Spineless Samurai

When the annual cicadas emerge each summer their tymbals vibrate at arboreal drumming circles all over town.  The beats bounce and reverberate against hard city surfaces; during a crescendo, I swear I can feel the buildings and sidewalks pulsing like wings, like a heart. Yet, despite the percussive nature of this invertebrate orchestra, to my ears the cicada’s summer song evokes the kokyū—a traditional Japanese string instrument played with a bow.

This may be due to the fact that I imagine cicadas as miniature ronin, masterless six-legged samurai, stoic and single-minded, clad in intricately constructed armor of lacquered plates and scales. Of course, several beetle species call to mind this 12th-century warrior class, and I’m not the only one to see the resemblance. Rhinoceros beetles (Allomyrina dichotomy), for example, are known in Japan as a kabutomushimushi, the Japanese word for insect, and kabuto, which refers to the helmet worn by samurai (and the inspiration for Darth Vader’s visage).

It don’t know if it’s an example of the sincerest form of flattery or an unconscious imitation, but biomimicry—biological features or processes used as inspiration for beneficial products and practices— is an old technique that’s experiencing resurgence. Humans have long taken cues from the successful strategies of other animals. Indigenous cultures incorporated the characteristics of nonhuman animals into hunting tactics and rituals; composers have used all manner of musical instruments to simulate birdcalls and other nature sounds; superheroes like Spider-Man and Batman are pretty shameless about co-opting the special powers of their totem animals.

Then there’s warcraft. It’s hard to miss the resemblance between certain insects and the body armor worn by human warriors. From my perspective, there’s a natural synergy between invertebrates, who need a rigid external sheath for support and protection due to the absence of an internal skeleton, and Homo sapiens, who need prosthetic exoskeletons to protect our vulnerable bodies from the increasingly deadly technology imagined and fashioned by members of our own species—first flint arrowheads, then copper maces, bronze spears and daggers, iron javelins and swords, cannons and shrapnel, steel rifles and handguns, and eventually weapons that make any kind of armor irrelevant.

Chemical warfare is common in the insect world, and humans have readily adopted the same strategy against both macroscopic and microscopic opponents. In human enterprises, poisons do generally deliver short-term success; however, the initial win is usually followed by long-term health and environmental losses. This is particularly true when chemistry is used against presumed enemies with high reproduction rates… for example, insects and bacteria.

In most biological populations, there will usually be at least a few members strong or lucky enough to survive the application of toxins. Those individuals become the progenitors of the next generation, passing along their protective genetic code and, over time, rendering the chemical weaponry powerless. That’s how natural selection produces organisms well suited to their environment, and that’s why chemical deterrents always have a limited shelf life… against insects and bacteria, anyway. Less than 150 years after the introduction of antibiotics, hospitals and medical personnel are fighting resistant bacteria, including methicillin-resistant Staphylococcus aureus (MRSA) and multi-drug-resistant Mycobacterium tuberculosis (MDR-TB), and attempting to do so with a limited alternate arsenal.

As a result, biomimicry is shrinking to nano-scale. Researchers are investigating new ways to protect human bodies from bacterial enemies, and certain insects have proven to be adept at mechanical antibacterial warfare. Think samurai on a microbial level.

In 2013, a team of researchers from Australia and Spain discovered that evolution has armed the clanger cicada (Psaltoda claripennis) with an elegantly simple defense against infection worthy of a kendo master. Clanger wings are covered with nano-pillars—aka tiny spikes.

Initially, it was assumed this pointed texture worked like a bed of nails—a hapless bacterium lands on the wing, stretching and sagging into the crevices between the spikes, and as gravity does its thing the pathogen’s skin tears, rendering it incapable of reproduction. Earlier this year, though, a group of Australian and Nigerian researchers proposed that truth is, once again, stranger than fiction… or at least as inventive as a movie villain.

Bacteria adhere to surfaces and each other by secreting finger-like structures called extracellular polymeric substances (EPS). These natural polymers allow the organisms to form biofilms on plant roots and fruit, fish and boat hulls, teeth and gums, plumbing pipes and medical catheters, even hot alkaline spring waters and glaciers—in other words, nearly any surface we know of except a nano-textured insect wing.

If the bacteria on a clanger cicada wing would stay put, they would likely deform but survive. If they move, though, those pillars subject the EPS to shear forces, ripping the external membrane and causing the bacteria to deflate like a balloon due to fatal leakage of the cell’s contents.

Regardless of how these nano-textured surfaces (NTS) kill, their potential as models for developing chemical-free, non-toxic antibacterial materials is undeniably exciting.  One of the first proposed products to utilize NTS was a coating that could be applied to countertops, doorknobs, railings, bus straps, subway poles, sinks, commodes, and even money. An Australian manufacturer of medical implants has acquired the patent, seeing potential for using this technology to reduce the chance of post-surgical infection. Since the killing mechanism is mechanical, devices coated with nano-textures could bypass the clinical approval processes required for chemical treatments, reducing the time and cost to bring these products to market.

Additional research has revealed that clanger cicadas aren’t the only winged insects armed with antibacterial nano-patterns, nor are they the most efficient.  The cicada’s NTS only kills gram-negative bacteria, but the wings of a fiery skimmer dragonfly (Orthetrum villosovittatum) have an NTS that is equally effective at killing both gram-negative and gram-positive pathogens. 

The nano-scale needles formed by black silicon have been tested in the lab and appear to have antibacterial properties similar to those of dragonfly wings. However, scientists aren’t yet sure why nano-patterned wings provides such a powerful defense, or how to replicate it for commercial use. That should come as no surprise given the nature of warfare, on any scale. It’s the Way of the Sword, and a samurai never reveals all of his secrets.

Every summer, people complain about cicadas but if insect wing nano-pillars become the next penicillin they may change their tune. Personally, I find the droning soundtrack soothing. I like knowing that, aided by sodium-yellow streetlights, spineless samurai are keeping watching through the night. Their kokyū lullaby floats past the gingko tree leaves, slips through my window screen, and into my dreams.


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© 2018 Next-Door Nature. First published at the Center for Humans and Nature’s City Creatures blog.  Reprints welcomed with written permission from the author. Thanks to the following photographers who made their work available through the Creative Commons license: Boaz Ng, Walters Art Museum, NFG photo, Mike BitzenhoferPaul Balfe, and tami abigador pearson.

Hammers and Hydrangeas

Sometimes green means stop, look, and pay attention.

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Productivity.  A word that has long enjoyed favored status in U.S. culture. Americans are always trying to do more work in less time so we can… do even more work. We purchase time-saving apps and appliances and then fill the promised free-time that closed the deal with new projects and expectations.
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As the saying goes, when you’re a hammer everything looks like a nail. Of course, that assume you stop the work of pounding away occasionally to look around.
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I aspire to a zen “be here now” life but most days I miss the mark by a wide margin. Instead, I hammer down each nail on my to-do list, usually thinking about the next task or the one after that before completing the current one (and often ending up with a swollen thumb as a result). Yesterday was no exception.
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Until, suddenly, it was.
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Exiting my car with plastic shopping bag handles queued up along my forearms I charged down the sidewalk, mental blinders on, jaw set. Still, I did notice the row of tall limelight hydrangeas that hug my red brick building slouching beneath their load of heavy, fragrant, pale chartreuse blooms buzzing with activity.  “Honey bees,” I assumed dismissively, since a nearby restaurant keeps several hives, and continued on without breaking my stride.
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Then I was blinded by the light of a sunbeam reflecting off an iridescent copper-green carapace.
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I stopped in my tracks, oblivious to the increasing numbness in my hands, and watched one green June beetle (Cotinis nitida), then several more, stumble drunkenly around and through the blossoms. Glancing at other blooms I saw all kinds of colorful insects had shown up for the banquet, including other beetles and bees, butterflies, moths, flies, spiders, and wasps.  The realization that I was, yet again, missing my life for the sake productivity hit me over the head like a ball-peen.
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Time to take a deep breath and smell the hydrangeas. I rushed inside, left my groceries in a heap on the kitchen table, hurried back downstairs, out the door…
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and…
             slowed…
                                 waaaaay…
                                                          down.
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I spent the next hour losing track of time while I conducted an informal census of bug life in the flower gardens around my building and neighborhood. My goal was enjoyment, not identification. Eyes opened wide. Really seeing.
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composite greens
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red-orange-yellow composite
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purple composite
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bright composite
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How easy it is to forget that being unproductive is sometimes the most important work of all.
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© 2015 Next-Door Nature—no reprints without written permission from the author (I’d love for you to share my work  but please ask). Green June beetle photo by the author (CCL).  Thanks to these photographers for making their work available on Flickr through a Creative Commons license: Jon K.;  Bill Bumgarner; Shellie Gonzalez; Andy Reago & Chrissy McClarren; doni19; Vincent Parsons; Photoguyinmo Swatzell; Dave Thomas; and USFWSmidwest.

Damsels and dragons… but no prince

damsel fly at rest, Next-Door Nature, urban wildlife

This lanky damsel isn’t waiting for a charming champion to rescue her (or him?). It’s just resting up for another mosquito-shopping trip (Photo: Tomquah, Creative Commons license).

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Once upon a time there was a damsel(fly).

[Imagine, if you will, a bucolic Disneyesque soundtrack of flutes and piccolos in the background.]

She (Or maybe he. This is a modern fairly tale.) explored the lovely little pond from which s/he had recently emerged after having spent most of life underwater as a nymph.

Who would have guessed during that awkward adolescence, when growth spurts had him/her literally jumping out of her skin a dozen times or so, that she would transform from an ugly duckling into a swan? (Speaking of awkward… let’s just stick with “her” from here on out for the sake of simplicity, shall we?)

So… today was her debut. A coming out, of sorts, and the damsel(fly) flitted here and there, enjoying the warm sun shimmering and gleaming on her iridescent wings as she dipped down to the water now and again to daintily snack on mosquito larvae.

Not a care in the world.  Completely oblivious to…  [Cue the ominous bassoon music] …the looming presence of a dragon(fly) on the other shore.

Not that it mattered, really. [Can I have the flutes and piccolos back, please?]  Sure, the dragon(fly) was part of the Epiprocta clan, the damsel(fly) a Zygoptera, but they were both members of the Order Odonata. No family feuds that she knew of, and so closely related were they that many folks had trouble telling one from the other without assistance in the form of a handy reference table.

They were cousins, but not kissing cousins. No interspecies hanky-panky here, even though their kind were known as having an unusual approach to romance. You see, instead of offering a wake-up kiss, the male clasps the female behind her head with a special appendage on the tip of his abdomen. IF she welcomes the embrace, instead of sliding her foot into a size 6 glass Louboutin slipper eventually she loops her abdomen forward to pick up the spermatophore from a structure on his abdomen and deliver it to her spermatheca [Latin is a romance language, remember].

I know, I know… it sounds kind of weird and kinky but trust me, it’s just hard to describe. When it’s right it’s a beautiful thing, especially when the couple forms a kind of heart with their entwined bodies [Everyone say “awwwww”].

Sometimes they even become members of the Mile-High Club, flying united for a little while. But damsel(flies) and dragon(flies) aren’t the marrying kind. They’re independent and self-sufficient—a characteristic that begins in infancy. Good thing, too, because, to be perfectly honest, the adults are neglectful parents. Dad is no prince, zooming off with hardly a backward glance at the new Mom-to-be, who’s no queen of the nursery herself. She deposits her eggs in floating plants or directly into the water and then washes her (metaphorical) hands of the responsibilities of child-rearing.

The nymphs (aka naiads) hatch and, being carnivorous little monsters, begin feeding on mosquito larvae, daphnia, tadpoles, small fish, and sometimes each other.

That happens among adults as well, although the jury’s still out on the subject of postcoital cannibalism, a not-uncommon behavior in the insect world. It’s enough to give a girl pause (although, for most insect species it’s the guy who needs to worry about fatal attractions).

Whatever. This is the 21st century and females of every stripe and species are all about DIY.  Gals today don’t need a prince to save them. Locked up in a tower? Any modern, self-respecting damsel knows you simply pull out your smartphone, Google instructions for making a rope out of sheets, and then shimmy down to freedom.

Evil stepmother? Please. Dial the Child Abuse Hotline and tell that witch you’ll see her in court!

Face to face with a dragon? Reach for your trusty catch-pole or tranquilizer dart gun apps.

And live happily ever after.

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© 2012 Next-Door Nature—no reprints without written permission from the author (I’d love for you to share my work; all you have to do is ask). Thanks to these photographers for making their work available through a Creative Commons license: [starting from the top]: Tomquah (cover damselfly); Photo munki (nymph… not the same species); Clifton Beard (mating damselflies); Ben McLeod (dragonfly eyes); and Charles Lam (damselfly eyes).