As the war on bedbugs wears on, scientists try to understand the invasive pests so they can kill the suckers.
Now, Ohio State University researchers have conducted the first genetic study to identify pesticide-resistant genes the bugs carry. It may lead to new ways of controlling the bugs in the future.
"Right now, these studies are still preliminary and only scratching the surface of the bedbug genome," said Omprakash Mittapalli, Ph.D., assistant professor of entomology at Ohio Agricultural and Development Center and corresponding author of the study. "But bedbugs could be a lot more complicated than previously thought."
Mittapalli and his team analyzed laboratory-reared bedbugs vulnerable to insecticides, and compared them to pesticide-exposed bedbugs found in a local apartment in 2009 and 2010. Researchers identified more than 35,000 expressed sequence tags, tiny portions of a gene that can be used to help identify unknown genes and map their positions within the genome.
"The genetic bases for these genes could enable us to formulate newer development strategies that may be more effective than what we have right now," said Mittapalli. "But a lot more studies need to be done, not only to identify candidate genes, but also to get a better understanding of the biology of the insect."
The study, published in the journal PLoS ONE, found that there were differences in a gene, known as CYP9, between the bedbugs exposed to pesticides and the non-exposed bedbugs.
In other words, scientists say bedbugs may be genetically resistant to the pesticides currently used to get rid of them.
"If we can suppress the expression of that gene and see if bedbugs are still able to overcome the pesticide, then we'll be able to see that that gene is involved in overcoming pesticide resistance," said Mittapalli.
Jim Fredericks, director of technical services at the National Pest Management Association, said that the preliminary genetic findings are an important step in the total bedbug extermination process.
"Bedbug research came to a standstill about 40 years ago when people thought that bedbugs were gone, so the basic biology in terms of today's standards has never been investigated," said Fredericks. "By looking at the genomics of the bug, we start to get a better picture of how these things work, especially in terms of pesticide resistance."
And in a press release, Mittapalli said that pinpointing such defense mechanisms and the associated genes could lead to the development of novel methods of control that are more effective.
Bedbugs are flightless, nocturnal parasitic insects that were first noticed in the United States in the early 1700s. They afflicted Americans until World War II, when the extensive use of DDT wiped out most of the pests.
But when DDT was banned, the bedbugs came marching back in. Over the past decade, almost every continent has recorded bedbug infestation, with an estimated 100 to 500 percent annual increase. The bedbug plague has forced people to spend billions of dollars on treatments. And the pests have been known to resurface in homes and buildings weeks or months after extermination.
Scientists say the banning of DDT is just part of the reason. They also cite greater foreign travel, more frequent exchange of second-hand furniture and clothing and the bugs' increasing resistance to pesticides.