Looking for even more Next-Door Nature? Check out my guest post on the Center for Humans & Nature blog:
[I’m working on a number of new posts for the coming weeks, and to provide myself with some breathing room today’s post is a reprint from July 14, 2015… Enjoy!]
The bees of Whitecross Street, London, UK, in honor of the beleaguered pollinators upon which we depend far more than most people realize [Photo: duncan c, ccl].
© 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.
[you might need to boost the volume a bit on this one]
© 2015 Next-Door Nature—no reprints without written permission from the author (I’d love for you to share my work but please ask). Thanks to these photographers for making their work available through a Creative Commons license (CCL) or Project Guttenberg License (PGL) (from top to bottom): USFWSmidwest (eastern gray treefrog); Jimmy Smith (field cricket); Lisa Brown (common true katydid); Rachid H (common meadow katydid); Roger Engberg (dog-day cicada); Andy Reago & Chrissy McClarren (northern cricket frog); AllieKF (American toad); Matt Reinbold (green frog); J. N. Stuart (boreal chorus frog); USFWSmidwest (eastern gray treefrog).
Kindergarteners swarmed around the khaki-clad naturalist, squealing with excitement, shouting out questions and jockeying for a better view. The adult volunteers on this field trip were a tougher audience.
“I’m glad they’re having fun but I don’t see why anyone should care about some bug,” one 30-something mom confided to another, adding, “What good is it, anyway?”
I overheard this question while visiting a nearby urban nature center but it’s just one variation on a theme I’ve heard throughout my life and career… a theme that opens the door to fascinating explorations of the ways human beings assign instrumental and intrinsic value to creatures great and small. And I do so love engaging philosophical conversations.
My first, unfiltered instinct, however, is to hurl the question back at them like a boomerang: “What good are YOU?”
I catch myself—usually—before the words escape, gently reminding my outraged inner eco-warrior that choosing honey over vinegar improves our chances of winning both the battle and the war.
To successfully implement a honey-offensive, it helps to have an arsenal of sweet scientific research think-bombs at the ready. This is an arms race and, naturally, I’m always on the lookout for a chance to acquire the hottest new technology so I can blast misconceptions and prejudices to smithereens.
Imagine, if you will, my greedy glee when, last week, I stumbled on an amazing new trove of ammunition from a most unlikely source.
Is there a creature more likely to inspire the value question than a cicada? (In those parts of the world where insects are not a significant source of protein in the human diet, that is.) How’s this for a life cycle? Hatch from your egg, drop out of your natal tree, dig in and spend 1—17 years (depending on your species) hanging out underground sipping root juice and metamorphosing through various awkward stages of puberty. Finally emerge from the soil, climb out of your skin one last time. Rest until your shiny new wings harden then hook up with a member of the opposite sex and get busy… or not. Depends on how long you can avoid being eaten by a squirrel, a bird, a dog or cat, a fish… and rest assured, you will be eaten at some point during those 1—6 weeks of halcyon summer days preceding your demise. Unless you are transformed into a zombie slave by a cicada killer wasp (Exeirus lateritius) in need of a surrogate mother for its offspring, in which case you’ll still be eaten but it will take longer for you to die.
One could argue that if the nihilists are searching for a mascot, they need look no further than one of the 2,500 Cicadidae clan member species. Still, until the pointlessness of existence becomes a dominant meme in human culture even a potential poster-child gig is unlikely to satisfy a determined anthropocentrist who insists on asking, “What good is it? You know… for people?”
Turns out, Australia’s clanger cicada (Psaltoda claripennis, aka clear wing cicada) may end up doing quite a lot of good for people. Unintentionally, of course; insects aren’t known for their benevolence. But according to a recently published Biophysical Journal article cicadas may be an accidental ally in our battle against bacteria.
Chemical warfare is common in the insect world. Humans readily adopt the same strategy against both microscopic and macroscopic opponents (although, in most circles it’s considered verboten in human-versus-human conflicts). Funny thing about man-made poisons—they tend to deliver short-term success followed by long-term environmental headaches, especially when used against enemies with high reproduction rates. Insects and bacteria, for example. As a former defense secretary once said, though, you go to war with the army you have. We have chemicals. Lots of chemicals.
How refreshing, then, that according to a team of researchers from Australia and Spain, evolution has armed the clanger cicada with a vaguely medieval yet elegantly simple physical defense against infection.
Enough to make a punk rocker proud (and Vlad the Impaler SO jealous). You see, clanger wings are covered in an array of sharply pointed nanopillars. When a hapless bacterium settles on this surface, it stretches and sags into the crevices between the spikes, like Jell-O on a bed of nails, until the cell membranes are shredded and the microbe is incapable of reproducing.
Scientists have already begun to investigate the potential of synthetic cicada-inspired materials. Think of it—in the not-too-distant future countertops, doorknobs, bus straps and subway poles, sinks and commodes, railings, surgical instruments and even money could be covered with a passive bacteria-killing surface that makes the ubiquitous hand-sanitizers obsolete!
Now, how could an invention like that possibly do a young mother any good?
© 2013 Next-Door Nature—no reprints without written permission from the author (I’d love for you to share my work. Just ask first.). Thanks to these photographers for making their work available through a Creative Commons license: OakleyOriginals (smiling face, 2008); Pholra (kitten, 2007); Steven Krichten (cicada killing wasp, 2003); Melanie Cook (clapper cicada, 2004)
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).
Temperatures across the southern half of the U.S. are soaring into triple digits, so I was trying to think of creative solutions to beat the heat when it hit me—why not become cold-blooded!
Alas, my brain must have overheated. Once air conditioning allowed a cooler head to prevail I realized that what seemed like a brilliant idea while baking beneath a blazing sun is absolutely, completely, utterly impossible… and not simply because mammals cannot will themselves to undergo metamorphosis.
You see, technically there’s no such thing as a cold-blooded animal (unless you’re speaking metaphorically about someone who lacks emotion or empathy). Or a warm-blooded animal, for that matter. Both terms are shorthand for the ways in which body temperature (aka thermophysiology) is controlled in different types of organisms.
Most mammals and birds are classified as endotherms (Greek: endon = within; thermē = heat). For these critters thermoregulation is an inside job, primarily by way of metabolic processes. Under extreme environmental conditions some physical mechanisms come into play, but not solar energy (at least, not directly). If the mercury plummets and the body’s core temperature begins to drop, muscles shiver to create warmth; if the core temperature starts to rise the body perspires to cool via evaporation. No sweat glands? Pant like a dog… or birds. All evidence to the contrary, since humans are mammals, swimsuit-clad sunbathers dozing in rows on a beach or poolside with icy drinks standing at the ready are, in fact, capable of maintaining a relatively constant body temperature.
When an animal’s body temperature is strongly influenced by ambient conditions it’s an ectotherm (Greek: ektós = outside). Fish, amphibians, reptiles, and invertebrates rely on external heat sources to get their juices flowing, especially during the chillier seasons or cooler times of day. That’s why these animals can be seen basking on rocks, roads, and any other warmth-radiating surface. Then, when they can’t stand the heat they get out of the kitchen, retreating into shade, water, or underground to cool off (Sound familiar? We really are more alike than different).
Take-home message: mammals and birds are endotherms; invertebrates, fish, amphibians, and reptiles are ectotherms.
Except when they aren’t.
It’s the exceptions that make the rule, right? Let’s begin with the usual ectotherm suspects. According to one source, 2% of invertebrates are endothermic. Regrettably, the informant failed to name names but, in spite of the fact that spineless animals are not my strong suit, I did managed to chased one down—snails and slugs (Oops, that’s two… and “chased” may be overstating things). Fish, being vertebrate species, are my regular beat so I can state with certainty that billfish (e.g., sailfish, marlins), tuna (Scombridae), one family of sharks (Lamnidae, including makos and whites), and one species of mackerel (Gasterochisma melampus) are endothermic… at least to some degree. I’ve yet to find a reliable report of an endothermic amphibian, but among the reptiles sea turtles exhibit both ecto- and endothermic traits.
Moving along to the endothermic exceptions… Hummingbirds (Trochilidae), swifts (Apodidae), and common poorwills (Phalaenoptilus nuttallii) all experience periods of lower body temperature and metabolic rate; therefore, some biologists argue they have ectothermic traits. Additionally, there are mammals—certain rodents, a couple of lemurs, and many bats—that enter hibernation or estivation in response to low temperatures or drought, respectively. Then there’s the echnidna (Tachyglossidae), a “primitive” mammal from Australia that’s an ectotherm eleven months of the year and an endotherm during the month when it lays its eggs (Yes, eggs. If you like rule-breakers Australia is your Mecca. In the interest of time and space, though, we’ll have to save monotremes for another day).
What I’ve presented above is a fairly simplistic description of thermophysiology. Why stop there? Because a more thorough treatment would require a good deal of nuance and a complicated discussion of sub-categories, not to mention a stiff drink (the current temperature is 99°F and rising—make mine a frozen margarita). But since it’s so hot I’ll go ahead and venture past a toe in the water… up to my knees, but no further.
One subset of the endotherms are tachymetabolic (Greek: tachy = quick), organisms with a consistent and extremely high metabolic rate. Shrews (Soricidae) are a perfect example—diminutive beings with massive appetites, their metabolic rate is at least five times that of similarly sized ectotherms. Being able to snack non-stop and still rock a bikini probably sounds too good to be true. It is. Finding a constant supply of calories without access to fast food and grocery stores is no picnic. Bradymetabolic (Greek: brady = slow), which could easily be mistaken for bipolar disorder, is no bed of roses either. These organisms swing wildly between a high (when active) and low (when resting) metabolism, usually based on either external temperatures or food availability. (If you think someone else has got it better, rest assured you probably don’t know the whole story.)
As biologists refine our understanding of how bodies work, language evolves and once popular terms like cold-blooded fall from favor. Popular stereotypes suggest otherwise, but scientists are not completely immune to trends. When I was an undergrad, for example, the preferred word for organisms influenced by changes in ambient temperature was poikilotherm (Greek: poikilo = varied, irregular). Although still useful for making distinctions between types of ecotherms, the term is used less frequently now and may be on it the way out.
C’est la vie. Styles change, in both the lab and on the beach (Thankfully. I’m old enough to remember when Speedos were all the rage in men’s swimwear). I’d be willing to bet, though, that most Earthlings won’t give up sun worship any time soon. Chillin’ in a sunbeam feels too good, whether you need it or not (at least as long as there’s a pool nearby).