineering challenge with many potential applications. Needle grippers have been used for handling soft foodstuff such as meat and cakes, but could also be adapted for handling of plastic and cardboard packaging. Studying the detailed biomechanics of penetration-based grip in natural systems and the relevant adaptations in plants and insects may provide information for the design of new biomimetic grippers.

Click Beetles

Another remarkable insect is the click beetle, able to quickly right itself without using its limbs if it falls upside down. In a class project at the University of Illinois College of Engineering , students went into the woods to collect four species of click beetles and study this unusual mechanism, thinking the trick might help robot designers create self-righting robots. Watch the video clip of their class project (but turn off the mismatched epic music; just watch the text). One student is clearly fascinated watching the bug flip high into the air and back down onto its feet. How does it work?

The beetles have a unique hinge-like mechanism between their heads and abdomens that makes a clicking sound when initiated and allows them to flip into the air and back onto their feet when they are knocked over, Alleyne said.

The students made a robotic prototype based on the hinge-snapping design. It won second place at “the international BIOMinnovate Challenge, in Paris, France — a research expo that showcases biologically-inspired design in engineering, medicine and architecture.” 

Termites

Another paper in  PNAS about the “Morphogenesis of termite mounds” finds inspiration for architectural design. Termites exhibit impressive social organization, acting almost like a distributed organism. There’s an uncanny feedback between animal and environment

Termite mounds are the result of the collective behavior of termites working to modify their physical environment, which in turn affects their behavior. During mound construction, environmental factors such as heat flow and gas exchange affect the building behavior of termites, and the resulting change in mound geometry in turn modifies the response of the internal mound environment to external thermal oscillations. Our study highlights the principles of self-organized animal architecture driven by the coupling of environmental physics to organismal behavior and might serve as a natural inspiration for the design of sustainable human architectures.

The mounds of different species “display varied yet distinctive morphologies that range widely in size and shape,” possibly due to adaptation to different environments. All of them, however, excel in the ability to “regulate mound temperature, humidity, and gas concentrations” — and they do it using natural resources, without electric thermostats or sensors. 

So-called “compass termites” always orient their mounds north/south, indicating a magnetic sense as found in salmon, sea turtles, and other very different animals. “Termite mounds are one of the most remarkable examples of self-organized animal architectures,” the authors say, “and the range of shapes and sizes that they exhibit have excited the imagination of scientists for a long time.”

Krill

These tiny crustaceans control the world, in a way. Found in all the world’s oceans, they migrate upward at night to feed, and downward in the daytime. A video by the National Science Foundation, posted by Phys.org, shows how vast numbers of krill add up to a mighty force to mix up ocean water, perhaps as significant as winds and tides. 

Stanford researcher John Dabiri and team studied them in the lab. Because krill are phototactic (moving toward light), the team could control the direction of their motions, and measure the forces they produce in a water column. The individual swimmers generate eddies that are much larger than their body sizes, and those currents add up. They concluded that millions “or trillions” of these tiny organisms, swimming together, “are playing a significant role in ocean mixing, that should impact future calculations about ocean circulation and the global climate.” 

ID proponents might look into this, and consider whether a watery exoplanet would be less habitable without this living stirring machine.

Ostracods

You could call them “sea fireflies.” Scientists at UC Santa Barbara, wanting to understand the “dazzling light displays” of ostracods, found two mechanisms at work.

Ostracods are peculiar animals. No larger than a sesame seed, these crustaceans have a clam-like shell and often lack gills. Like many sea creatures, a number of ostracods take advantage of bioluminescence to avoid predation and to attract mates….

To create their entrancing light displays, cypridinid ostracods expel a bit of mucus injected with an enzyme and a reactant, and then swim away from the glowing orb to repeat the act again. The result is a trail of fading ellipses, or will-o’-the-wisps hanging in the water column. And the length of each of these pulses is a major component of the courtship display. Some are quick like an old-fashioned flashbulb, said Hensley, while others linger in the water.

Reporter Harrison Tasoff remarks, “Evolution is a rich and dynamic process.” Yes, indeed. Since Darwin Devolves, as Michael Behe shows in his new book with that title, the ancestors of these animals must have been even better designed!

Conclusions

These are just a few among hundreds of examples of biological designs that are inspiring research at labs and universities. Complex, efficient design is found throughout the biosphere, from the tallest mammals and largest whales down to these miniature insects and crustaceans, and all the way down to the molecules in cellular nanomachines. Biomimetics is a cross-disciplinary windfall of an opportunity for mammalogists, marine biologists, botanists, entomologists, ornithologists, cell biologists, and engineers, to name a few.

As usual, evolutionary speculation in these reports varied inversely with detailed analysis into the mechanisms behind these little animals’ capabilities. Biomimetic research is also attracting funding and winning awards. So is design thinking good for science? It seems so.