PITTSBURGH (Associated Press) - Bedbugs aren't just sleeping
with you. They're sleeping with each other.
Researchers now say that the creepy bugs have a special genetic
gift: withstanding incest.
It turns out that
unlike most creatures, bedbugs are able to inbreed with close
relatives and still produce generally healthy offspring. That means
that if just a few bedbugs survive in a building after treatment,
they repopulate quickly.
Coby Schal and Ed Vargo are entomologists at North Carolina
State University, and they presented preliminary research on
genetic diversity in bedbug populations on Tuesday in Philadelphia,
at the annual meeting of the American Society of Tropical Medicine
"We kept discovering the same thing. Within a given apartment,
or even a given building, there was extremely low genetic
diversity," said Schal. "In most cases there's just a single female
that founded the population."
Schal said that was a surprise, since an animal or insect
population with limited diversity will usually build up and then
crash, because genetic defects tend to magnify with inbreeding.
"But somehow bedbugs are able to able to withstand the effects
of inbreeding, and do quite well," he said.
The new research is important, said Zachary Adelman, an
entomologist at Virginia Tech University who wasn't part of the
North Carolina State team.
"No one had looked at these things," he said of the genetic
makeup of bedbugs. "It's pretty exciting."
And pretty depressing.
The researchers also found that while the community within a
building tends to be similar, there are many different strains of
bedbugs throughout the East Coast, suggesting that new colonies
also get introduced through foreign travel or commerce.
"That means they're coming into the country from lots of
different places," which means that the bedbug problem isn't going
to stop anytime soon, said Adelman.
The findings may also help explain another part of the bedbug
Bedbugs - and other insects - develop resistance to
insecticides. Schal said that if a treatment kills anything less
than 100 percent of the bugs, the survivors will not only
repopulate, but pass on the resistance they've developed to future
"The insecticides really need to be robust" to do the job, Schal
Bedbugs are wingless, reddish-brown insects that bite people and
animals to draw blood for their meals. Though their bites can cause
itching and welts, they are not known to spread disease.
Another researcher notes that you have to discover a problem
before you can treat it.
Rajeev Vaidyanathan of SRI International, a nonprofit research
firm with headquarters in Silicon Valley, said he's working on a
quick, easy test so people can discover bedbugs before they get
Vaidyanathan said current technology comes down to spotting live
or dead bedbugs, or using dogs to sniff them out.
"Both are often ineffective and tedious," he said.
So Vaidyanathan is trying to developing a biochemical test to
identify bedbug-specific proteins that they leave behind, even when
only a few bugs are present. Homeowners would swab a section of
their home, and dip it in a special compound.
"A home pregnancy kit type of read-out. If there's a color
change, you have a bug," he said, but it's too early to say when or
if the idea will make it to market.
Vaidyanathan also pointed out some other forces behind the
spread of bedbugs.
"The problems we are seeing with bedbugs in North America did
not happen overnight," said Vaidyanathan. "We have the highest
concentration in the history of our species of humans living in
cities. Bedbugs do not have wings; they are nest parasites, so our
own population density has helped them to thrive."