Posted on 10/23/2011 7:15:22 AM PDT by PJ-Comix
Until about a decade ago, most people in the United States only knew about bedbugs through the seemingly dated phrase "Sleep tight, don’t let the bedbugs bite." But the bloodsucking parasites, which were largely eradicated by the mid-20th century, have roared back in all 50 states, and the bugs’ evolving resistance to insecticides is part of the reason for their resurgence. A new study gives the most complete picture so far of the adaptations some bedbugs have developed to thwart exterminators’ poisons.
The pesky bugs, it appears, can pump out a stew of enzymes that destroy insecticides, according to the study out this week in the journal PLoS ONE. This newly described neutralizing mechanism is in addition to a mutation, which scientists revealed a few years ago, that alters the structure of bedbugs’ nerve endings and prevents common insecticides from binding to their nerves. Together, these defenses could form a one-two punch that protects bedbugs from exterminators’ chemicals.
"The enzymes we discovered in the context of this paper are essentially the initial line of defense in breaking insecticide down before it reaches the nerve," Zach Adelman, lead author of the paper and an associate professor of entomology at Virginia Tech, says.
To figure out bedbugs’ defenses, Adelman and colleagues started by gathering a sample of bedbugs from Richmond, Va. The Richmond bugs had demonstrated strong resistance to a class of insecticides known as pyrethroids—the agents of choice for exterminators. Pyrethroids paralyze bedbugs by keeping open the sodium channels where nerves meet and communicate with one another. "The nerve will keep firing, and it can’t relax," Adelman explains. The result: paralysis and eventual death.
The researchers also used some bedbugs that had been reared in a lab in Fort Dix, N.J., for decades, and had not been exposed to chemicals. When Adelman’s team blasted both sets of bedbugs with two different pyrethroid insecticides—one called beta-cyfluthrin and another deltamethrin—they found that the Richmond bugs could withstand 111 times the dose of the beta-cyfluthrin insecticide compared with the Fort Dix bugs, and a whopping 5200 times the dose of deltamethrin.
Clearly, the hearty Richmond bugs had adapted some strong defenses. Adelman and company found that the bugs possessed one of the two mutations in genes coding for their sodium channels that researchers had previously seen in populations of New York bedbugs that were also resistant to this class of insecticide. The mutation is analogous to camouflage—it’s as if the insecticides can’t recognize the nerve endings they typically target. Adelson’s group also saw that the Richmond bugs were producing far higher levels of suspected insecticide-busting proteins in the cytochrome P450 monooxygenase and carboxylesterase families.
With these identifications, Subba Reddy Palli, an entomologist at the University of Kentucky, thinks the study will help in bringing bedbugs to heel. "This paper is good progress toward understanding insecticidal resistance," he says.
Now that his team has identified the genetic sequences bedbugs use to make these detoxifying compounds, Adelman says scientists can check populations worldwide to see how far this defensive capability extends. That will be important for establishing surveillance of growing resistance, as well as for creating new strategies for controlling the critters. For example, he says, if it seems that only the Richmond bedbugs have the genetic mutations needed to crank out this particularly powerful cocktail of enzymes, exterminators should engage in an all-out assault to try to wipe out that bedbug population before it spreads.
The arms race against bedbugs and other insects mirrors the battle with bacterial "superbugs" that have developed antibiotic resistance, such as those that cause staph and tuberculosis. Indeed, bedbugs have a long history of developing defenses against our chemical warfare agents. Bedbug "superbugs" first emerged in the 1950s. DDT (which was banned in 1972 because of human health concerns) wiped out most native bedbug populations in the U.S. by 1950. But some bedbugs survived, developing resistance to it, and later, organophosphate insecticides such as malathion.
Now pyrethroids are losing their effectiveness. "We have all these bedbugs we’ve chased from one chemistry to another," Dini Miller, a co-author of the study, an urban-pest management specialist for the state of Virginia, and a professor at Virginia Tech, says.
Yet the identification of bedbugs’ enzymatic countermeasures could ultimately provide exterminators with fresh ammunition. Besides insecticides, exterminators use a range of methods, including cold air, steam, and vacuums. But these repeated treatments can add up to hundreds or even thousands of dollars. Rejiggering conventional insecticides might still do enough damage to keep bedbugs at bay. "We can look at formulating things in new ways and get better penetration into these bedbugs," Miller says.
Down the road, scientists can base next-generation insecticides on chemicals substantially unlike those that bedbugs have already mastered disarming. Adelman says: "We can come back to the bugs and say, ‘We have a chemical you can no longer deal with given your arsenal. Now try this on for size.’"
New offensive weapons can’t come too soon, as the spread of these brownish or reddish bloodsucking insects has residents of heavy-hit urban areas such as New York City on edge. "Bedbugs don’t kill you," Adelman says, "but they can drive you crazy."
Thank you!!!
Also nothing like a little Chloradane to keep ants out of the house.
There is nothing new about toxins.
I do not know, but I have heard that Fleabaggers at Occupy Portland have an outbreak of scabies.
It turns out that isn't necessarily true.
Birds' eggs started to thin long before DDT.
DDT, Eggshells, and Me Cracking open the facts on birds and banned pesticides
It wasn't banned for "human health concerns" as the article says either.
How about that stuff Ricky the Exterminator uses? I think its made out of Chrysanthemum oil. Kills the heck out of wasps. All natural.
The Richmond bugs had demonstrated strong resistance to a class of insecticides known as pyrethroids—the agents of choice for exterminators.
Does washing the linens in super hot water and soap still kill them?
It’s a good thing that those bed bugs, from millions of years ago, didn’t figure on the vacuum cleaner in their evolutionary development.
The insecticide is not new..
Pyrethroids are just a little bit of tinkering with a natural compound found in a pyrethrin Chrysanthemum.
The compound existed in nature already.
Don’t bring anything that you had into a hotel room into the house until it has had the 140 degree treatment.
Most insecticides are based on naturally occurring toxins. It was just a small trait some had for a long time that probably didn’t matter much, but then the age of insecticides came on and that small trait kept a small number alive, and they bred, and now 60 years later we have bed bugs that are resistant to most insecticides.
Hot washing will kill them.
Unfortunately when daylight comes they scurry between the stitching in the mattress to snooze the day away.
It’s not evolution.. it’s man made selective breeding.
Just like dogs from wolves .
It’s not selective breeding, that involves deliberate action. We chose the most mellow wolves as companions and bred them into dogs. We didn’t chose the bed bugs that were resistant to toxins, we just failed to kill them, that’s evolution.
Well... I can tell you that here in Illinois, since the ban ... we DO have the eagles back.
Correlation does not equal causation. The second article I linked shows that there was very little correlation between DDT use and the thinning of the egg shells of raptors.
Just unintended consequences.
We still selected the survivors.
Also the bed bugs are still bed bugs.. They aren’t on their way to being giraffes.
Different traits among the species isn’t a new species.
Humans come in a variety of hues.. pinks, browns and sallows...They are still humans.. The genetics regulate the outward appearance.
Just a different trait in the same bug.
Actually bedbugs like wood. The most important factor isn't material (fabric vs wood) but distance from places where people spend time hanging out. Bedbugs are lazy and will stay very close to where their food hangs out. They only move away from beds, sofas and chairs when the colony has gotten large enough to push them out further. Dressers in hotel rooms tend to be just a foot or two from the bed.
The safest place would probably be the the closet area on top of one of those folding racks. Up off the carpet and also the furthest distance from the bed.
Does it kill eggs? Hatched bedbugs are not hard to kill if you can get to them, it's the eggs.
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