Bugged Page 7
What sparked his initial interest was a firebug. He and long-time colleague Anders Møller were attending a conference in the Ukraine during the twenty-fifth anniversary of Chernobyl and exploring the nearby city of Pripyat. Crawling among the abandoned buildings, the rust-coated Ferris wheel, and the other eerie elements of the city evacuated by 50,000 people were mutated firebugs. “They’re cryptically colored in this red motif on their backs, sort of resembling an African face mask.” Møller grabbed one and said, “Look, Tim! This one’s missing an eyespot!” Some dots looked fused together. As the researchers expected, their abnormalities were related to the background radiation. Møller and Mousseau have been taking samples of fauna ever since. Together, they trudged these zones led by the static ticks of Inspector Alert Geiger counters. A couple of sprays of a water mister revealed odd spider webs as imperceptible as the radionuclides surrounding them.
“We noticed many of the webs were peculiar looking,” Mousseau says. In the photos he’s sent me from Fukushima, the cobwebs wilt asymmetrically, some with a gapping pupil like a lazy eye. “We were new to Japan, and you know, maybe Japanese spiders aren’t as good as making symmetrical webs as spiders elsewhere,” he laughs. “The bottom line was there are a higher frequency of abnormally structured web architecture—less uniform—in the radioactive areas. And this is true in both Chernobyl and Fukushima.” They hypothesize the oxidative stress associated with radiation affects the neurological development in spiders, causing the misshapen webs. That aside, spider populations seem to increase with radiation—possibly a result of weakened, irradiated prey. Meanwhile, other insects decrease. On one particular trip, he hefted four UV-light-emitting moth traps powered by car batteries to collect kilos of moths at night. He found an abundant difference in bounty between clean areas and places shrouded by radioactive fallout.
Like the firebugs that first entranced the two men, the mutations9 are not only obvious but also reproducible in laboratory settings. This is crucial when trying to study the heredity of abnormal traits. Malformations from radiation experiments date back to the early 1900s. Claude Villee used X-rays on flies, producing leg-like antennae or an extra palp growing from an eye. After the Fukushima meltdown, researchers in Okinawa re-created the same effects in Japan’s most common butterfly, the pale grass blue, by feeding them irradiated leaves. The results were menacing. Rates of “forewing size reduction, growth retardation, high mortality rates … color pattern changes” grew over generations, which implied an “accumulation of genetic damage.”
At the opposite end of that gene-churning spectrum, the Antarctic’s chironomid midge (or sandfly for you Midwesterners) can dehydrate itself to survive at 5 degrees Fahrenheit without ice crystals destroying its cell membranes. Its relatives in the Nepal Himalayas can bear going down to 3 degrees and still happily graze off blue-green algae growing on glacial ice. Ice worms—inch-long, black annelids—burrow into solid ice like earthworms do into soil. Finding them is difficult. Especially as melting ice pushes them further into Alaska snowfields. “We’re interested in how they’ve adapted to ice,” says Dan Shain, who’s spent 15 years tracking these worms that NASA loves so much. The space agency funded $214,000 for research to look into how life might be sustained in icy habitats across the galaxy. The mystery, he told one reporter, is figuring out why the worms have an enzyme that “skyrocket[s]” their metabolism—specifically adenosine triphosphate (ATP), which transfers intracellular energy. Due to such intense energy, ice worms “thrive” in below-zero climates and disintegrate at temperatures over 40 degrees. Shain and his colleagues believe ice worms’ tolerance to cold is related to a subunit of the ATP synthase complex. This “throttle” protein has been modified by ice worms “in an unusual way,” Shain said in an e-mail, since the protein adds an 18-amino-acid extension that increases the worm’s energy levels.
Finding such adaptive abilities puzzles and amazes nearly every biologist. I’d be interested to see how hardy ice worms would be in a lab setting. How many generations it would take to adapt to 40-plus-degree habitats. I know after talking to Marlene Zuk that witnessing those changes in person can be unnerving. That’s what happened in 1991 when Zuk crawled over a Hawaiian grass field at night, looking for crickets that might contain parasites, headlamp illuminating an abundant amount of Teleogryllus oceanicus crickets expressionlessly staring back at her. Only a few of them were singing. By 2003, they were chirpless and bountiful.
“If you know anything about crickets,” says Zuk, “then calling is the sort of thing they do.” Male crickets have a stridulatory apparatus on their wings with teeth and a scraper, known as flatwings, that produces sound when rubbed like a bow to a fiddle. The emitted chirps10 act as a beacon for potential mates in the area. As she explains in a paper entitled “Silent Night,” a scanning electron microscope’s micrograph of the flatwings in T. oceanicus showed the same apparatus as other crickets, but at a much reduced size. Nature pressed the mute button. These chirpless crickets, she says, are an example of rapid evolution.
Those crickets that Zuk discovered in the field at the conference, T. oceanicus, were originally from Fiji, Tahiti, and Samoa but had been on Hawaii since 1877. Some speculate the crickets were introduced by Polynesian colonizers 1,500 years ago who, folklore has it, believed crickets were their deceased relatives. But their move to Hawaii brought them a new experience that has affected their evolution: a parasitic fly hones in on the crickets’ broadcasted mating call and deposits mobile larvae on it. Larvae then develop inside and, as Zuk’s students say, “eat all the gooey bits.” After only 20 generations, the crickets changed their gene frequency to radio silence. It wasn’t just behavioral—they were “physically incapable of producing sound.” Visit Kauai today, and you’ll find about 90 percent of T. oceanicus males are hush-hush. On Oahu? Half won’t make a peep. What’s really perplexing is that while T. oceanicus is the same on both Kauai and Oahu, an analysis shows the single gene enacting the chirpless wing morphology mutation is different. So in order to continue reproducing, the crickets utilize a “bait-and-switch strategy” by lingering near males of the same species that can still call, and, in a cold-hearted, frat-boy gesture, swooping in once a female appears.
Occasionally a species that’s gone extinct will turn up resurrected decades later. This phenomenon is aptly called the Lazarus effect—an act of perseverance exhibited by the tree lobster last seen off the coast of Australia in the 1920s but that is alive and well today.
Ball’s Pyramid, near Lord Howe Island in the South Pacific Ocean, doesn’t feature rounded contours but rather is a pointy remnant shield volcano. In 2001, a team of surveying researchers found moist, green frass (i.e., insect excrement) in a shrubby patch on Ball’s. The frass belonged to the Dryococelus australis tree lobster of yore. Sure enough, later that same night, team members found live tree lobsters after an 80-year absence. After being nursed with a concoction of calcium and nectar by conservationists at the Melbourne Zoo, a female D. australis produced enough eggs for the species’ ultimate recovery.
But if the question is whether all insects will survive the twenty-first century, the answer undoubtedly is no. And the ecological consequences are hard to predict. In his book Insect Diversity Conservation, Michael Samways highlights the fact that global climate change—the grandest of humanity’s impact—“involves multiple stressors and synergisms.” Forecasting future outcomes is difficult, he concludes, but one thing is certain: “The insect diversity that we are encountering today at any one site will not be the same for our grandchildren.”
* * *
Some insects disappear with little trace evidence as to why. And all that’s left of them? Their stories.
In 1875, a Plattsmouth, Nebraska, telegrapher messaged nearby towns to verify and gauge a dark cloud 1,800 miles long and 110 miles wide composed of 10 billion locusts. To this day, it remains the largest locust swarm on record. This pest known as the Rocky Mountain locust was widespread in the Midwest. It caused
$200 million in crop damage and was rumored to derail locomotive wheels as well as western expansion plans. Yet less than 30 years later, the abundant Rocky Mountain locust went extinct; the last individual locust collected was in 1902.
Mysterious as their vanishing act may be, the root obviously lies with humans. Abundance of this kind of locust could not combat the national programs for their extermination.11 Bounties were put on their heads. A bushel of dead locusts got you a dollar. A bushel full of egg pods got you five. But as Jeffrey Lockwood said in a 2001 American Entomologist paper, “The conservationist’s argument that we must save a species because we need their ecosystem services is feeble.” My understanding is that he wants to use the locust’s story to illustrate a larger point. Dominant as insects may be, they are not a guaranteed place-holder in a world Homo sapiens occupy. After all, it only took some cattle and plows to eradicate the Rocky Mountain locust. Until 1990.
Granted, the locusts were 400 years old. Using geological analyses to plot an ancient locust swarm, Lockwood found rotted specimens in a northwestern Wyoming melting glacier. They were the first collected since 1902. Were it not for global warming, writes Lockwood, the locusts may have not risen to the surface—albeit this time dead. “A century ago, human alterations of the environment caused the demise of the Rocky Mountain locust; and today, the ghosts of these insects warn us of an even more serious threat to the natural world,” Lockwood said. The adaptive insect design that has survived for millions of years is being put to the test on an unprecedented level.
It’s a global threat entomologists like Amber Partridge strive to prevent.
In the Butterfly Pavilion’s humidity-controlled Rearing Room are various caged species getting lucky: green leaf beetles, man-faced bugs, Macleay’s Spectre stick insects wobbling in a rocky sway, Red List-ed tarantulas, Simandoa cave roaches now extinct in the wild. The fecundity produces a damp, sodden atmosphere.
This go-around, Amber starts off with female Rosie no. 119 joined by male GRG2, short for Grammostola rosea and the alphanumeric name G2. Also, I’m holding the conductor’s baton—a size 12 paintbrush I’ll use to tempt the pair. “What you’re going to do,” says our matchmaker standing beside me, “is take the brush and rub the palps like this.” My hand quivers as the bristles approach G2’s outstretched pedipalps. As you’ll recall, these hairy straws store their semen, sucked up by the tip of their thorny embolus. My brush, frayed from years of coaxing, feels light against his pedipalp, which falls limp after each stroke. It feels like petting a very indifferent cat. I warily repeat the gestures back and forth, tickling the male and female with pheromones.
“Now you can start moving him toward her a little bit before she tries to climb out of the cage,” says Amber, tone as calm and cautious as a DMV instructor. This is difficult. They barely budge. Prod one way, they go the other. “So,” she says slowly, “guide him back towards her.” I manage to steer them to opposing sides of the cage. As Amber retrieves another male, I continue. The spiders flinch with each rub. I try to imagine if I’d appreciate being touched like this. How consensual is this? Meanwhile, jeers come from a box of hissing cockroaches on the Rearing Room table.
There is a danger component, so I must be vigilant. “I’ve had some pretty bad injuries where she’s gotten her fangs into him,” Amber tells me. “She’ll inject venom if she hasn’t eaten in a while.” She notices they’re in the same position. “Ugh, they’re so teenager-ish … Dude, you know what you have to do,” she berates G2.
I relinquish the conductor’s baton to the matchmaker. Eventually, we call quits on the Rosies and grab a pair of curly-haired tarantulas. Almost immediately the male jumps her from behind—“Sneak attack!”—and then proceeds to clumsily tap dance on her head. Believe it or not, this is a good thing. “Oh my god, this is amazing!” says Amber. “We’ve all seen these guys at the club. Just sayin’.”
The moment passes. “She wasn’t rejecting you, she didn’t understand.” But the damage is seemingly done. Amber returns him to face forward, stickhandling them like stubborn hockey pucks. And then—a grand slam! Or rather intense flailing as the male makes a wrong move while crawling beneath the female. There’s a quick struggle with the female wrestling the male and I jump back and scream, “Oh, shit!” My presence killed him, I think. But the alarm dies down as they face and seek out each other with intertwining legs in a Greco-Roman grapple. He drums his pedipalps on her underside, and sticks his embolus into her epigynum, filling it like a gas nozzle fills a tank.
She gets backed into the cage’s corner and bares her two very ominous fangs. “She’s getting mad.” And possibly a little hungry. Amber breaks up the quarrel using the paintbrush. The mating was a success.
Next, data collection. Date, humidity, start/end time, and attempts get logged as well as comments. “New sperm web + short copulation” or an “A+” if sex goes smoothly. Occasionally a male will break off his embolus within a female’s copulatory cavity to prevent other males from reproducing. I’m a little surprised how rapidly it all happens after the hours put in. “That’s it?”
“That’s it,” she tells me. Except now the potentially gravid female gets a name. The matchmaker bestows the honor on me. Thinking about the surprising celebrity spider fanatic/international model I learned about in chapter 1, I name her “Claudia.”
If Claudia ends up being gravid, she’ll produce an egg sac that Amber will delicately confiscate and incubate herself. Egg sacs can contain 1,000 spiderlings, four of which can fit on a thumbtack. Bug reproduction is bountiful and strange, and the variety makes the process truly impressive, especially given bugs’ proclivity for adaptation. How warm those breeding environments are can either damage the insects or generate swaths of breeding grounds. Mix in human travel, and we get our contentious relationship with pests and changes that have reshaped history. And it’s something we’ll have to face up to if we plan to live in their world.
Four
The On-Flying Things
By August 29, 1793, a month had gone by since yellow fever broke out in Philadelphia. Sparse gunfire echoed through forlorn streets as carts full of bodies were wheeled about. That’s when the lively liquid contents of the public water barrels caught the eye of a person known to history only as A.B. “Whoever will take the trouble to examine their rainwater tubs,” A.B. wrote in Dunlap’s American Daily Advertiser, “will find millions of the mosquitoes fishing about the water with great agility.”
Breeding conditions favored Aedes aegypti, and yellow fever crushed the former US capital. Over a four-day period in October 1793 alone, 386 people died, the toll reaching 5,000 by year’s end. Ultimately, nearly half of the city’s 50,000 inhabitants left, but the significance of A.B.’s offhand observation of mosquito larvae would not be understood for another century. The war being waged—though the concept might imply a fair fight—would make General Sun Tzu proud. “Be extremely subtle, even to the point of formlessness,” he writes in The Art of War. “Be extremely mysterious, even to the point of soundlessness. Thereby you can be the director of the opponent’s fate.”
Epidemics have influenced wars, politics, and economies for millennia, as tiny insects known as vectors carry viral infections that bring devastation. The deftness of mosquitoes, fleas, and lice has stopped armies, delayed construction of grand projects, and changed the face of human civilization. During the yellow fever epidemic of 1793, George Washington’s administration was temporarily dispersed. Patients filled hospitals, and the mansions that were used to house the infected were described in Jim Murphy’s An American Plague as “great human slaughterhouse[s].” Bloodletting sometimes occurred up to 150 or so times a day. Containers filled so rapidly the phlebotomies moved outside to the cobblestone roads. The uninfected had little else to resort to but folk medicine, huffing vinegar-soaked hankies and burning gunpowder to “purify the air.” This was only the first outbreak in the United States. There would be many more.
Countries that took part i
n the slave trade, and thus transported mosquito vectors, were the ones most likely to experience yellow fever. The West Indies were hit in 1648. As slavery in the United States increased twofold in the eighteenth century, foreign mosquitoes and an expanding population primed the country for the viral storm. Jim Murphy helps put the casualties that stretched from Boston to Savannah in perspective. Over the course of three outbreaks starting in 1853, New Orleans and Memphis reached a total of 16,000 dead. Rioters on Staten Island burned a quarantine hospital that had treated infected patients to the ground in 1858. By 1905, the outbreaks were over, shortly after their cause was discovered.
Following the Philadelphia epidemic, construction on the new US capital began on cheap, undesirable swampland between Virginia and Maryland. A breeding ground for mosquitoes, the gaseous land was associated with disease. Malaria actually means “bad air” in Italian. “Washington, DC exists in part today because of malaria,” says US Army research entomologist Mike Turell on a phone call from Fort Detrick. “If you lived around a swamp, you got malaria. It did not take a rocket scientist to figure that out back in the 1500s.” Turell, now retired, has studied arthropod-borne viruses, aka arboviruses, for nearly 40 years. When newspapers need a scoop for the next headline-fetching epidemic, Turell is the man they call.