My girlfriend is terrified of moths.
She hates them; purely, unabashedly, and completely. She despises their habit of gracelessly barreling out of the dark, smashing into anything and everything (including human faces) in a flurry of fluttering wings. She hates the way they persistently ram themselves into outdoor lights, which oh-so conveniently tend to be right above her head just outside of the front door, cutting her off from the frustratingly close safety of her house. She loathes the angry drumming sound they make when they clumsily bat their wings against whatever wall or window they are crawling across. She shivers at the mention of their wings, which she describes as “dusty” (the powdery coating is actually made up of very tiny scales that cover the wing; butterflies have these as well). I’ve watched her spot a particularly massive, beastly, mothy bastard spread out sinisterly underneath a neighbor’s outside window sill, and immediately swing her path past it into a wide berth, eyes cautiously locked on the insect threat. She does not like them here or there. She does not like them anywhere. My girlfriend does not like the moth. She does not like them, David Lee Roth.
Because of her undeniably real, demonstrably intense dislike of moths, she was not exactly appreciative of the fact that the last week of July (July 19th through July 27th) was National Moth Week (or of the fact that I’m writing this blog post at all, frankly). For those of you that are unfamiliar, National Moth Week, started in 2011, is a global citizen science effort wherein groups of those inclined (called “moth-ers”, but I like to call them “moth-heads”) set out into the night equipped with lights, a white sheet, a bait mixture made of something like rotten fruit, molasses, or beer (preferably not the good shit; stick to domestic swill like Bud or Coors), and perhaps a camera for recording purposes…all of this to observe and categorize whatever moths they find attracted to their lights or bait, and to potentially contribute their findings to a multitude of databases. In this bit of crowdsourcing of data collection, we are able to know a bit more about the distribution of moth species (and for many species, where they turn up in the world is not well-known), and their general abundance over time, which is important to keep track of, considering that moths are good early indicators of decline in an ecosystem’s ecological health. Another major focus of National Moth Week is to bring awareness to moths, which are oftentimes regarded as boring, drab nuisances instead of the diverse, often colorful, interesting animals that they are. NMW also provides an opportunity to get groups of school age children together to not just learn about moths and the natural world that surrounds where they live, but to take part in a globally held citizen science project, hopefully inspiring some of them to take interest in the biological sciences in a more permanent sense.
Truthfully, moths are far more interesting than we give them credit for. They are diverse in form, size, coloration, and behavior. They are unfortunately pegged as dull creatures, which, at their best, are annoying, and at their worst, a pest that destroys clothes and crops. There’s a single thread runs through their popular characterization; one that paints moths as fundamentally benign, like a house fly, or a slug…something to put up with, and nothing to get too excited about; the “white bread” of the insect world. But, while it’s important to remember that moths are interesting by being incredibly important members of their ecological communities, as insatiable, leaf-obliterating larvae, as pollinators of flowering plants, or as nutrition for everything from birds to bats…there are a number of species that solidly destroy the notion that moths are innocuous at the acutely individual level. Some species are downright threatening, blatantly ignoring the memo about how moths are “supposed” to be the awkward, dirty, night shift butterflies of the world and nothing more disconcerting. These species, twisted, creepy, grotesque, and malicious even by arthropod standards, make it difficult for me or anyone else to dismiss my girlfriend’s mottephobia (the fear of moths) as being unfounded.
First, behold Chionarctia nivea, a superficially normal-looking type of icy white “woolly worm” moth that frequents the frigid northern reaches of Russia and East Asia, where, based on the elegant evening wear it has on in the photo below, it apparently flutters around perpetually dressed like Galadriel.
It’s a nice looking moth. Personally, I dig the sleek, streamlined thing it’s got going for it, and the titanium white coat gives it a classy aesthetic. It lives a very mothy life, doing lots of the typical mothy things. There’s nothing observably alarming or offensive about this species, which conveniently disguises itself as a cottonball, which is perhaps the mascot for unblemished innocence. This is a good, clean moth you can trust. This is a moth that pays its taxes, that always drives 5 mph under the speed limit, and has superb credit. This is a moth who you might feel comfortable voting for in the upcoming school board elections, because this moth has integrity, goddamnit, and integrity is hard to find these days.
But the males of this species conceal a disturbing secret…
With a bit of air pressure, the Chionarctia nivea moth deforms its abdomen into an awful assembly of alien French ticklers, unfurling bits of prickly, translucent membrane into the world’s worst precursors to balloon animals.
So, why? Why do the dude moths in this species insist on extruding these visually comfortable and vaguely threatening ass tentacles, immediately transforming themselves into something that looks like it would terrorize Kurt Russell in an Antarctic research station? And what do these organs do?
If you are asking yourself if the male-specific, extendable, phallic appendages are “a sex thing” then your suspicions are correct. These are totally a sex thing. But these love balloons ain’t for the actual moth hanky-panky. They are instead used in the initial wooing of females of the species. These organs (called “coremata”, and are found in lepidopterans (group of insects that includes moths and butterflies) in general) are lined with bristly structures called “hair-pencils”…and these hair-pencils write the language of sweet, sweet, moth-y love.
Well, to be more specific, they release a cocktail of pheromones that advertise to the female moths that the owner of those sexy coremata is a choice mate. When a male moth gets wind of far-spreading female pheromones, he tracks her down, and once close enough, he puffs up those fuzzy butt feelers like a pair of inflatable, advertisement airdancers and lets loose his intoxicating cologne. If the lovely lady is satisfied by what her antennae are picking up, the two love bugs can commence with the bumpin’ of abdomens.
The hair-pencil pheromones also appear to have a repellent effect on other males of the species. Once the stank of another bro moth’s sex solicitation juices are mucking up the air somewhere, it’s a bit of a turn-off to all the other males, apparently.
So, one species’ sickening “I don’t know what it’s doing, but get that fucking thing away from me” is another species’ steamy courtship display.
Alright, you say, so some species of moths have males that are particularly…er…”well-endowed”…with respect to their creepy, pneumatic, romancin’ not-penises. Big deal. It’s not like they are actually doing anything malicious. You are, perhaps understandably, unimpressed with this example of moth malice.
So, I say, consider the following scenario:
It’s a warm, humid night in the outlying, forested areas surrounding Vladivostok, Russia. There’s not much of a breeze tonight running onto shore from the Sea of Japan, and the air is thick. You are sitting out on your porch, drinking a Yarpivo Amber, trying, in vain, to use the night air to cool yourself. The coniferous forest around you is alive with the songs of crickets, and the darkness enveloping you, and the alcohol trickling from your blood and into your brain allow a blanket of relaxation to drape over you. Just before you drift off to sleep, a wayward, winged insect visits your position under the white intensity of your porch light. It’s a nondescript, little brown moth, and it delicately settles all six of its petite feet upon the back of your hand. You’re careful not to move and scare it off as you watch it wander back and forth across your hand, stumbling over the occasional hair, antennae twitching and wings wavering slightly to keep balance. You are instantly calmed by this intimate moment, briefly connecting with nature. An angel of the forest has stopped by and offered you the gift of its presence, and you feel as though the two of you are communicating on some kind of deep, ancient, spiritual level.
Just as a smile begins to illuminate your face, you watch as the moth slowly and deliberately unrolls its long, fragile proboscis…and proceeds to drill the end of it into the skin between your knuckles. Pain and shock jolt you to full, electric alertness as the moth plunges the sharp tip of its tubular tongue into your flesh and greedily laps up your blood like a cat at a water dish.
You’ve just had a run-in with the vampire moth, Calyptra thalictri.
Most adult moths and butterflies are passive nectarivores, and spend their days daintily sipping sugary nectar from wildflowers and flitting about as if their entire lives were an extended, sunny, spring tea party.
But not Calyptra, along with its close relatives in a small subfamily of owlet moths (Noctuidae). These guys, much like the mosquitoes and bedbugs were are more familiar with, are hematophagous, meaning that they feed upon blood. Calyptra is a branch of the moth family tree (native to much of southern Europe, Asia, and sub-Saharan Africa) that has taken a hard, evolutionary turn away from an existence dipping into daisies, and has made a serious of concerning, demented life and dietary decisions that would surely put a smile on the face of Bram Stoker’s corpse. Calyptra moths could give less than two shits about your cute little set of flower boxes outside, and are more interested in bringing pain to your veins.
That “butterfly” that supposedly flaps its wings and sets off a chain of meteorological reactions that culminate in a hurricane generating across the world? Yeah, that evil little bastard responsible for all that chaotic destruction (and by association, that godawful mid-2000s sci-fi thriller with Ashton Kutcher) was most certainly a moth named Calyptra.
Only the males of the vampire moth indulge in the “scarlet nectar,” employing their surprisingly tough, rigid tip of their proboscis to puncture flesh, and unleashing a series of spring-loaded hooks that keep them from dislodging easily…allowing them to drink at their leisure. Calyptra moths tend to target large mammalian herbivores, like buffalo, elephants, and rhinoceroses as reservoirs of blood to stick their Straws of Torment into, but on a few occasions, humans have been…fortunate…to know the moth’s bite (particularly when it’s C. thalictri).
Let me be clear on the differences between being bitten by a vampire moth and being bitten by a mosquito. Female mosquitoes have highly specialized mouthparts molded by evolution into a sleek hypodermic needle, delivering a swift dose of blood-thinning venom after an expertly placed pinprick, followed by a seamless transition into hardly noticeable blood slurping. In contrast, vampire moths are working with a tool that is far better suited for piercing the skin of fruits in the search for sugary juices, than it is for living animal flesh…and this is because, unlike mosquitoes, and despite their name, vampire moths are not purists when it comes to the sanguinary dining thing. Male vampire moths are “facultative” blood feeders, meaning that, to them, blood is a “sometimes food”, and their diet is also rich in the happy, normal, not-you-or-me regions of the food pyramid. Calyptra and closely related moths are known for their ability to use their burly proboscises to tear into fruit for sustenance…obviously in rabid, vindictive frustration from getting to the flower weeks too late for nectar. This tool, wonderfully useful in giving a plum the worst day of its life, is woefully unsophisticated (compared to the mosquito’s instrument) when applied to big, ambulatory critters with touchy, inconvenient things like nervous systems.
The difference between getting bit by a mosquito and getting bit by a vampire moth is like the difference between having your blood drawn by a phlebotomist with a quarter-century of training and experience, or by Kevin, the disheveled tweaker with the “can-do” attitude secretly squatting in your neighbor’s shed. The mosquito gets the job done relatively painlessly and quickly with incomparable surgical precision. The vampire moth, on the other hand, opts for enthusiastically digging around in your forearm with a rusty lawn dart.
So, vampire moth bites are crude and painful for their entire duration because, unlike mosquitoes, these creatures don’t make their living from blood. There’s not as much reason to keep you or any other source of blood unaware of their feeding, and their craft is not honed or specialized. This is also part of the reason why these moths don’t pose any threat to people by way of disease transmission; the frequency of biting is too low and the feeding system is too inefficient. The frequency of hematophagy varies fairly widely among vampire moths, as well as the capacity to dig into fruits, with species capable of exploiting fruits along certain sections of a gradient of fruit skin thickness and hardness.
Inferences based on genetic studies of evolutionary relatedness among the group, seems to indicate that the evolution of the behavior doesn’t follow a pattern of supplantation of more primitive, vegetarian feeding modes (nectar, soft-skinned fruits) with more derived ones (hard fruits, blood), but rather that more recently evolved vampire moths simply have more of the feeding strategies available to them. More primitive moths in the group might only be able to probe squishy fruits, but moths like C. thalictri can have it all; thin-skinned fruits, thick-skinned fruits, fruits with a tough rind, people…you name it.
But why all the drama and gore either way? Why has Calyptra developed this propensity to temporarily ditch soft drinks, go full-on fucking Dracula, and cut straight to the hard shit? Flowers and fruit seem good enough for the rest of the moth and butterfly clan, so why does the vampire moth have such a needy palate?
Well, the reason may result from the practice of “mud-puddling”, which is an activity that involves far more bugs and far less mud-wrestling sexy times than you’d think (don’t lie, I know you were imagining it). If you’ve ever seen a bunch of butterflies very obviously touch down next to a shallow pool or puddle and gather around the muddy water’s edge like wildebeest at a watering hole, then you’ve seen mud-puddling. It’s very common among butterflies and moths, and the goal of mud-puddling is to suck up nutrients and salts found in things like mud, dung, and occasionally decaying matter (plant or animal). Mud-puddling tends to be a male-only hobby, and it’s thought that acquiring all these extra goodies has a key role in reproductive success. Males are often observed “gifting” females with these nutrients and salts alongside their sperm contribution. It’s essentially a ridiculously late, coitus-adjacent means of presenting a girl with flowers.
The extra nutritive boost can be of great value to any upcoming larvae to originate from such a pairing, since many caterpillar species feed on plants that are sparse in nutrients.
It is likely that blood-feeding, rather than serving as a food source for the adult male moths, provides another advantageous avenue for aspiring, prospective dad Calyptra to provide his progeny with health and vitality, as blood is literally piped around animal bodies as a nutrient, mineral, sugar, and amino acid smoothie.
Oh, and if you are currently residing in latitudes to the north of the temperate and tropical latitudes of Afro-Eurasia, and smugly reading this and acknowledging your comfortable space far outside the reach of the vampire moth…listen up.
Calyptra has been found, in recent years, to be expanding its range poleward into northern Europe, turning up in places like Finland, which is a place normally considered too cold for these bitey assholes. It’s very likely this invasion is due to recent, rapid, human-driven climate change effects, and that their residency in the north will become not only more extensive, but permanent. I’m relatively certain “influx of fucking blood-sucking moths” is some sort of karmic punishment for what humankind is currently doing to the polar bear.
“Alright,” you concede, “moths can be a little intimidating and off-putting. But not caterpillars! Those younger, squishier, tube-shaped versions of moths are just doofy, derpy, compulsively overeating herbivores! The adorable little buggers couldn’t be a threat to anything if they tried!”
To illustrate just how wrong that is, allow me to take your mind’s eye out into the middle of the Pacific Ocean, to the tropical archipelago where I make my home; Hawai’i. Hawai’i is celebrated the world over for its jaw-dropping natural beauty, with imposing, steep, eroded mountains covered in lush vegetation dropping dramatically down to idyllic white sand beaches. It’s touted as “paradise”, and after living here for a year and experiencing not a single day below 60 degrees Fahrenheit, and the freedom to snorkel along coral reefs and hike in gorgeous tropical rainforest year-round, I can definitely agree with the common, mythic conceptualization of the island chain.
In addition to being so eye-wateringly beautiful, Hawai’i is a remarkable laboratory of evolution, given its location thousands of miles from the nearest landmasses. A large proportion of the land organisms found in the islands are “endemic”, meaning that they are found nowhere else in the world, having evolved in complete geographic isolation from relatives on the mainlands of Asia and the Americas. They range from brilliantly-colored forest birds like the ‘i’iwi, to hardy plants found only along the slopes of volcanoes like the silverswords and greenswords, to a unique subspecies of bat. In keeping with the paradise aesthetic, most of what has evolved out here in the middle of the ocean isn’t much of a threat to jack shit, and especially not to invasive species brought in by human colonizers, which have, depressingly, turned Hawai’i into a laboratory of extinction in addition to one of evolution. With a dearth of many natural predators, whatever lineages were able to make it out here and spread across the islands often let down their defenses after millions of years of vacation. Just ask the moa-nalo, a group of geese-like birds that discarded their ability of flight. They suddenly, and curiously, dropped off the face of the Earth immediately after Polynesian settlers first arrived in the archipelago…it’s almost as if they were easy pickings for food. Weird how that works.
So yeah, a lot of the wildlife in Hawai’i are steeped in their own sickeningly sweet levels of isolation-driven innocence and vulernability. I mean, hell, even the spiders here have permanent happy faces plastered on their chipper selves.
This is not a place where you’d expect to find carnivorous goddamned caterpillars, but that is exactly what Hawai’i has to offer.
The caterpillars belong to moths of the genus Eupithecia, which are a highly speciose, diverse group of small, drab, nondescript moths also known collectively as “pugs.” They are found all over the world, and the vast majority of the time, their caterpillars are conventional, adorable, inchworm-like things, doodling around and munching on flowers and leaves and generally being about as terrifying as a clump of pocket lint.
But there a number of species in Hawai’i that have evolved into skilled ambush predators, lashing out at unsuspecting insects like a demonic spaghetti noodle and clasping them in spiny claws, turning their elongated bodies into a ravenous grappling hook, with all the merciless, direct brutality of a Mortal Kombat finishing move.
Good lord, is nothing sacred in this world? The last time I checked, the Very Hungry Caterpillar ate a lot of shit, but the still-beating heart of a fresh kill wasn’t on the menu.
Hawaiian Eupithecia caterpillars are a product of that evolutionary laboratory I was talking about. The other side of island critters no longer needing anti-predator defenses is the precarious ecological hole left by, you guessed it, no predators. The job position for predatory insects was left wide open since things like mantises weren’t able to survive the extreme distances out to the islands…and these caterpillars have eagerly filled it.
These little grubs of destruction have evolved a simple and effective means of striking fear into everything that flits and buzzes through the rainforests of the archipelago. They, not unlike many of their closest mainland relatives, mimic a small twig, making their gray and brown mottled bodies rigid and still, tightly gripping a branch with their hind feet and keeping the nasty business end erect and ready for action (note to self: Erect and Ready for Action is a great title for a porno). In this position they wait…and wait they do, until some terminally unlucky fly or beetle strays just a little too close. As far as other insects are concerned, the butt end of the caterpillar is just a knobby extension of a branch…and totally not studded with sensitive bristles that instantly alert the head end that dinner has arrived, prompting a lightning fast spasm that brings Mr. Fruit Fly face to face with three pairs of sword-shaped limbs and a glistening battery of sharp, salivating mandibles. Eupithecia arches itself in a tight loop, and like a bullwhip tipped with meat hooks, dispatches its target with deadly speed and accuracy…like a wormy falcon snatching a sparrow out of the air with its talons. The hapless insect doesn’t even have a chance to react, its life is pathetically brought to an abrupt end by the world’s most murderous larva.
It’s possible that there are a number of traits already a part of pug moth caterpillar biology that may have served as “pre-adaptations” to a predatory lifestyle, and made transitioning from passive vegetarianism into being the most malicious maggots in town particularly easy. Their characteristic paroxysmal attack method might have its evolutionary origins in a defensive snapping behavior, in which an attacking bird or lizard might be stunned by the quick movements just long enough for the caterpillar to flop down to safety. This behavior could have been co-opted into their hunting technique quite effectively.The evolutionary transition to an insect-based diet might have been eased by Eupithecia’s tendency to consume specific parts of plants, like flowers along with their protein-rich pollen. A diet already pre-adapted to consisting of high-protein foods may have made switching from salad to steak easier than it would for many other vegan creepy-crawlies.
“Ok,” you start, “Hawai’i’s got some pretty homicidal moth babies. It’s a good thing I’m not a bug, or then I’d have something to worry about. Luckily, there’s no caterpillar that could possibly impact my health or well-being.”
Yeah, no. Not even fucking close.
Meet Lonomia, a genus of moths found in South America that are closely related to the stunningly patterned and gigantic atlas and luna moths. However, the adult Lonomia moths are far more conservative in coloration than their more famous family members, choosing to go with subtle camouflage against the backdrop of their woodland home. This is not an unusual strategy among moths.
Lonomia caterpillars are also gifted with the ability to blend in, but are covered in short, pale, spiky clusters of hairy projections, thus disguising themselves instead as diminutive Guy Fieris, sent to Brazil to film a special episode of “Diners, Drive-Ins, and Dives.”
“So, that’s it? That’s the big bad caterpillar? Why, I can crush that fuzzy mulch-muncher into a moist smear on the bottom of my boot with no problems whatsoever.”
Yes, but you’d better make sure it’s a boot, and you’d better make sure you throw that boot away when you’re done, making damn sure you don’t touch the bottom of it without thick-ass gloves on.
Lonomia caterpillars’ hazard doesn’t lie in a predatory inclination, or an unpleasant bite like that of the vampire moth. Lonomia is dangerous because of the thick forest of branched spines (called “scoli”) which harbor hollow bristles, each one loaded with its own lovely little dose of venom. These types of defensive hairy structures are common in many types of caterpillar, and many people can get unpleasant and painful skin reactions from touching them and becoming envenomated. But Lonomia‘s special blend of toxins is so devastatingly potent that interactions with this caterpillar, like simply brushing up against it, has lead to human deaths. Yes, this is a caterpillar that can kill you fucking dead.
All species in this genus are highly venomous, but one species in particular, Lonomia obliqua, holds the “honor” of bringing forth the highest frequencies of severe reactions to the venom. Not everyone who accidentally collides with these cryptic caterpillars when moving through the forest (as is typically the way in which the envenomation occurs; when hands and forearms are clearing away brush and inadvertently smack into a feeding Lonomia), but the mechanism by which these perilous pincushions deliver their venom and how this venom does its dark deed remain the same:
The venom is produced within hair-like structures, called “setae”, situated on the scoli. Unlike many other venomous animals, which have a single, definable “venom gland” that secretes and stores the venom, Lonomia, instead, has an array of microscopic vesicles (little sacs) embedded within the cells making up the inside layers of a hollow, tubular tract inside of these bristles. The diabolical cocktail of toxins is slowly secreted from these cells, and pool in this cavity at the base of the tip of the seta. And there it sits. Waiting.
The tip of the bristle, hard and chitinous, is fashioned in such a way that there is a “weak spot”, a pinched line of fragility, near where this internal venom reservoir sits, such that upon just the slightest irritation (like a hand coming along and embedding the toxic needles within the skin), it breaks off like a glass ampule.
The tip busts open like a champagne bottle, releasing a lovely, effervescent torrent of horrific toxins right into the bloodstream of whatever poor soul owns that ill-fated hand.
Initially, the stinging sensation from the wound is hardly noticeable, and certainly not something you’d feel the need to stop and inspect what happened, especially if this happened right in the middle of vigorous, sweaty outdoor work. So when the true effects of a particularly bad envenomation start to take place in the coming hours and days following contact with the caterpillar, it may come as an unwelcome surprise to the victim, who may not actually remember getting bit or stung by anything at all.
And what exactly are these effects? Lonomia has a venom with amazingly strong anti-coagulant and anti-fibrolytic properties…meaning that it stops your blood from doing that fairly important function of clotting. If you are unfortunate enough to get a high enough dosage of venom, your blood not only ceases to clot, but your entire circulatory starts…well…leaking. As you might have guessed, when all your internal plumbing suddenly begins to drip like a loose sink pipe, that can be a huge goddamn problem. Envenomated folks can often present with a “hemorrhagic syndrome” called lonomiasis, which most commonly results in widespread bruising in places where your blood is pooling out of your toxin-ravaged circulatory system, making you look like you got worked over real good by an army of angry people with crowbars and bats. All of this happens in nearly complete silence, generally undetectable to the victim in the period of time following the sting. If you are pricked, a great deal of time can pass in complete ignorance of the growing, gushing, collective fount of internal bleeding caused by the venom, causing your organs to marinate in this flood of what should be oxygen-rich juices, disastrously re-routed away from their crucial role in keeping you alive.
In the most extreme cases, this can snowball into brain hemorrhages or renal failure, which of course can precipitate death from catastrophic brain and kidney damage.
Death by caterpillar is not the preferred way to exit this life.
Luckily, about only 2% of those suffering from such Lonomia-related accidents actually perish. Also, on the bright side, the stupendously potent anti-coagulant properties of the toxins found in Lonomia venom have potential medical applications, specifically in the treatment of maladies in which too much clotting is a problem. So, despite the undoubtedly real dangers posed by this moth’s childhood phase, Lonomia might eventually end up indirectly saving far more lives than it has ended.
Moths are fantastic animals, and live far more interesting and dynamic lives than we tend to acknowledge. Whether it’s the unsettling sex-balloons of Chionarctia, the barbaric bite of the vampire moth, the rapacious tyranny of Hawai’i’s most vicious caterpillar, or an insect armed with one of the deadliest touches on Earth, it’s abundantly clear that some moths also certainly possess a unexpected capacity for horror, and command a nervous respect from humankind that they rarely receive.
Image credits: Introductory moth image, Chionarctia nivea, vampire moth, “cute” caterpillar image, Lonomia adult, Lonomia caterpillar, carnivorous caterpillar gifs originally from footage from this BBC Two clip
© Jacob Buehler and “Shit You Didn’t Know About Biology”, 2012-2014. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Jacob Buehler and “Shit You Didn’t Know About Biology” with appropriate and specific direction to the original content.