Wicked Bugs

by Amy Stewart

  In 2009, an archeologist exhuming the bodies of Rwandan gorillas to do research on evolution woke up one morning to find a river of driver ants streaming through the excavation site. “Just so you know,” said one of her colleagues, “this day is going to suck.” The scientists donned protective gear and tried to stay as far away from the swarm as possible. By the end of the day, the ants had eaten their fill and moved on. When the team returned to the dig, they realized that the driver ants had done them a favor by removing every other bug from the soil, allowing them to retrieve clean, intact skeletons.

  BULLET ANT

  Paraponera clavata

  The bullet ants gets its name from the fact that its bite feels like a gunshot. Those who have had the misfortune of getting bitten by this inch-long South American ant say that the pain is overpowering for several hours, then subsides over the next few days. Some people are temporarily unable to use the limb that’s been stung, and some report nausea, sweating, and shaking after the attack.

  British naturalist and television star Steve Backshall deliberately braved the sting of the bullet ant when he was filming a documentary in Brazil. He joined members of the Satere-Mawe tribe in a male initiation ritual that involved being stung continuously by a swarm of ants for ten minutes. The pain left him screaming, crying, and writhing on the ground. Soon he was drooling and nearly unresponsive, thanks to the powerful neurotoxins in the venom. “If there’d been a machete to hand,” he told reporters, “I’d have chopped off my arms to escape the pain.”

  ARGENTINE ANT

  Linepithema humile

  This tiny, dark brown ant species probably slipped into New Orleans in the 1890s onboard a coffee ship coming from Latin America. The mild and damp coastal climate proved so favorable that the ants spread across the Southeast and west to California. Citrus farmers sounded the alarm as early as 1908, but their attempts at controlling this invasive ant proved ineffective. The latest news about the Argentine ant’s ability to form supercolonies that span hundreds of miles sounds like something right out of a horror movie.

  These three-millimeter long ants are surprisingly aggressive considering their size. They don’t sting or bite people, but they have wiped out colonies of native ants that are ten times their size. The loss of those native ants means the disappearance of a food source for creatures higher up the food chain, including California’s coastal horned lizard, which has not only lost its favorite food source, but also must face attacks from swarms of Argentine ants.

  The attempts to control fire ants has been so expensive, time-consuming, and ineffective that biologist E. O. Wilson has called it the “Vietnam of entomology.”

  But the Argentine ant’s favorite food source is not other ants; it is actually honeydew, the sweet secretions of aphids and scale. To make sure that these pests produce enough honeydew, the ants actually “farm” the aphids and scale, protecting them while they do their damage to rosebushes, citrus trees, and other plants, and even carrying the pests around to make sure they find enough to eat.

  The disruption caused by these ants, which can exist by the millions under just one single-family home, is almost impossible to fathom. They have driven other ants, termites, wasps, bees, and even birds from their nests, and caused damage to agricultural crops. They act in an incredibly organized, militaristic fashion, never going to war with one another, always working together to accomplish their mission.

  In fact, entomologists now realize that the population of Argentine ants that extends from San Diego into northern California is one giant supercolony of genetically similar ants. A European colony extends all along the Mediterranean coast, and supercolonies in Australia and Japan are also well established. The members of all of these colonies are so closely related, and so unwilling to fight one another, that they can almost be thought of as one global megacolony that acts as a single entity in carrying out its mission.

  PAINFUL

  Giant Centipede

  SCOLOPENDRA GIGANTEA

  In 2005, a thirty-two-year-old psychologist was watching television in his north London home when he heard a strange rustling sound under a stack of papers. He got up, expecting to find a mouse, but instead a nine-inch-long, prehistoric-looking creature with more legs than he could count scuttled away. Fortunately, he had the presence of mind to grab a plastic container and scoop it inside without touching it.

  SIZE:

  Up to 30 cm

  FAMILY:

  Scolopendridae

  HABITAT:

  Moist environments such as the undersides of rocks, leaf litter, and the forest floor

  DISTRIBUTION:

  South American forests

  The next morning, he took it to London’s Natural History Museum, where an entomologist peered into the bag, expecting to find the sort of run-of-the-mill insect that visitors bring to the museum every day. But when he “produced this beast from his bag I was staggered,” the entomologist told reporters. “Not even I expected to be presented with this.”

  The beast in question was the world’s largest centipede, Scolopendra gigantea. This enormous South American creature can reach a foot long, and its bite delivers a powerful dose of venom. It may have twenty-one or twenty-three segments; from each segment protrudes one pair of legs, with the legs on the first segment being a pair of venom-bearing claws called forcipules. The bite of the giant centipede is powerful enough to cause swelling, pain that radiates up and down the limb where the bite occurred, and even a small amount of necrosis, or dead flesh. Nausea, dizziness, and other such symptoms are not uncommon with a bite as severe as this, but the wounds usually require only simple medical care to treat the symptoms.

  The centipedes were hanging from the cave by their last few legs and catching bats in midair, demonstrating a rather frightening level of forethought and ingenuity.

  Although people will most likely survive the bite of a giant centipede, small creatures like lizards, frogs, birds, and rats are not so lucky. A team of researchers in Venezuela found one of these giant centipedes hanging upside down from a cave wall, happily munching away on a small bat. After observing the same behavior several times, they realized that the centipedes were hanging from the cave by their last few legs and catching bats in midair as they flew by, demonstrating a rather frightening level of fore-thought and ingenuity.

  In spite of their name, centipedes don’t all have a hundred legs. They are distinguished from millipedes in that they have one, not two, pair of legs attached to each segment. The precise number of legs varies by species. And although all centipedes do bite, many are too diminutive to inflict much pain, and some have such small, soft mouthparts that they can’t even pierce human skin. (Regardless, centipedes should never be handled with bare hands.) The house centipede Scutigera coleoptrata, found throughout North America, might look intimidating, with its fifteen pairs of strangely long legs, but its bite delivers little or no pain. It does eat bed bugs, silverfish, carpet beetles, and cockroaches, so its presence might indicate a more alarming sort of infestation.

  Centipedes lack the kind of waxy covering that keep some insects from drying out, so they must stay in moist areas to survive. They breathe through tiny openings behind their legs, and the amount of water they exhale through these openings puts them at even greater risk of dehydration. Their mating practices are surprisingly dispassionate: the males deposit their sperm on the ground where the females can find them. While some males will nudge a female in the direction of the sperm, they otherwise have little romantic contact. The female giant centipede, however, will brood over her eggs until they hatch, even protecting them from predators the way a bird in a nest guards her young.

  The pain inflicted by a centipede is mostly related to its size and, as a consequence, the amount of venom it injects. People living in the southwestern United States may rightfully fear the giant redheaded centipede, Scolopendra heros, which, at about eight inches long, can deliver a whopping bite. A military physician who has been bitten re
peatedly by this species described the pain as a ten, on a scale of one to ten, and reported that over-the-counter medication offered no relief, but that the discomfort and swelling receded completely after a day or two.

  And as for the British man who found the giant centipede in his living room? Museum officials originally speculated that it could have hitched a ride from South America to England in a box of imported fruit. Eventually, however, the man’s neighbor came forward and confessed that he had purchased the centipede at a local pet store and intended to keep it as a pet. (They can live for up to ten years, making this a long-term commitment.) The creature was returned to its owner where, it is hoped, it won’t be allowed to pay any more visits to the neighbors.

  Meet the Relatives There are about twenty-five hundred species of centipedes around the world; the other members of the giant centipede’s family are found mostly in the tropics.

  DESTRUCTIVE

  Mediterranean Fruit Fly

  CERATITIS CAPITATA

  In 1929, a Florida entomologist declared: “The presence of the Mediterranean fly in Florida necessitates a warfare of continental dimensions . . . It is an enemy the United States has never before been compelled to fight. Nothing will be gained by underestimating the seriousness of its ravages, for it works rapidly, silently and persistently, and so far has known no parasitical foe.”

  SIZE:

  6.3 mm

  FAMILY:

  Tephritidae

  HABITAT:

  Tropical areas and orchards where fruit is plentiful

  DISTRIBUTION:

  Africa, North and South America, Australia

  And what a war it has been. The Mediterranean fruit fly is so widely feared that when a single fly was found at the Miami International Airport in 1983, it made headlines in the New York Times. The fly was even flown to Washington, DC, for a pregnancy test, where, to everyone’s relief, it was proven infertile.

  The fly had already been in the news a great deal. In 1981, California’s governor, Jerry Brown, faced a terrible political quandary: allow aerial spraying of malathion to kill the bug, which would alienate his environmentalist supporters, or refuse to allow it, which could destroy California’s multibillion dollar agricultural industry. He held off spraying as long as he felt he could, but ultimately families in Los Angeles, San Jose, and other areas awoke to the sound of helicopters spraying pesticide over their neighborhoods at night. Those who objected to the spraying were treated to the sight of Brown’s director of the California Conservation Corps drinking a glass of diluted malathion at a press conference to prove its safety.

  Rumrunners smuggling in bootleg liquor from Bermuda packed their bottles in straw that harbored the flies.

  The Mediterranean fruit fly is native to sub-Saharan Africa and probably hitched a ride to the United States on imported produce. (Prohibition may have had something to do with it as well: rumrunners smuggling in bootleg liquor from Bermuda packed their bottles in straw that harbored the flies.) Because every new appearance of the fly in America has been met with strong eradication efforts, it has not yet permanently established itself here.

  The fly completes its entire life cycle in just twenty to thirty days. The females deposit their eggs just under the skin of a fruit — often citrus, apples, peaches, or pears — and might fill that hole with several dozen eggs at a time. The eggs hatch and the larvae immediately begin eating the fruit, rendering it useless as a crop. They leave after a week or two — the exact time frame depends upon the fruit’s ripeness and the weather — and drop to the ground for a pupal stage that lasts a couple weeks more. The adults emerge, mate, and the females quickly lay a batch of eggs. In good weather, adult fruit flies might live for six more months, nibbling on the crop and laying eggs the whole time. As many as 250 varieties of fruits and vegetables can play host to the flies.

  The 1981 spraying campaign kept the fly at bay — for a while. The state spent $100 million to control the pest, only to see it reoccur eight years later. Another round of aerial spraying, coupled with the release of sterile male flies, the installation of traps, and a strict quarantine, averted another disaster. The fly reappeared in 2009, bringing on another round of quarantines and other control measures. Similar efforts have been tried elsewhere in North America, and in South America and Australia, where the pest has threatened crops.

  One of the strangest moments in the so-called medfly’s history occurred in December 1989, when a group of ecoterrorists who called themselves “the Breeders” sent a letter to the mayor of Los Angeles threatening to release swarms of medflies if they didn’t agree to halt aerial spraying of pesticides. In fact, officials did notice unusual patterns of medfly infestation that might have resulted from sabotage. No one was ever caught, and many officials suspected that the threat was merely a hoax.

  Meet the Relatives There are about five thousand species of fruit flies in this family, including Bactrocera oleae, the olive fruit fly; Anastrepha striata, the guava fruit fly; and Dacus ciliatus, the lesser pumpkin fly.

  HORRIBLE

  Millipede

  TACHYPODOIULUS NIGER, OTHERS

  In general, a millipede is not a particularly threatening creature. Unlike centipedes, which actively hunt for prey and inject their victims with venom to subdue them, millipedes creep slowly along the ground, scavenging for dead leaves. They are called “detritivores” for their habit of sifting through the detritus left at the base of plants and breaking it down further to help the cycle of natural composting continue. When attacked, most millipedes do little more than curl into a ball and hope their tough body armor protects them. So what’s not to like about these peace-loving vegetarian recyclers?

  SIZE:

  60 mm

  FAMILY:

  Julidae

  HABITAT:

  Leaf litter and forest floor where decaying vegetation is abundant

  DISTRIBUTION:

  Found throughout Europe, particularly in the United Kingdom, Ireland, and Germany

  Their sheer numbers, for one thing. Millipede invasions are not only creepy, they’re destructive. Stories of millipedes swarming over railroad tracks have been in the news since the advent of the railroad, but some of the more recent accounts are truly astonishing. Express trains outside Tokyo were brought to a halt in 2000 when the creatures swarmed over the tracks. Their crushed bodies created a wet, squishy mess that made the wheels slip. In Australia the same thing has happened: a nonnative Portuguese millipede, Ommatoiulus moreletii, infested rail lines, forcing the delay or cancellations of trains that simply couldn’t gain traction on the slippery tracks.

  The situation is even worse in parts of Scotland, where the European black millipede, Tachypodoiulus niger, is such a nuisance that residents of three remote villages in the Highlands have been forced to resort to nighttime blackouts to keep the millipedes, which are attracted to light, from creeping into their homes at night and massing around bathrooms and kitchens. A local postmistress told reporters: “They are horrible. They start in April and last year they were still coming in October. It’s hard to believe how bad it gets unless you are here and see them.”

  Monkeys in Venezuela rub the millipedes into their fur and use their secretions to keep mosquitoes away.

  A town in Bavaria tried the blackout strategy, but gave up and eventually built a wall around the town to keep millipedes out. The wall, which surrounds the town of Obereichstaett, is made of slick metal with a lip that the creatures can’t cross. (Homeowners in Australia have used something similar for years to keep millipedes out of their houses.) One resident of the town said that before the wall went up, he couldn’t walk down the street without crushing dozens of them. The smell alone was unbearable.

  Millipedes, which can be identified by the fact that they have two pair of legs per segment, do produce a number of unpleasant compounds as a defense mechanism. Some species release hydrogen cyanide, a toxic gas that they formulate in a specialized reaction chamber if attacked. This gas i
s so strong that other creatures placed in a glass jar with these millipedes will be killed by it. The species Glomeris marginata produces a chemical compound similar to Quaaludes, which it uses to sedate the wolf spiders that attack them.

  These defensive chemicals are rarely harmful to humans; a person would have to deliberately cover themselves with the secretions of a millipede to experience a rash or burn from them. And, in fact, monkeys in Venezuela search for a four-inch-long millipede called Orthoporus dorsovittatus so that they can rub the millipedes into their fur and use their secretions to keep mosquitoes away.

  Meet the Relatives There are about ten thousand known species of millipedes, including the giant African millipede, Archispirostreptus gigas, which reaches twenty-eight centimeters in length and lives up to ten years in captivity, and the tiny pill millipede, which closely resembles the familiar, but unrelated, crustaceans in the Armadillidiidae family that we call sow bugs or roly-poly bugs.

  DANGEROUS

  ARROW POISONS

  Traditional methods of hunting and warfare sometimes involved extracting insect and spider venoms and applying them to the tips of arrows to make them more deadly. The particular species of insect or spider used has not always been described by observers or revealed by the poisoners themselves, but here, by tribe, are some of their recipes: