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."
No. The heat coming out of a hair dryer is diffused too quickly to be helpful. You wouldn't be able to penetrate the whole mattress with high enough heat for long enough. The bugs would just feel the heat coming and move.
From what I remember, hot water from a washing machine isn't hot enough to kill them but they may drown. A dryer is better.
It depends upon what you're trying to steam them out of. If they're in a sofa, you're unlikely to get the steam to penetrate the material deep enough at a hot enough temperature for long enough to kill them. That much steam would probably ruin the furniture anyway.
We had bedbugs and we got rid of them ourselves. The reason we could get rid of them without a pest control company was because we had a lot of older/inexpensive furniture we were willing to throw out. If you want to keep your stuff, call a professional.
That’s how evolution works, it’s the unintended consequences of the hunt. Survivors pass on their traits, the dead don’t, hunters always “select” the survivors that way and the survivors evolve.
As for all that other stuff, nobody said nothing about any of that. Time for you to stop obsessing.
GOOD NEWS! Check your online local library. At many of them, including mine, you can borrow Kindle books online. No charge. You have about three weeks to read the book. I've been doing this for the past month.
Not if they're in the mattresses
Um...that IS the very definition of “evolution”.
A random change occurs, it proves beneficial under the circumstances, those with it breed profusely while those that don’t have it die off, leaving one population to replace the other.
Who says?
I, for one, would LOVE bed-giraffes.
No knowledge required. Random chance played out 30 trillion times. You roll 100 dice 30 trillion times, and you, too, will have them all turn up 6's.
Enviromentalists invariably came up with this response to that point: "If we allow you to use it inside your home, any nesting bald eagles there will be jeopardized. No."
You always were a 'deep' thinker...
Sound like evolution in action, more likely.
Only if the bedbug "evolved" into another creature. What is "likely" is that there is a loss, not gain, in genetic information, a failure to produce an enzyme that reacts to the chemicals on the nerve endings - at least that has been the case in other examples of chemical resistant critters.
It would be like if you lost your hearing, you could then stay in an incredibly loud room without getting headaches whereas those who did have hearing would leave. Does this mean that you are "evolving" into a X-man?
Thanks, I’m going to look into it!
Psst! Check your local library online. Many now have a system of allowing the borrowing of books online. Many of these books are fairly new. I just got down reading online a bio of Clarence Darrow which was published just last June.
I contend that maybe it did. The resistant kind.
It would be like if you lost your hearing, you could then stay in an incredibly loud room without getting headaches whereas those who did have hearing would leave. Does this mean that you are "evolving" into a X-man?
Oh, please - that's a completely inappropriate analogy. One particular bug did not become resistant. The new trait developed over thousands of generations (if my guess is correct).
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