insects

Cool Insect Tricks — Think Before You Swat

National Geographic says, “Without Bugs, We Might All Be Dead.” We shouldn’t despise the creatures that help keep our planet functioning. Even if a few cause problems, they are overwhelmed by vast numbers of other insects that play key roles in the ecology. Just consider:

There are 1.4 billion insects for each one of us. Though you often need a microscope to see them, insects are “the lever pullers of the world,” says David MacNeal, author of Bugged. They do everything from feeding us to cleaning up waste to generating $57 billion for the U.S. economy alone. [Emphasis added.]

MacNeal was awestruck when he studied the roles of insects for his book. He commented:

Individually, insects are not incredibly interesting, unless you get down on the ground or view them under a microscope to look at their complexity. But they are the invisible force working throughout the world to keep it running.

Let’s take a look at the complexity of just a few of these small wonders.

Visual Systems

First of all, we need to unlearn the idea that insects don’t see very well through those compound eyes. Some conceptions of pixelated vision through thousands of facets have assumed it’s like looking around in a hall of mirrors or through a kaleidoscope. Not so. Phys.org reports, “Insects can see the world in much finer resolution than previously thought.” New research from the University of Sheffield finds that “Insects have much better vision and can see in far greater detail than previously thought.” It required new instrumentation to reveal the secret:

Unlike in the human eye, the thousands of tiny lenses, which make the compound eye’s characteristic net-like surface, do not move, or cannot accommodate. But the University of Sheffield researchers found that photoreceptor cells underneath the lenses, instead, move rapidly and automatically in and out of focus, as they sample an image of the world around them. This microscopic light-sensor “twitching” is so fast that we cannot see it with our naked eye. To record these movements inside intact insect eyes during light stimulation, the researcher had to build a bespoke microscope with a high-speed camera system.

The resulting “hyperacute” vision is finely tuned, they found, to the insect’s natural behaviors. It’s so good, in fact, that Stanford engineers are trying to imitate it for solar cell design, Science Daily says. They are “inspired by the compound eye of the fly,” with its built-in redundancy and durability. The U.K. scientists also believe that insect eye design “could also be used in industry to improve robotic sensors.”

Navigation Systems

With those high-resolution eyes, the humble fly comes equipped with sophisticated navigation systems, too. Another article in Science Daily discusses work at RIKEN Brain Science Institute in Japan. A team of scientists built a “superfly flight simulator” to discover that “landmark locations are processed separately in the fly brain from self-motion.”

Scientists have worked primarily with birds and mammals to show this ability, but consider how much more sophisticated it must be to work in a tiny fruit fly. It’s a marvel of micro-miniaturization; “despite its much simpler and tiny brain, it has an amazing ability to zero in on fruit and avoid being squashed by irritated picnickers,” the article says.

To isolate the neurons involved and monitor their activity, the scientists had to fix a fly’s head in the simulator and manipulate a projected scene whenever the insect flapped its wings. This allowed them to monitor the insect’s navigation through a virtual space. What they found was an elegant, compact solution to the problem of identifying landmarks while remembering landmarks encountered moments earlier.

The calcium imaging showed that a part of the fly brain called the bulb carried multiple types of information needed for navigation.

Close examination revealed that within the bulb, the information was physically separated from each other. For example, one group of bulb neurons carried memories of landmark locations, while another group carried information about the fly’s ongoing position and maneuvers….

The separate bulb regions turn out to be part of two separate pathways that form independent neural circuits. This type of organization might ensure that many types of information can flow without interference, while at the same time minimizing space.

It’s enough to make you think before you swat. More:

“Insects navigate the environment efficiently with economical brains,” notes [Hiroshi M.] Shiozaki, “and understanding these biological principles will be useful not only for the field of neuroscientists, but also for engineers and roboticists who are developing small navigating robots.”

Communication Systems

A paper in the Proceedings of the National Academy of Sciences (PNAS) presumes to discuss the “evolution of social communication,” but actually reveals astonishing complexity in the chemical signaling between social insects — particularly ants. Those brief kisses we see ants doing as they cross our kitchens in organized trails are not just for love. They involve sophisticated olfactory organs and programmed responses to a wide variety of chemicals, so that each ant knows where to go and what to expect.

A figure in the paper shows parts of the olfactory system: antennal lobe, olfactory receptors on olfactory neurons, central body, lateral horn, mushroom bodies, optic lobe, and more — all arranged for efficient information sharing. Readers may remember the astonishing animation of olfactory complexity in the salmon featured in Living Waters (see it here). Now imagine packing that functionality into an ant’s head! The writers in PNAS indicate that much more research will be required, including advances in “dedicated subsystem theory” in order to bring “the field closer to a deep understanding of the neuro-ethology of social communication.”

One More Cool Trick

Try this challenge: Take a hair and drill a hole into a fig with it. Can’t be done? Wasps do it all the time. Female wasps have a long, slender tool called an ovipositor (egg positioner). With this unlikely device, about 15 microns in diameter, they drill into the hard rinds of fruit and send their eggs down a channel in the middle. And they do it with precision steering during the drilling operation. How on earth?

Scientists publishing in PNAS examined this trick. In “Mechanisms of ovipositor insertion and steering of a parasitic wasp,” they realized that “Using slender probes to drill through solids is challenging, but desirable, due to minimal disturbances of the substrate.” The species they studied drills into other insects rather than into fruit, but the challenge is similar if not greater.

We show that wasps are able to probe in any direction with respect to their body orientation and use two methods of insertion. One of the methods implies a minimal net pushing force during drilling. Steering was achieved by adjusting the asymmetry of the probe’s distal end. Knowledge on probing mechanisms of wasps is important for the understanding of the hymenopteran evolution and for the development of minimally invasive steerable probes.

A short video on IFL Science shows a fig wasp using its ovipositor in action. The “drill bit” of the ovipositor is hardened with zinc and includes sensory structures that guide the wasp to the best spot for drilling. That implies neural communication all the way back to the wasp’s brain — even more to pack into a hair-like drilling tool.

Whether or not studying these microscopic drills will further “understanding of hymenopteran evolution”, research must begin by understanding the design. The authors seem to admit that as they detail the structure of the wasp ovipositor:

The general morphology of the ovipositor is similar across all wasp species; it consists of four elements, called valves, of which two are often merged such that three functional valves remain (Fig. 1). In most species, the distal part of the ovipositor is morphologically distinct, which we will refer to as the tip. The valves can slide along each other and do not get dislocated under natural conditions, because they are longitudinally connected via a tongue-and-groove mechanism. The ovipositor and the “wasp waist,” a constriction of the body between the first and second abdominal segment, are essential in probing behavior and are therefore considered to be instrumental in the evolution of the order. The shape, structure, and mechanical properties of the ovipositors are putatively adapted to the substrates into which the animals need to probe, and because both substrates and hosts are so diverse, this might have resulted in high species diversification of the hymenopterans. However, to understand the observed diversity in the ovipositor shapes, understanding of the probing mechanics is essential.

So we “might” learn about diversification, but it is “essential” to study the mechanics (i.e., the engineering design) of the probe first. And if we do that, we might be able use that information “to improve man-made steerable probes” which, of course, are made by intelligent design. It doesn’t appear Darwinian evolution has much to contribute to the story except, perhaps, a narrative gloss.

Conclusion

For each of these Cool Insect Tricks, we find human engineers salivating over the designs they see (whether they acknowledge that the design is intelligent or not) to the point they want to imitate them. If plagiarism is the sincerest form of flattery, we notice that despite the hat tips to Darwin here and there, intelligent design — not Darwinian evolution — is getting all the fawning attention.

Source: Cool Insect Tricks — Think Before You Swat | Evolution News

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