Of all the disturbing things about bedbugs, their mating habits may be the worst. Cimex lectularius have evolved a breeding technique called "traumatic insemination," and it's even more horrible than it sounds.

A male bedbug's penis is literally a weapon—a sharp, brown hypodermic hook that forgot about the female reproductive canal long ago. Here's how he uses it: The male pounces on the female, holds her firmly while she struggles, and gouges his hook through her exoskeleton, squirting his sperm directly into her body cavity. The sperm swims through her hemolymph (a bug's version of blood) and, if the mating wound doesn't develop a serious infection and kill her, eventually swims to her ovaries.

Biologists used to believe males and females of a given species evolved together for sexual fitness, the Darwinian version of romance. But bedbugs, scientists have found, have engaged in a millennia-long struggle of "sexually antagonistic coevolution" in which individual males damage individual females for overall reproductive advantage. Female bedbugs have counterevolved "spermalege," a special sperm-receptacle organ in the abdomen that helps absorb the trauma—if the hypodermic penis hits it. Bedbugs aren't exactly careful maters. Male bugs sometimes traumatically inseminate each other, though scientists aren't sure whether this is a function of sexual competition or just carelessness. Regardless, sex is bad for female bedbugs. A 2003 study for the Royal Society of London found that the more sex a female bedbug has, the shorter her life will be.

A bed infested with bedbugs isn't just a party for bloodsuckers that will make you itch—it's also a Verdun of buggy sexual warfare.

This past summer, Lauren Hester began to itch. Then she noticed red welts in little rows all over her skin. She was living with her boyfriend, Andrew Lazarow, both of them theater artists and members of Seattle company the Satori Group. But after weeks of hearing his girlfriend complain about the itching, Lazarow still didn't believe it had anything to do with their First Hill apartment: "I thought it was mosquitoes or something." Lazarow is a small, earnest man with brown stubble and black-framed glasses, and he has a pained expression as he recalls this part of the story. "I still feel really badly," he says. "I wasn't getting bitten and I was dismissive."

But Hester's bite patterns were textbook. Bedbugs bite in rows for three reasons. First, they are extremely sensitive to movement. If a sleeper twitches at night, the bugs stop feeding, take a few lateral steps, wait for stillness, and start sucking blood again. Second, the rows can be the result of bedbugs searching for a vein to drill into. Third, according to Bedbugcentral.com, several bugs might be lined up along a fold or overlock on a sheet, "all feeding at the same time, similar to cattle at a trough." Either Lazarow wasn't getting bitten or he wasn't feeling it—people react differently to the bites. (Bedbugs feed by injecting two hollow tubes into their hosts. One tube injects saliva with anesthetics and anticoagulants, the other sucks out the blood. People who get itchy from the bites are having a reaction to the bedbugs' spit.)

One night, after training with the Satori Group, Hester insisted they check the apartment for bedbugs. (Another company member, Spike Friedman, had experienced a horrible bedbug infestation when he lived in Manhattan.) To make her happy, Lazarow scrutinized the mattress and pillows—and found little black dots, the scat bedbugs leave behind on their postprandial walk home. They lifted the mattress and saw more black dots, plus a few bugs scurrying away. "I freaked out," Lazarow says. "You could see their feces of our blood. I'm a little OCD and germaphobic: These things are defecating on my pillow! Are there some in my mouth?"

At the height of the six-week ordeal that followed, Lazarow says, "I'd wake up at two in the morning every night, lying there sleepless, knowing they were about to come out."

Lazarow and Hester ran some clothes through the dryer—heat is one of the few things that can kill bedbugs—and then went directly to the Sorrento Hotel. "They were incredibly gracious," Lazarow said. The couple explained what was happening, and the hotel cut them a deal. The next day, Hester and Lazarow called the extermination company Paratex ("I can't recommend them highly enough"). They stuffed everything they owned into a U-Haul to take to Paratex to be put into a big, vacuum-sealed tube for 24 hours of fumigation.

"We loaded everything except for some clothes," Lazarow says. "Literally everything else. When my friend Spike had his infestation, he saw bedbugs crawling out of his laptop, out of his iPod." Then back to the apartment to live out of Ziploc bags for six weeks and wash their bedding every day before a second round of fumigation and spraying.

Between the treatment, four nights at the hotel, and the laundry bills, the couple spent over $1,500. Afterward, they weren't convinced the apartment was fully clean. So they moved out.

Bedbugs hide wherever they can—box springs are good, as are walls, chairs, even suitcases—and, if they go dormant, can survive up to 18 months between meals. Leaving a room and starving them out is not a viable option. Bedbugs tend not to travel more than 100 feet from their host but can migrate easily between apartments if they choose, especially along boards and pipes. Clay Thompson, of Seattle's Department of Planning and Development (DPD), says the best way to deal with an infested apartment is to treat all the proximal apartments, too: left and right, above and below. But landlords and tenants are reluctant to pay for what they perceive as prophylactic measures. "Bedbugs are," Thompson says with a note of finality in his voice, "definitely hard to get rid of."

In Seattle, Thompson says, bedbugs are on their way to becoming a "crisis." During his first 22 years with the DPD, he had only heard a handful of bedbug complaints. But in the past year, the complaints soared, the majority coming in the past two or three months. "The curve has been very steep," he says. "When we first started hearing about them, we didn't even know what to look for. So we had some enterprising inspectors who went to the web and got a photograph to see what they looked like."

The earliest reports of the bedbugs' return came out of New York City: In 2004, the city information line 311 received fewer than 100 calls about bedbugs. In 2006, it received over 4,600 calls. In 2008, over 9,000 people called. This year, Bill Clinton and his staff had to vacate their offices in Harlem for a bedbug infestation, which kicked off the predictable jokes about Clinton keeping a bed in his office. But the bugs are invading other people's offices. The New York offices of Penguin press had an infestation this year; last year, a bedbug problem at Fox News ended in a lawsuit, when one of its employees claimed she was suffering PTSD after being bitten three times. This past September, advertising firm Saatchi & Saatchi—most famous for its campaign for the UK's conservative party, "Labour isn't working"—had to fumigate its 17th floor.

And the bedbug invasion has expanded. Toronto Public Health has reported that it handled 1,500 infestations in 2009, up from 46 in 2003. The website Torontoist held a vote for the city's Supervillain of 2009. Out of 24 contestants, bedbugs won third place.

Blame the bats. Biologists theorize bat caves were the parasites' original breeding ground; then when early humans moved in, they dropped down and started feasting on us. From the cavemen until the late 20th century, bedbugs—and their big red welts—were just a fact of human existence, one of the unhappy nuisances of being a person. That ended around WWII, when powerful pesticides like DDT knocked bedbugs—in wealthy countries, at least—into oblivion.

DDT also knocked bird populations onto endangered-species lists and was correlated with human cancers. "It all started with the lady named Rachel Carson and her book called Silent Spring," says Jim Osborn, the no-nonsense but friendly president of Seattle's 102-year-old Paratex pest control. (Osborn used to get a couple of calls about bedbugs a year. Now he's getting queries almost every day.) "DDT should have been vastly curtailed, but not banned. It's a wonderful chemical that should have been restricted to limited circumstances for limited use. But the pendulum always swings from one side to the other. It defies common sense, but that's how the world works."

Silent Spring successfully led the charge to dramatically curtail the use of pesticides like DDT.

And bedbugs are back.

It's been so long since we've seen bedbugs, even inspectors have forgotten what they look like. And some people who should know better have forgotten they even exist. "It has shocked me," says Jeff White, a research entomologist at New Jersey–based business Bedbugcentral.com. "I've been on the floor of trade shows of industries where bedbugs should be a major concern—assisted living, for example—and have had people tell me they thought bedbugs were just a nursery rhyme: 'Sleep tight, don't let the bedbugs bite.'"

But it's been decades since the U.S. banned DDT and other potent pesticides. Why are bedbugs only just now staging their comeback?

Nobody knows: not White, not Thompson, not the half-dozen other people I asked while working on this story. But pretty much everyone trots out the same not entirely satisfying theories: increased international travel, cross-contamination from industrial chicken farms (though they prefer people, bedbugs can live off of chickens, which have been the cause of major infestations), and the increase in swapping used furniture thanks to Craigslist. (Get people murdered, put newspaper classified sections out of business, encourage epidemics—is there anything Craigslist can't do?) And maybe the old poisons were more powerful and prevalent than we thought.

"DDT was a powerful residual pesticide," says White of Bedbugcentral.com. "You apply DDT to a baseboard and if a bedbug walks across it years later, it'll die. And just because DDT was banned in the 1970s doesn't mean people stopped using it in the '70s. People had old stores of the pesticide they were using up. That takes time."

If White's theories are true, we are only just now beginning to live in a DDT-free world. And it looks buggy.

In the absence of DDT, exterminators use a constellation of other methods to kill bedbugs: liquid, gas, earth, and fire. The four elements. It's like medieval magic.

The liquid and gas methods are about what you'd expect: pesticide sprays and fumigation, either sealing off a building in a plastic tent, E.T.-style (expensive), or removing everything from the building and shoving it into a vacuum-sealed tube for fumigation (not quite as expensive).

The fire method: Bedbugs can't live at very high temperatures, so exterminators will sometimes bring in high-powered space heaters and push the room temperature up past 120 degrees Fahrenheit for several hours. (A cheaper, slightly less reliable version recommended for travelers returning with plastic bags full of contaminated clothes: seal them up in a car full of summer sunlight for a full day.) But the heat can't always penetrate to the center of a mattress, where the bedbugs live, and isn't always effective.

And the earth method: diatomaceous earth, a fine, chalklike dust made of fossilized, hard-shelled algae called diatoms. Diatomaceous earth is abrasive and super-absorbent. People use it for hydroponics, high-drainage soil, cleanup of toxic spills, cat litter, thermal insulation, a blood coagulant, and a mechanical (rather than chemical) insecticide. The fossil dust (33 to 86 percent silica, 5 percent sodium, other percent other stuff) sucks the waxy lipids out of a bedbug's exoskeleton, turning all that human blood in its guts into a scab and causing it to die of dehydration.

Finding their crispy, desiccated corpses—several people have posted pictures to bedbug internet threads—is very satisfying.

Bedbugs aren't dangerous. They're not a vector for disease like mosquitoes and fleas—something of a mystery, as they have all the prerequisites for passing blood-borne disease from one host to another—but they're annoying and gross and they freak people out. Friends have told me stories about unscrupulous exterminators preying on their hysteria, and bedbug-specific websites are springing up around the world. Maciej Ceglowski runs a civic-minded site based in Romania called Bedbugregistry.com, where people post reports of bedbugs in office buildings, apartment complexes, and hotels. (Some are surprising: the Four Seasons in San Francisco, Disney's Old Key West Resort, the unfortunately named "Yosemite Bug Rustic Mountain Resort.")

Ceglowski started the site after having an unpleasant encounter with bedbugs in San Francisco in 2006. He'd just moved back from Beijing and was staying in "a dingy Travelodge on the corner of Valencia and Market streets. I had a song in my throat, a dream in my heart, and... I was about to discover that I also had a sizable bedbug colony under my mattress." This discovery led to a lifetime obsession and Bedbugregistry.com, which is not only a place where travelers warn each other about bedbugs but a kind of support group where people post angry rants, pathos-laden cris de coeur, and gallows humor—all the shock, angst, and wry fatalism of the contemporary infested.

Ceglowski's mother grew up in Lodz, Poland, when bedbugs were just a fact of life. When moving into a new place, Ceglowski wrote, "One of the first things she would do was check behind picture frames and in the cracks in wallpaper for bedbugs. They were quite common but considered a sign of a lower-class place." In those pre-DDT days, Ceglowski writes, "There were lots of techniques for avoiding bedbugs in infested places. Putting bedstead legs in cans of kerosene or water was common (bedbugs defeat this ploy by climbing onto the ceiling and dropping when they feel the heat of a host below). If things got bad enough, you might sleep in the tub."

Bedbugregistry.com shows only a few reports in Seattle (including the Green Tortoise Hostel downtown and the Renaissance hotel on Madison, in case you're wondering—neither of them returned requests for comment), but Ceglowski says he's getting around 15 reports a day from New York, Toronto, San Francisco, and Vancouver, where people are starting to worry about bedbugs at the Olympics. Canadian newspaper editorials wring their hands about visitors infesting their city—it was a problem for Sydney in 2000—but at the rate Vancouver infestations are going, they should be more concerned about becoming a major export center broadcasting bedbugs across the world.

Bedbugs have been a source of controversy at Seattle Housing Authority (SHA), which provides low-income apartments to over 26,000 Seattle residents. Bedbugs have moved into SHA units—especially the Denny Terrace building and Bell Tower—and some residents feel like the city isn't responding quickly enough to stanch the infestation. Virginia Felton, who has worked at SHA for 10 years, heard the first reports of bedbugs this year at Denny Terrace. Over a third of its units have been treated for bedbugs so far, with 35 outstanding work orders. The waiting list just to have your apartment inspected is two weeks. (SHA acquired a bedbug-sniffing dog—a young female black lab with the nickname "Bugsy"—to help combat the problem. The dog was adopted by a trainer in Florida about two days before being put down and, according to Felton, cost SHA around $7,000.)

Kenneth Jennings, chair of the resident council for Bell Tower, says the wait is too long—not just for residents, but for the city: "If this problem is not properly addressed soon, Seattle may be in for a wider epidemic of these pests that will impact well beyond the confines of low-income housing."

Julie Wade, a pro bono attorney for the resident council, thinks those numbers might even be underreported. "People are reluctant to complain," she says. "They're worried about losing their housing and worried about retaliation."

Wade, currently a director of corporate counsel at Starbucks, worked as an attorney for SHA for many years, but now negotiates with SHA on behalf of its clients. "I worked inside the organization for years and have a tremendous amount of respect for what SHA does," Wade says. "But they make mistakes, and sometimes there's the attitude that arises—I hate to say it, because it's not an easy job—but that beggars can't be choosers. That they should be able to put up with a little inconvenience."

Wade first came on the bedbug case during a meeting with clients she thought was going to be about some renovations that were disrupting residents. (SHA had been drilling into concrete for three weeks at a time and had cut the water 22 times in the last three months. The construction was, in Wade's terms, disrupting SHA's ability to "provide a clean, safe, sanitary environment and provide a quiet enjoyment of the premises.") She met with residents at Bell Tower to talk about the renovations—she thought—and to get them a break on their rent. But everyone wanted to talk about bedbugs.

"SHA isn't ignoring the problem, but their response is inadequate," Wade says. "They send inspectors who don't seem to know what they're looking for, and they need to respond quicker than two weeks. There are special challenges with buildings and populations like this, but all I know is people are suffering."

"If SHA isn't more aggressive," Wade says, "these bedbugs may be everywhere."

That could be. Both Felton at SHA and Thompson of the DPD admit the city doesn't have the resources to exterminate its bedbugs. "We could spend thousands and thousands of dollars getting rid of the bedbugs in any given place," Felton says, "and then someone could just bring them back in."

So what does she propose?

"If we can provide resources for our residents to not be bitten constantly and get a good night's sleep, then that's pretty good."

In other words, bedbugs are now a permanent fact of life for the urban poor in Seattle, just like the old days. And SHA isn't trying to exterminate the bedbugs, just keep them out of the bed?

"Yes."

How?

"Provide bed frames for our residents to get their mattresses off the floor, tell them to keep the beds away from the walls and their blankets off the floor," she says. "And there are these little interceptor disks you put beneath the legs of the bed..."

It seems like I've heard about this technology before—the pots of kerosene Ceglowski's mother used in Soviet-era Poland.

Have a question about bedbugs? Brendan Kiley and other bug experts will be taking readers' questions in Questionland!

This article has been updated since its original publication.