by Amy Stewart
This large, grayish brown spider is unusual in that it doesn’t spin a web and wait for prey to blunder into it. Instead, it prowls the floor of the jungle and even walks through the city, hunting for dinner late into the night. And while most spiders will scurry away at the sight of an aggressor, the Brazilian wandering spider stands its ground, rising up on its hind legs, ready for a fight. Anyone who swats at one of these spiders had better aim to kill, because if it survives a swat with a broom it might try to climb straight up the handle and bite.
Had the spiders escaped and starting dropping down from the overhead bins during the flight, the chaos would have been unimaginable.
The bite causes a flood of immediate and severe pain, which can be followed by difficulty breathing, paralysis, and even asphyxiation. One of the stranger symptoms of this spider’s bite is priapism, a persistent erection. Unfortunately, it’s not a sign of arousal but of severe envenomation. People who suspect that they’ve been bitten by a Brazilian wandering spider must seek immediate medical attention, but with proper care and a little luck they will survive.
There are eight species of wandering spiders in the Phoneutria genus, all found throughout parts of Central and South America and recognizable for their eight eyes, four of which form a box shape directly in the front of their face. The eight species are not all equally venomous, and most people who are bitten suffer only mild pain and recover fully. However, the most venomous species are capable of killing, with young children and the elderly at the greatest risk.
Because it sometimes climbs around in banana trees hunting for prey, the spider can end up as a stowaway in shipments of bananas, earning it the nickname “banana spider.” There are many harmless look-alike species that turn up in bananas and other cargo as well, and only a few scientists around the world are capable of making an accurate identification. It is difficult, therefore, to rely on media accounts of Phoneutria bites inflicted by spiders in imported produce. Nonetheless, a British chef unpacking a box of bananas in the kitchen was reportedly bitten by one in 2005; in spite of the pain and shock, he managed to grab his cell phone and snap a picture of the spider. The spider itself was later found in the kitchen, allowing experts to identify it and give the man the right course of treatment. He survived, but only after spending a week in the hospital.
Meet the Relatives Other members of the Ctenidae family are generally ground-dwelling spiders that hunt rather than spin webs, but less is known about the potency of their venom.
PAINFUL
CURSE OF THE SCORPION
Ascorpion bite may be painful, but it’s almost never fatal — for adults. Children are another matter. A California family vacationing in Puerto Vallarta in 1994 learned this the hard way, when their thirteen-month-old child stepped on a scorpion that had been hiding in his shoe. The boy started crying and frothing at the mouth and soon developed a high fever. At a local emergency room he stopped breathing a few times. Finally his parents called a San Diego hospital and had him flown there, where he was placed on life support. He did survive, but even hospital staff weren’t sure he would make it.
In a small child, the neurotoxic venom of a scorpion can cause seizures, loss of muscle control, and unbearable pain all over the body as it goes to work on the nerves. Until recently, parents had to watch helplessly as doctors did what little they could to manage the symptoms and sedate the child as the venom spread through the body.
Fortunately, a new treatment is in clinical trials now. At the Phoenix Children’s Hospital, parents are offered the choice of sedation for their child, or a new antivenin called Anascorp. The drug is administered intravenously and starts working within a couple of hours, usually allowing the victim to go home with pain medications that day. This breakthrough is being cheered in Arizona, where eight thousand people are stung every year, two hundred of them small children who suffer serious side effects.
Scorpions are found in desert, tropical, and subtropical areas throughout the world, and over twelve hundred species of these arachnids have been identified. As with spider bites, it is often difficult to prove that a particular species is responsible for a sting, unless the scorpion is captured and identified. But here are just a few to avoid:
ARIZONA BARK SCORPION
Centruroides sculpturatus
This is the scorpion most feared by Arizonans. It lives in the southwestern United States and in Mexico, nestling under rocks and piles of wood, but also making its way into homes. At only seven to eight centimeters in length, it is easy to miss, especially as it is active at night. Fortunately, scorpions glow under ultraviolet light, so Arizonans who wish to check for scorpions before they go to bed can use a blacklight flashlight, which is often marketed as a scorpion-hunting tool. The sting is considered to be the most painful of any scorpion in the United States, lasting for up to seventy-two hours and potentially dangerous to pets and small children. A related species, the Durango scorpion Centruroides suffusus, is found in the Chihuahuan desert and is one of the deadliest scorpions in Mexico.
FATTAIL SCORPION
Androctonus crassicauda
Soldiers in Iraq are warned to watch out for this highly dangerous dark brown scorpion, which gets its name from its menacing, oversized tail. The military classifies it as one of the deadliest scorpions in the world and warns that it can cause death by heart or respiratory failure.
DEATHSTALKER
Leiurus quinquestriatus
Another Middle Eastern scorpion that soldiers are warned to avoid, this light yellow and beige scorpion is easy to overlook in sandy soil, but its venom is highly toxic. An Air Force medic who was stung twice had to be flown to a hospital, where she was put on life support and given an experimental antivenin to save her life.
Scorpions glow under ultraviolet light, so Arizonans who wish to check under their beds for scorpions can use a blacklight flashlight.
TRINIDAD SCORPION
Tityus trinitatis
Found around Trinidad and in Venezuela, these diminutive creatures reach only five to six centimeters in length but deliver a painful sting that can cause pancreatitis. The deaths of a few children have been attributed to the venom of this scorpion, usually due to damage to the myocardium, or heart muscle.
WHIP SCORPION
Mastigoproctus giganteus
While not a true scorpion, this arachnid, also called a vinegarroon, uses an extraordinary piece of natural artillery to defend itself: rather than sting its enemy, it sprays a liquid made of 84 percent acetic acid. Household vinegar is only 5 percent acetic acid, making this something like the strongest vinegar imaginable. What is most extraordinary about this defense is the fact that it can whip its tail around and spray in any direction, sending predators running for cover.
DESTRUCTIVE
Brown Marmorated Stink Bug
HALYOMORPHA HALYS
Some residents of Pennsylvania and New Jersey dread the arrival of autumn, because it means the beginning of the annual invasion of flattened, grayish-brown insects from China. They crawl in the tiniest hole, able to gain entry through cracks around doors and windows, crevices in the attic, and ductwork. They make themselves at home, glad to be away from the winter’s chill and ready to spend the next several months enjoying indoor life.
SIZE:
17 mm
FAMILY:
Pentatomidae
HABITAT:
Orchards, agricultural fields, meadows
DISTRIBUTION:
China, Japan, Taiwan, Korea, and parts of the United States
One family in Lower Allen Township, Pennsylvania, complained that when they opened kitchen cabinets, the bugs were sitting in their dishes. They found them waiting inside drawers and under the bed and crawling through the attic by the hundreds. And when Christmas came, the bugs climbed up the family’s tree and took their place among the ornaments.
The husband, who suffers from obsessive compulsive disorder, couldn’t stand the sight of the bugs. He stretched duct tape a
round his windows, but they kept coming back. Even going to work offered no respite: as a mailman, he found them in mailboxes all day long.
What makes these home invaders so intolerable is their smell. It is difficult to describe the odor of a stink bug; some people characterize it as a rotten fruit smell, a combination of cherries and grass, or a moldy, musky almond fragrance. Most people simply call it a foul, heinous odor that they’ll never forget. Disturbing the bugs, stepping on them, or vacuuming them up — the control method recommended by experts — releases the stink, which in turn can function as a kind of signal to attract more stink bugs to the home. In large quantities, some species have even created traffic hazards: in 1905, newly installed electrical lights drew so many stink bugs to intersections in Phoenix that street cars couldn’t plough through the piles of bugs massed on the ground.
When Christmas came, the bugs climbed up the family’s tree and took their place among the ornaments.
The brown marmorated stink bug was probably introduced to Pennsylvania by accident in the late 1990s. Like other stink bugs or shield insects in the Pentatomidae family, these wide, flat insects look like a shield when viewed from above. Their defensive secretions contain cyanide, which explains the bitter almond smell. And while stink bugs are generally harmless, inflicting only minimal damage to plants, this Asian invader is being watched closely as it has the potential to become a pest of fruit trees, soybeans, and other crops. After establishing itself in Pennsylvania, it moved into New Jersey and then showed up across the country in Oregon. It has now been seen in twenty-seven states.
While its damage to plants has been mild so far, the stink bug is universally despised as an indoor pest. It crawls around in closets, requiring people to shake out their clothes before getting dressed. Women find the bugs crawling in their hair. They creep in through window-mounted air conditioning units, making it necessary to remove the units or seal them completely during winter months. While pyrethroid insecticides sprayed around a home’s exterior in the fall might keep them out, they are of little use against the bugs indoors and may pose more health hazards than the bugs themselves. Vacuuming up the bugs does work, but the stink is so powerful that most people buy a separate vacuum cleaner just for bug removal.
One small comfort is that the bugs don’t breed in the winter, so they don’t start new families indoors. Once spring arrives, the adults leave of their own accord to return to gardens and fields, where they will mate and lay eggs. The eggs hatch in late summer, and the nymphs go through five stages of molting before reaching adulthood. This new generation then goes in search of a place to spend the winter, settling indoors by October, just as their parents did.
Meet the Relatives Stink bugs are a large and diverse family found in Australia, North America, Europe, Asia, Africa, and South America. Relations include the leaf-footed bugs, which feed on a wide variety of plants.
PAINFUL
Brown Recluse
LOXOSCELES RECLUSA
Ah, the poor, misunderstood brown recluse. This un-assuming spider gets blamed for every kind of pustule, boil, and eruption that might afflict a person. According to reports in medical journals, the brown recluse has been held responsible for staphylococcus infections, herpes, shingles, lymphoma, diabetes-related ulcers, chemical burns, and even allergic reactions to prescription medications. Arachnologists insist that there are only two ways to accurately diagnose a brown recluse bite: to either capture the spider in the act and get it identified or have a dermatologist biopsy a fresh bite wound. Without that evidence, it is entirely likely that the painful, rotting lesion that sends a person running to the doctor was caused by something other than this dreaded spider — and the misdiagnosis is often more deadly than the spider bite itself.
SIZE:
Up to 9.5 mm
FAMILY:
Sicariidae
HABITAT:
Dry, sheltered, undisturbed places like woodpiles, sheds and undergrowth
DISTRIBUTION:
Central and southern United States
That’s not to say that the brown recluse doesn’t bite, or that its bite isn’t painful. A severe brown recluse bite manifests itself as a nasty, swollen skin ulcer with dead tissue in the center. These bites form a red, white, and blue bulls-eye pattern, with a painful red area around the edge, then a white circle where blood flow is restricted, then a bluish-gray spot in the center that represents dying flesh. Contrary to rumors, most people recover from these wounds quickly, with only the more severe cases lasting a month or two. While there have been news reports of deaths caused by brown recluse bites, these accounts are disputed by some of the nation’s leading brown recluse experts.
A Kansas family collected over two thousand brown recluse spiders in and around their home. Remarkably, no one was bitten.
What accounts for the number of misdiagnosed brown recluse bites? The spider itself was virtually unknown until the second half of the twentieth century, when a handful of news accounts placed the blame for mysterious wounds with this little-known spider. Now it seems that every person with an unexplained sore is able to find a small brown spider nearby. The brown recluse is easily confused with other species: similar arachnids resemble it and several even have the same violin-shaped marking on the back. The only way to accurately identify a brown recluse is to look deep into its eyes: they have six of them, arranged in three pairs. Experts also look for a uniformly brown abdomen covered in fine hairs; brown, smooth legs; and a small size (the body no more than nine and a half millimeters long).
Spiders in the genus Loxosceles are found in central and southern areas of the United States, but reports of their bites persist nationwide. To date, L. reclusa has only been positively identified in sixteen states: Texas, Oklahoma, Kansas, Missouri, Arkansas, Louisiana, Mississippi, Alabama, Tennessee, Kentucky, and parts of neighboring states, including Nebraska, Iowa, Illinois, Indiana, Ohio, and Georgia. A few other species, including L. deserta, arizonica, apachea, blanda, and devia, have been found along the Mexico border through Texas, New Mexico, Arizona, and inland portions of southern California, but none of these are the true brown recluse.
Reports of the spider in other parts of the country are so persistent that frustrated arachnologists have offered rewards to anyone who could send them an actual brown recluse from an area where they are not known to live. One California scientist called it the “Show Me the Spider” challenge. After years of attempting to locate a brown recluse in the state, University of California entomologists have declared that the brown recluse definitively does not live in California.
For people who do live in places where the spider is found, it can be disturbing to realize how many of them live nearby. A family in Kansas collected over two thousand brown recluse spiders in and around their home in just six months. Remarkably, no one was bitten in the six years they lived in the house. A recluse usually won’t bite unless it is quite literally forced against the skin. For this reason, the best advice experts can offer is to shake out camping gear, as well as bedding or clothing that’s been in storage or crumpled on the floor for a long period of time. Avoid the recluse, they say, and the recluse will avoid you.
Meet the Relatives Recluse spiders are related to another genus of six-eyed spiders called the six-eyed sand spider. These spiders are known for their necrotic venom.
DANGEROUS
Chigger Mite
LEPTOTROMBIDIUM SP.
Soldiers fighting in World War II had to face down more than the enemy. In Burma, monsoon weather, unfamiliar terrain, and exotic diseases made for a deadly combination. Virtually every soldier in the area was hospitalized at some point during 1944. Although combat was heavy, soldiers were nineteen times more likely to die from disease than from battle wounds. Hepatitis, malaria, dysentery, and venereal diseases posed serious problems, but perhaps the most challenging disease was the unfamiliar and unpredictable scrub typhus, transmitted by a tiny arachnid known as a chigger mite.
SIZE:
0.4 mm
FAMILY:
Trombiculidae
HABITAT:
Low-lying, damp grasslands and woodlands
DISTRIBUTION:
Throughout Asia and Australia
The chigger, actually the larval form of a mite in the genus Leptotrombidium, is a minute creature that feeds on blood only once in its life. It is so small that its mouth can’t even penetrate the skin deeply enough to hit a blood vessel; for this reason it simply bites into the skin and drinks down a kind of liquefied beverage of skin tissue and blood. A person might not even feel the bite until later, when a little redness develops at the site. This is usually caused by the chigger leaving its feeding tube behind, which can irritate the skin the way a tiny splinter would. Once the chigger has enjoyed its one and only blood meal, it matures into an adult mite and feeds only on plants for the rest of its life.
One Army medical expert predicted that all of his patients infected with scrub typhus would live with permanent heart damage.
How, then, is the chigger mite able to transmit disease? If it only feeds once, there is no opportunity to take up the infection from one host and pass it on to another. Scientists solved this mystery when they were able to prove in the laboratory that these mites are capable of transovarial transmission. In other words, adult chiggers who get infected during their one blood meal then pass the infection on to their offspring. For that reason, a young chigger might already be infected from birth, and pass the infection on when it takes its first and only blood meal.
Scrub typhus, also called tsutsugamushi fever, is found in populations of wild rats, voles, mice, birds, and also in humans. People who have been infected with the Orientia tsutsugamushi bacteria usually experience flu-like symptoms after about ten days, including muscle aches, swollen lymph nodes, fever, and loss of appetite. Eventually, the disease can move into the heart, lungs, and kidneys, resulting in death if antibiotics and other life-saving treatments are not administered in time. Up to a third of people who don’t get treatment will die from the disease.