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Kells, an assistant professor of entomology, is one of a handful of researchers around the country studying bedbugs, spurred by a resurgence in infestations of the tiny bloodsucking parasite.
His ultimate goal is to develop a trap that can effectively monitor the presence of the pests. However, bedbugs are secretive, elusive and hard to kill, and they frequently defy efforts by pest-control companies to learn whether they’ve been eliminated from an infestation site.
“There is no monitoring device for bedbugs. That would be absolutely innovative. Huge,” said Greg Grabow, a national sales manager with Temp-Air, a Burnsville company getting into the bedbug-control business.
Some property owners have resorted to hiring expensive, specially trained dogs to sniff out bedbug hiding places. But dogs won’t necessarily be able to find bedbugs lurking near the ceiling.
Build a better bedbug trap, and hotel chains, property managers and pest-control companies will beat a path to your door, Grabow said.
Alas, “we’re quite a distance off” from a monitoring trap, Kells said.
First, scientists have to figure out what makes the cryptic, fast-moving, hungry Cimex lectularius tick, said Kells, 40.
“There’s a lot of stuff that’s unknown,” he said. “We have a blank slate. We have an insect that’s not been studied for 30 years.” For years, researchers ignored bedbugs, Kells said, because the insects had been largely eliminated from developed countries thanks to the widespread use of long-acting pesticides such as DDT. From the 1970s on, “they virtually disappeared,” he said.
Bedbugs almost assumed the status of a mythical creature, said Harold Harlan, a former Army entomologist. A researcher once asked him whether bedbugs actually existed.
“We had a whole generation of entomologists that never saw a bedbug,” Kells said.
In the late 1990s, however, bedbugs — reddish-brown oval insects that grow to about the size of an apple seed — re-emerged. Infestations began to be reported in hotels and houses, where the pests fed on unsuspecting victims as they slept, requiring eradication efforts that cost hundreds and even thousands of dollars per location.
Experts theorize that bans on DDT and other insecticides, and increased international travel led to the bedbug renaissance.
Kells first encountered a bedbug in about 2000 while working in the pest-control industry in Canada.
He dipped it into insecticide. The beast lived for four days and laid eggs.
“At that point, I knew we were in trouble,” he said.
Kells decided to study the insects further in an academic setting. He came to the University of Minnesota 3½ years ago and set up a lab devoted to bedbug research.
About 2,000 bedbugs live there, housed in jars, where they crawl around pieces of filter paper that vibrate and twitch with their constant motion.
They eat Red Cross-donated human blood that’s beyond the expiration date, heated to body temperature.
Kells built a special platform he calls a bedbug arena, where he can observe the behavior of individuals when exposed to stimuli like heat. Part of his research is funded by the Propane Education Research Council, which wants to know whether propane-heaters can be used to kill the insects.
Another set of experiments involves attaching bedbug antennae to tiny electrical probes to see what kind of chemical compounds the antennae are tuned to receive. This might help develop the lure — maybe the carbon dioxide that sleeping humans exhale or the fatty acids on our skin — for a bedbug monitoring trap.
Here’s some of what Kells can tell you about bedbugs:
They have a painless bite, the better to keep you undisturbed while they feed. Afterward, you can get itchy welts from their bites. But bedbugs haven’t been shown to spread disease.
“They’re very hardy,” Kells said. “They’re very tough to kill. But they can be killed.”
Heat will kill them, but you have to cook them to 120 degrees.
Cold will kill them. Kells recommends chilling bugs down to minus 10 for 10 days to two weeks to be sure. A British company has developed a minus 108-degree carbon dioxide spray that is supposed to do the trick.
Kells has deprived them of oxygen for up to 24 hours. They’ll still live.
“I think it’s an offshoot of their lives in caves,” Kells said of the prehistoric time when bedbugs first moved from feeding on bats to feeding on cavemen.
It’s hard to starve them. Bedbugs have been known to survive up to a year without eating.
“These bugs have an ability to conserve water that’s equal to a desert insect,” Kells said.
Bedbugs stink.
“They’re very aromatic. They have a lot of chemicals that come off their bodies,” Kells said, sticking his nose into a jar and taking a sniff. “It smells like dirty socks.”
Simple soap and water or bleach or alcohol will kill a bedbug on contact, but you can’t put a whole bedroom or hotel room into a washing machine. And it can be hard to find all the bedbugs hiding in a room.
In a typical infestation, most bedbugs will cluster in the seams and crevices around a bed, but maybe 10 percent or 20 percent are often found some distance away, hiding in computer equipment or in the ceiling smoke detector or flattened between a picture and the glass in a picture frame, Kells said.
He said he doesn’t know why some bedbugs wander away from the main group. Maybe they’re females trying to escape “traumatic insemination.” That’s the bedbug male mating practice of injecting sperm by puncturing the body wall of the female. More than six matings starts to kill the female, Kells said.
Social class doesn’t seem to matter to bedbugs. They’ll infest hostels as well as five-star hotels, researchers say.
Bedbugs are a lot more resistant to poisons than they used to be. It takes 1,200 times the amount of insecticide to kill recently captured bedbugs than it takes to kill individuals from bedbug colonies that have been in captivity for more than 30 years, Kells said.
That captive colony was maintained by Harlan, who collected about 600 individuals from a barracks at Fort Dix, N.J., in the early 1970s. They were a novelty at the time, Harlan said. Over the years, he kept the colony alive in jars, letting it grow into the thousands, by allowing the bugs to feed on his legs.
“I’ve had them escape a few times in my house,” he said.
He had to leave the colony untended for a year when he was deployed in Vietnam and couldn’t find anyone willing to be a food source. When he came home, enough had survived to rebuild the population. Now his pets have become a resource for researchers.
“They’re very adaptable,” Harlan said. “They’re a little gluttonous and a little oversexed. Maybe you are what you eat.”
