RUTGERS (US)—Changlu Wang and his team are studying the habits of blood-sucking bedbugs in an effort to identify novel ways to capture and kill them. Ignored by researchers for decades, bedbugs are proliferating in the wake of a ban on the pesticide DDT.
Enormously adaptable, bedbugs are resistant to most commercially available pesticides.
“I predict they will stay a long, long time. No other pesticide does the job that DDT does,” says Wang, an assistant extension specialist at Rutgers School of Environmental and Biological Sciences. He recalls the time he found 1,300 bugs in a single trap he had set overnight in an apartment in Bayonne, N.J.
He is working with researchers at Rutgers and other universities to develop integrated methods to capture and exterminate them that won’t wreak widespread environmental damage. These include encasing mattresses, applying hot steam, placing interceptors under the legs of furniture so they can’t reach their hosts, and devising traps that will lure and kill them.
In the absence of effective controls and decontamination methods, “the typical practice is to spray chemicals or throw away expensive clothes, electronics, and books,” Wang says.
“What’s interesting to me is how the population came back. They had been taken care of, and now we have to figure out how to deal with them again,” says undergraduate researcher Vincenzo Averello.
“The other thing that fascinates me is how resilient they are. They can survive for so long and on so little,” Averello adds.
In the current round of experiments, his first task is to grow thriving populations of bedbugs in small, mesh-covered jars. So they will increase quickly, he is treating them to weekly half-hour feedings on lab guinea pigs, which they reach through the mesh covering their jar top but can’t escape through. The guinea pigs are unharmed.
Bedbugs locate their hosts by sensing their most fundamental emanations. Wang and his research colleagues are exploiting this behavior to catch them.
“They are attracted by heat and carbon dioxide. They are attracted to your breath,” says Wang, who has created an inexpensive trap based on a modified double-bowl cat feeder. The trap contains dry ice, which emits carbon dioxide to attract the bugs, which then fall into the feeder and can’t escape. Wang will be experimenting to see whether the addition of heat increases the trap’s allure. He has also filed a patent for an intercepting device that is placed under furniture.
The compound that attracts bedbugs also kills them at high doses. Wang and Averello will test the lethality of various carbon dioxide concentrations and exposure times.
As entomologists play catch-up with the bedbug, which evolved from cave-dwelling bat bugs, they are still grappling with several unknowns.
“One of the things we still don’t know about bedbugs is why and when they disperse, or how far they travel,” Wang explains. He and collaborators from Purdue University have applied for a grant from the U.S. Department of Housing and Urban Development to monitor them and test control measures in a high-rise building in Indianapolis.
But Wang doesn’t find them very interesting.
“Cockroaches and bedbugs are of no use. They are pests completely. They congregate, because it’s easier to find mates that way, but unlike the ant, they have no interesting social behaviors,” he adds.
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