This story was upated August 9, 2013
Bed bugs – those tiny predators that feed at night on their slumbering human hosts and then scurry to safety in mattress seams, wall cracks and baseboards – have proved both difficult to find and exterminate.
Changlu Wang, an assistant extension specialist at the School of Environmental and Biological Sciences, is studying their feeding habits and dispersing patterns, while he also devises new ways to capture and kill them.
A few decades ago there was little reason to study bed bugs, as the potent, all-purpose pesticide DDT simply wiped them out. But they are proliferating in the wake of its ban, particularly in the urban Northeast. Enormously adaptable, they 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,” said Wang, who recalled the time he found 1,300 bugs in a single trap he had set overnight in an apartment in Bayonne.
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 said. Indeed, residents of Plum Street in New Brunswick have been battling bed bugs this fall, jettisoning mattresses and couches in frustration.“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,” said Vincenzo Averello, a former student who found the bed bug project by way of the Aresty Research Center for Undergraduates Summer Science Research Program this past summer.
“The other thing that fascinates me is how resilient they are. They can survive for so long and on so little,” Averello added, noting that his primary research interest is to “look at a species at population-scale, to see how it is affected over time by changes in the environment.”
Bed bugs locate their hosts by sensing their most fundamental emanations. Wang and his research colleagues are exploiting this behavior to catch them. They recently developed a do-it-yourself trap that can alert homeowners to infestations at their early stages, when bed bugs are more easily exterminated.
“They are attracted by heat and carbon dioxide. They are attracted to your breath,” said Wang, who has created an inexpensive trap based on a modified dog bowl and a carbon dioxide source. “The carbon dioxide attracts 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.
Wang grew up in a farming village in China, and, as Averello, developed a keen interest in bugs as a child.
“As an 8 year old, I would go into the forest to look for cicada nymph. They live in small holes in the ground and you need a good eye to find them,” Wang said. He also looked on helplessly at times as a swarm of grasshoppers wiped out a crop in one day.
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 said. 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 bed bugs 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 said.