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."
That’s a very simple truth, but it will never stop people from telling you that insects are “evolving” resistance to insecticides or bacteria are “evolving” resistance to antibiotics. The mutation that confers resistance to such things also results in a weaker organism under normal circumstances. Only when they are given an unusual advantage (such as the introduction of pesticides and antibiotics) are they able to reproduce.
I feel your pain... get some of that foam to try to plug up any holes...
It’s Sunday morning. Why so grumpy?
You are either going to have to get a high temperature thermostat that lets you set it at 120 or you are going to just have to bypass it and risk burning your house down.
You are also going to have to make sure there are no bugs or eggs in any of the stuff you take to the motel.
You are also going to have to make sure there are no bugs or eggs in any of the stuff you bring back from the (likely) infested motel.
The Obama Index Factor. Fast and Furious Bed Bugs.
Nooooo! I hadn't even thought of that and I borrow books every week! I'm so obsessed about getting those buggers I won't travel to hotels anymore. When my daughter comes home from school she has to leave her stuff outside until I look at it.... I know I have a mental problem about this.
Not sure I follow you but that is textbook evolution. Also, mutations don’t always result in a weaker organism that can’t reproduce other than under those circumstances. Mutations are simply changes, some are weaker, some aren’t.
Libraries are a big issue.
http://bedbugger.com/2009/09/23/denver-public-library-book-return-infested-with-bed-bugs
My parents told me they rented a furnished house back in the 30’s when they were first married. It had bed bugs so they took the mattress and springs outside and set fire to them. My dad always was a kind of a practical take-charge kind of guy!
You’re right.
It looks like there are a number of web sites for reporting them.
I’m right. Not left.
Thanks for the advice.
The little buggers are too small for me to blast with my 9mm!
Bfl
Thanks for posting that.
Think about it... children’s books are borrowed quite frequently and usually left in a child’s bedroom. So, a few of those buggers getting into the pages is more common than not. Don’t think you have a mental problem at all... if you do then I’m right with you. I constantly check my children’s heads for lice... especially in the Fall and in the Spring. Right now... I am itchy just reading this post. LOL!!
Bookmark for later reference.
Your Dad was definitely a smart guy... he figured out “heat” killed them in the 30’s!! What is weird to me is for so many years, I thought they were just something of “ancient” times. “Night, night, don’t let the bedbugs bite” was just a silly, children’s poem. Not anymore!
A little DDT will beat them back.
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