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Commentaries, otherwise unpublished

Firebugs - a fire triangle


     Melanophila is a genus of beetles that, enabled by infrared-sensing organs and antenna sensitive to smoke, seek out fire.  They are not just drawn to fire the way a moth is to light, or bison to the regrowth after a burn, but as a requirement of reproduction. Flame, heat, and smoke attract males; the females lay eggs in burned stumps or beneath scorched bark; the freshly birthed larvae feast on burned wood.  The Melanophila are, literally, firebugs.

      The type beetle was identified in 1774; some 15 species are now known.  They are critically depend on fire, without which they will expire.  With it, they reproduce offspring into an ideal environment rich in their preferred food and largely free of competitors.  Reports exist of beetles finding fire up to 80 miles away.  They are, in a sense, fire foragers in a positive feedback. The more fire, the more beetles.

      As pyrophiles, the beetles are not unique. Thirty times more insects are known to display pyrophilic traits through behavior that draws them to fire and smoke, specific adaptations that promote such attractions, or significantly greater abundance in burned sites relative to unburned sites.  Probably 54 species have what is regarded as the most diagnostic feature, sensors that target heat and smoke, a preference for fungi that grow on burned wood, or as with Melanophila a reproduction cycle that relies on fire ('reproductive synchronicity'). Fire is a shape-shifter, synthesizing its surroundings; its associated insects reflect that diversity.

      The beetles are only a smattering of species, both plant and animal, that accommodate fire or, as with Melanophila, depend on fire to survive.  Many birds, mammals, reptiles, and invertebrates seek out recently burned landscapes, where they scavenge amid the ash and feast on the lush regrowth that sprouts afterwards.  Even flaming fronts can attract predators.  In Australian savannas the flames flush out small marsupials, lizards, and insects that are hunted by carnivores and insectivorous birds; above them all soar wedge-tailed eagles, kites, and falcons looking for prey.  Black kites, whistling kites, and brown falcons have even been seen to pick up smoldering branches and deposit them elsewhere, thus enlarging the hunting grounds (National Geographic, 2018). 

      Fire spreading is a talent the firebugs lack.  It isn't clear how intentional the firehawks are, and they can't start and stop fires, or nurture and pass along a fire culture.  But their capacity to transport firebrands moves the gamut of fire accommodations from passive to active, from adjusting to fire's presence to anticipating, requiring, and perhaps promoting it to encourage conditions that a creature wants. It's a spectrum of fire relationships that ends most densely with humans.  Like fire beetles they search out fires and burned sites; unlike any other creature, even the fire hawks, they can start and within limits start fires at will.  Their firepower allows them to hack into the operating system of whole ecosystems. 

      Here is where they differ from Melanophila and all the other fire accommodators and promoters on Earth.  The fire beetles are opportunists, relying on outside conditions to furnish fires.  Humans create opportunities by determining the place and timing of fires.  Its unrivaled firepower has left humanity as the keystone species for fire on Earth.  People themselves have long seen their capacity to manipulate fire as a defining trait – over and over, fire origin myths describe humans as weaklings until they get fire, at which point they become the biosphere's superpower.

      Thanks to cooking, humanity's dependence on fire is coded in its genome.  Then we went from cooking food to cooking landscapes for hunting, farming, herding, foraging, even fishing.  It's as though Melanophila could control the fires on which it depends, all the while reshaping the environment within which those fires occur.  "Niche construction" is jargon for saying that organisms manipulate their surroundings to support their needs.  Humanity's firepower has allowed it to reshape the planet.  We went from cooking meat and tubers to cooking Earth.

      Since the end of the last glaciation, humanity's fire practices have, with nudges, reorganized aspects of the Earth System.  The epoch of unbounded burning, however, has shoved the planet out of its 2.6 million years of serial ice ages and into a fire age.  A fire creature went global: humanity created a world powered by and pushed toward a world of more fire.

      Still, there were limits.  Fire had co-evolved with terrestrial landscapes and was bounded by their ecological baffles and barriers.  Those borders were elastic, and people could shift them within limits.  But when that quest fire moved from burning living landscapes to lithic landscapes in the form of coal, gas, and oil, those old fetters were smashed.  Prometheus shed his shackles.  Air, water, and land began overloading with the effluent of this novel combustion, a variety of burning for which humans were the essential agent. 

      Inevitably, fire beetles and fire hominins met.  More and more, people were responsible for planetary pyrogeography, which meant the habitats of Melanophila.  The pivot to lithic landscapes as a source of primary power, and the appeal to this firepower, to replace the ecological tasks previously done by flame unhinged the real of the beetles as it did climate.  In developed countries fewer fires occurred, and too many of those that did ignite did not do so within the regimens that fire beetles needed.  Melanophila found its habitat shrinking.

      Interactions between the two versions of firebugs, much like fire, run a gamut.  Some are harmless, like swarms of beetles annoying firefighters.  Some were comical, like the episode (perhaps anecdotal) in the 1940s  during a football game at the University of California-Berkeley in which so much cigarette smoke enveloped the stadium that it attracted enough Melanophila to plague the fans.  A few were serious.  To maintain FSC certification, Sweden enacted legislation that required a fraction of the slash left from logged forest to be burned to assure the beetle's survival (Berndt, 1991).

      It all seems a straight-forward retelling of another morality tale from the Anthropocene, with quirkier characters and perhaps greater illumination.  But there is another, complicating party in this menage a trois.  Fire.



      Since the Enlightenment, fire has been what Western science says it is, and since the discovery of oxygen in the late 18th century, Western science has defined fire as a chemical reaction shaped by its physical surroundings.  It's a physical process that can be fashioned into tools and housed in special chambers to produce power.  Something that had always existed in landscapes, loosely governed by biotas, wind, drought, terrain, was now deconstructed into combustion, each of whose components could be isolated and enhanced and the product monetized.  What had free-ranged as an ecological presence now resembled a factory chicken.  What had likely been our first domestication had the life literally taken out of it.

      But while combustion can be dismantled and reassembled in a lab or factory, and its effects replaced by other sources of raw power and its biological role supplanted by petrochemicals and machines, fire can't be abstracted from its habitat in living landscapes.  It's not a thing, not a substance, not an element.  It is a reaction that takes its character from its context, that in many respects resembles a creature. That resemblance is not limited to poetry and painting. 

      Though not itself alive by the definitions of modern science, it is a creation of the living world that takes on the properties of life and depends on that living matrix to breed and propagate. Life created the oxygen and fuels fire requires and in the form of humanity life provides most of its ignitions.  Its chemistry is a biochemistry: it takes apart what photosynthesis puts together.  It breathes, it feeds, it moves; it undergoes a life cycle, from a spark of birth to cool-ash death. It spreads by contagion.  Like a virus, an "infectious agent," not technically an organism, it takes on the properties of one when it (as it were) comes to life.

      Like other creatures fire shapes its surroundings, not only in what burns but as a selective force in evolution to modify those fuels to encourage or discourage more fire. Unlike other examples of faunal niche construction, fire propagates and involves everything it touches.  The end result is almost always to make the landscape more fire-prone.  Loren Eiseley famously likened humanity to a flame, consuming and remaking into something like its own image those landscapes it passes through.  Perhaps the reverse is equally apt, that fire resembles humanity, its most venerable ally.  Deep in the Pleistocene the two formed a mutual-assistance pact that has bolstered the range of each.

      In the end, fire may defy metaphors, much as it defies simple definitions or categories.  It changes with each time and place, even as it alters those times and places.  Ice is nature as modernist, fire is nature as post-modernist.  Fire furnishes metaphors, it rarely receives them.  Perhaps it is enough not to define its essence but to know what it does.

      So the story of Melanophila is really a story of three creatures – a fire-adapted beetle, a fire-wielding mammal, and fire, a biologically-based reaction in a nether world neither wholly alive nor wholly dead.  Fire is not a bug in the Earth System: it's a feature.  After all Earth is the unique home for Melanophila, Homo, and fire, which as Henry Thoreau observed, "is the most tolerable third party."


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