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  And with that comes a question entomologists are solving in a multitude of ways: what contributes to that learned behavior? To get a good handle on all things innate, and the basic mechanics of bug existence and survival, scientists dust off their microscopes and Freudian chaise longues to discover the driving psychological and physical forces of an insect.

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  One of my favorite questions from the book Do Bees Sneeze? is from a third-grade student in Oyster Bay, New York: “Why do flies’ eyes look like boom box speakers?”

  An apt and cute comparison. Unlike our single vision, some insects have multifaceted lenses. Compound eyes are one of the first bug components that captured our attention. Seventeenth-century scientist Antonie van Leeuwenhoek was the first to view an insect eye’s optical array. He wrote in a letter to the Royal Society of London: “What I observed looking into the microscope were the inverted images of the [candle’s] burning flame: not one image, but some hundred images. As small as they were, I could see them moving.” Two hundred years later, another scientist wrote: “The best of the eyes would give a picture about as good as if executed in rather coarse wool-work and viewed at a distance of a foot.” Not much of a view.

  With eyes like that, a Van Gogh may not cause the same visual arrest as it does in us. Objects don’t register too well for bugs. And though bugs possess trichromatic color vision, they tend to see only shorter wavelengths. But insects’ compound eyes, besides giving a panoramic view, allow them to register, say, the speed of a fly swatter much faster than mammals.

  Chemically sensitive cells “housed” inside their bodies govern the majority of an insect’s taste, smell, and touch. These chemoreceptors may even lie in their legs. The antennae, significant sensory organs for touch and smell, can also be used as airspeed indicators and to detect sound vibrations. Detecting the outside environment? That’s due to the mechanoreceptors attached beneath the hairs on their exoskeleton. The hairs also aid in physical orientation.

  In addition to Van Gogh, you’ll have to scratch Beethoven off the list of bug pleasures. The majority of insects are tone-deaf. Their eardrums, the thickness of which ranges from 1 to 100 microns (the average thickness of human hair), can receive vast frequency bandwidths to, in part, recognize mating calls and assist in echolocating holla back replies.

  Other questions in Do Bees Sneeze?—an impossibility due to a lack of sinuses—address plenty of things you may have wondered yourself. Chief brain tickler among my friends, at least drunkenly, was in regard to insects’ pain and emotions. How much do they feel when they go squish? Is there a certain damnation carved out for malicious children plucking the wings off a fly?

  Bugs lack nociceptors you and I possess—nerve cells that alert us when our discomfort is pushed to the brink. It’s our emotions that then assign “pain.” (Although no conclusive evidence is around, biologists like David Anderson and Ralph Adolphs have shared Darwin’s argument that it’s possible invertebrates have “central emotion states as well.”) The writhing a tortured bug exhibits is a preprogrammed response to survive. As in all creatures, reflex governs most behavior in insects; neurons have receptor dendrites that are connected to the central nervous system, to which impulses travel—a standard locomotive reaction in insects that is known as orthokinesis. A response to air is anemotaxis. To light: phototaxis. (Following the trend of other-axis words, transferring food by mouth [or anus] is known as trophallaxis.) Insects are celestial creatures in that they also respond to Earth’s magnetic poles. Evidence of magnetic field sensitivity can be found in termites, flies, ants, and others, improving their foraging direction.

  What’s exciting is not why insects function the way they do, but how. “The extreme density of neurons packed into a small volume,” writes neuroscientist Nicholas Strausfeld in Encyclopedia of Insects, “suggests that the largest insect brains have impressive computational power.” But describing the parts that make those brains function is difficult. Those microscopic bits of neuroanatomy are hit with the same nomenclature challenges that William Kirby and the early entomologists dealt with.

  Within the insect neuroscience community—yes, there is one—brain regions are often described without clear definitions, like “mushroom bodies,” “antennal lobes,” “lateral triangle,” “bulb,” and so on.10 The problem lies in the difficulty of understanding the synaptic goings-on of the nervous system without a universal lexicon. To solve this, Tokyo students Kei Ito and Kazunori Shinomiya established the Insect Brain Name Working Group. Building a 3-D brain map of Drosophilia flies as a framework viewable on x-, y-, and z-axes, they tripled the number of identified neuropils (brain wiring) in bugs. Arthropod neuroscientists have held over 25 meetings to map out the neuron, connective fibers, and neuropil boundaries since 2008.11 They’ve laid out a framework, properly identifying 47 regions, which “comprise the entire brain.” Now we have websites like VirtualFlyBrain.org for those wanting to explore an anatomical 3-D reconstruction firsthand.

  But what contributes to insects’ learned behavior? We’ve found parasitoid wasps who memorize odors and colors; flies who boost their vision; butterflies who learn to recognize plant shapes. Given their circuit board of neurons, how smart is an insect?

  To help answer this, Swiss entomologist Tad Kawecki conditioned fruit flies in the early 2000s. He studied their short-term memory by “infusing” pineapple-like substances with quinine. He left out two petri dishes—one with the tainted pineapple and one with an untainted orange substrate. Following the fruity scents, the flies would land on the quinine-infused pineapple and reject its bitter taste. Later, when they were offered the plates with both fruits on it again, their fly brains were clever enough to associate pineapples with a bitter taste, and gravitated instead to the oranges. Next, Kawecki took eggs from those flies and reared up to 51 generations “favor[ing] associative learning.” By the twentieth generation, evolutionary change was obvious. “The experimental flies developed an association between the chemical cue and the medium faster than the control flies,” he writes in his paper. They had a “higher learning rate.” But with a lack of genetic variation, there was a “slowdown” in evolutionary change; so, regrettably, there will be no dystopian Fly Kingdom mutant overlords for us.

  Building on this research, a 2007 study pointed out that flies who “learned faster … forgot sooner.” Grasping more of that learned behavior could lend insight into how cognitive traits evolve in other species. For example, there’s the fruit fly “fight club” at Caltech, where males were bred specifically to become more aggressive. Scientists discovered a substance known as tachykinin in a certain neuron in male flies that is the source of their aggressive behavior. It turns out this chemical is similar to the ones that drive aggression in mammals, like us. Such defensive tendencies are visible across all insect species.

  From the Gospel of E. O.: “If ants had nuclear weapons, they would probably end the world in a week.”

  Fire ant workers will spread-eagle a rival queen’s legs while others sting her repeatedly. Captive wasps will gouge predators with their pointy genitalia to break free. Bombardier beetles shoot a jet of boiling chemicals at predators. Some assassin bugs wear the bodies of their kill to blend in among their next victims. Vinegaroon arachnids spray vinegar-scented acid from beneath their whiplike tails. And besides reaching speeds of 5.6 mph—fast enough to temporarily blur their vision—tiger beetles dismember prey with massive jaws and liquefy them into smoothies.

  My belief is that, though we cannot naturally turn any species into goop, we share many common traits with insects, or at least find many recurring, analogous ideas. In digging up their microcosm habitats and analyzing their behavior, we can appreciate not only their physiology but their inherent drive, and the engine behind their global contribution.

  As we’ll see, to know insects is to know a larger function of our life, social or solitary as they may be. But with their aggressive tendencies, hopping into bed with insects can prove to be viol
ent, torturous, and often fatal.

  Three

  “Even Educated Fleas Do It”

  Sexual suicide. Prostitution. Necrophilia. You’ll find that the makings of celebrity scandal can also be found in the details of insect reproduction. There’s nothing more compellingly absurd, alien, or violent than some bug-on-bug action. Those aggressive tendencies, to put it mildly, were devised as a means of allowing females to spawn safely and reproduce in volume because individually bugs can’t build buried cities. But being extraordinary baby-makers assures their critical input in our biosphere—even at the risk of dismemberment.

  Some male praying mantises, we’ve heard, famously risk decapitation after sex via their partner’s scythe-like forelegs, but at least their dignity is intact. Others, however, are at times split in half upon mounting female mantises. Brain removed, the nerve cells enable the male’s abdomen to continue impregnating her. Male honeybees aren’t as fortunate. Drones play a singular role: impregnate the queen. To ensure that, they ejaculate so hard their rocket-propelled gonads burst like a sexual time bomb. Dragonflies and their doppelgänger damselflies—as part of what entomologist J. E. Lloyd calls a “veritable Swiss Army Knife of gadgetry”—have a hook to yank out sperm deposited by other male rivals. Flea-sized Neotrogla aurora females common to Brazilian caves, meanwhile, are endowed with a spiky, inflatable “penis” that docks into males for up to 70 hours of sex. On the prettier side of things, there’s the majestic, synchronous, filigreed dance of Pteroptyx fireflies, who charm potential mates through photic signaling. Still, males need to possess a sizable nuptial gift—a protein-packed sperm sac—to court the ladies. Sometimes female insects simply can’t be wooed. Bedbugs get it the worst as evidenced by the number of scars on the female’s abdomen, signifying the number of times they’ve been (forcibly) mated with/gored by a male’s bullhorn-tipped penis; a horrifying “traumatic insemination” that makes prison shankings look like amateur hour.

  Amber Partridge skillfully prevents such gruesome behavior. She is an invertebrate biologist at the Butterfly Pavilion in Westminster—the nation’s first free-standing insectarium—a few miles north of my Denver apartment. As the zoo’s head entomologist, Amber performs a variety of buggy upkeep. Chief among them is her knack for refereeing tarantula intercourse. It’s important to state that she leads this breeding program not out of voyeurism but for growth study. As far as arachnology goes, these programs are few and far between. It’s one reason why Amber has dedicated the past five years to researching tarantulas’ life spans, molting, and survival rates. The more she breeds here (five pairs once produced 1,981 spiderlings), the less are removed from natural habitats. When I asked why she does it, I expected some hobbyist response. Instead, it was worrisome: within the next 10 years, she said, the majority of known tarantula species will be extinct.

  True or exaggerated, the threat of extinction raises an interesting idea: bugs—those creepy crawlies keeping the world’s ecology humming along—might be abundant. But despite their fecundity and ubiquity, or perhaps thanks to it, their extinctions surpass those of any vertebrate. In 2005, biologist Robert Dunn peered over what meager calculated extinction figures existed and inferred in his Conservation Biology paper that over the past 600 years there have been 44,000 species lost. Only 70 of them were actually recorded. “The biodiversity crisis,” he writes, “is undeniably an insect biodiversity crisis.” So, how will they fare in the future?

  If Dunn’s crystal ball is any indication, it’s not looking good. A conservative ballpark predicts that there will be “57,000 insect extinctions per million species on Earth” by 2050, of which less than 1,000 are currently listed as endangered worldwide. Other biologists claim a quarter of all insect species are threatened. Due to bottlenecking from population growth and chemical extermination, those bugs in decline will most likely slip away unnoticed—or, as in one case, while tucked away in a storage cabinet. Such was the discovery made by an entomologist in the 1960s who had neglected to describe a katydid specimen he collected from the Antioch Dunes in Northern California until years later. When he and others returned to the sand dunes looking for a living specimen, there were none. Hence its name Neduba extincta. Dunn asserts the causes for such documented extinctions are due mainly to the same ones kicking other animals off the planet—namely, “habitat loss and overharvest.” But in terms of ecological function, unlike vertebrates, the impact is dire.

  While an endangered mammal is a tearjerker, an endangered insect might be cataclysmic. In 2008, University of Montpellier’s Nicola Gallai took a bioeconomic look at 100 crops consumed by humans listed by the Food and Agriculture Organization of the UN and theorized that the worldwide economic pollination value of insects averages $216 billion a year.

  Rescue, though seldom, is under way. “Insect conservation,” Dunn notes, “remains the awkward ‘kid sister.’” Yet nonprofit organizations like the Xerces Society have succeeded in drawing public awareness and, my god, sympathy to endangered invertebrates for decades. Established in 1974, Xerces was named after a radiant blue butterfly last encountered in the 1940s; urban development in the Bay Area likely brought an invasive species that led to its presumed demise. Xerces has spearheaded conservation ever since the insect’s discovery, leading coordination efforts to save an array of “at-risk” and otherwise threatened bugs (placed on the Red List of Threatened Species), as well as partnering with various state and federal agencies to monitor and study vulnerable species and help create preserves. As mentioned in the book Nabokov’s Butterflies, the “first cause célèbre” of John Downey (the lepidopterist who discovered the Xerces blue extinction and later was a Society adviser) was that of the endangered Karner blue butterfly, which was actually first described by Vladimir Nabokov. But it wasn’t until 1992, after its habitat declined so much that only 1 percent of the population continued to exist, that the US Fish and Wildlife Service (FWS) listed it as endangered. Normally such a listing might simply impinge on the day-to-day activities of companies, farmers, developers, and landowners. However, the Wisconsin Department of Natural Resources took a different approach to habitat conservation by joining together 40 partners statewide. This, along with Xerces Society’s seed-distribution endeavors to create sources for beneficial plants like Project Milkweed—milkweed being the host plant to monarch butterflies—may hopefully pave the way for a 1,500-mile butterfly corridor along US Interstate 35.

  In 2015, the Obama administration worked with FWS to protect the iconic1 monarch by planting milkweed across the highway stretch. The route also outlines the black and orange butterfly’s migratory path from Texas to Minnesota. I should also mention that if bug extinction were the Titanic, butterflies and bees would be the lofty upper-class passengers claiming lifeboats. Thirty-five percent of the insect species listed on the FWS website are butterflies. Like bees, the reason for this is typically the butterfly’s utilitarian values such as pollination prowess and aesthetic pleasure during countryside frolics. But the monarch’s decline that began in the 1990s was unavoidable, as butterflies are generally good bioindicators of other problems. Twenty years ago it would’ve been possible to see 1 billion monarch butterflies migrate to Mexico and cluster, like gooseneck barnacles, on a forest of oyamel fir trees. Today’s latest count has them at 56.5 million. If the highway plan works, expect their numbers to quadruple by 2020.

  Many conservation efforts also find citizen science useful. To help take census of the decline of fireflies, the Vanishing Firefly Project launched a mobile app in 2013 to track firefly sightings in local habitats, getting an estimated count of fireflies. So far the project’s data—coming in from as far as Italy and Colombia—shows how low of a dispersion they have, and how imperative their environments are. But when the number of a surviving species seriously dwindles, and outdoor preservation alone won’t suffice, conservation efforts require a more stimulating hand.

  That’s where the insect Dr. Ruths come in.

  Ex-situ conservation is
a breed-and-release program. The New Zealand Department of Conservation’s success in saving Motuweta isolata (tusked wetas) from extinction is an excellent example of an ex-situ conservation effort. Wetas are a sluggish species—some, like the Deinacrida heteracantha, can reach about 2.5 ounces and can eat a whole carrot. Rescue efforts began in 19932 after invasive rats had largely destroyed the population. By 2001, scientists released ex-situ juveniles, as well as adults fitted with harmonic radar transponders for tracking, into the predator-free Double and Red Mercury Islands. The released adults led researchers to other adult wetas. Two years later, island-bred tusked wetas appeared. Now the conservation department is raising other weta species to establish on nearby islands. The Aukland Zoo also used this approach. Extra staff fed hundreds of newly hatched wetas that, if lined along Interstate 35 instead of migrating monarchs, would haunt vacationing families all the way to Corpus Christi. Still, looking like a ’roided-out, long-horned grasshopper bodes much better than being a tarantula.

  “We work with uncharismatic species,” says Amber Partridge, our matchmaker and biologist at Butterfly Pavilion. “People would rather donate to panda bears.” Simply put, we enjoy prettier things. Tarantula eradication proves it.

  As a spider, unless you’re gifted in calligraphy à la Charlotte’s Web, you’re likely to be greeted with animosity. Myths plague the Mexican redknee tarantula—it is thought to kill horses, cows, and children. And so villagers reportedly pour gasoline into redknees’ burrows or rev the accelerator if they spot redknees on the highway. And India’s peacock tarantula, a sapphire diamond with eight legs, rediscovered after 102 years, was listed as critically endangered due to the pet trade, negligent construction, and deforestation. These issues also caused the rapid decrease of nine similar species in India—a country where, as scientists unsurprisingly discovered in 1998, “there was not a single tarantula expert.”