Detailed bedbug genome analysis may improve pesticides

Bedbugs. Just mentioning the tiny, biting insects that live on human blood and infest mattresses, couches, and bedding strikes fear into most people. In addition to the anxiety, itching, and rashes an outbreak can cause, bedbugs can be difficult to identify and expensive to treat.

Thanks to a new University of Texas at Arlington study published in the Journal of Heredity, scientists now have a better genetic understanding of the insect. The research offers an updated genome analysis of the common bedbug Cimex lectularius, providing new insight for those working to prevent bedbug infestation, develop remediation strategies and track pesticide resistance.

“This new high-quality reference genome provides a valuable resource for enhancing scientific investigations into this medically and economically resurging pest,” said author Todd Castoe, professor of biology at UTA.

“We now have an important additional tool for studying patterns of human-associated evolution and adaption for this insect that has wreaked havoc on human populations since the beginning of civilization,” added co-author Yannick Francioli, a Ph.D. student in Dr. Castoe’s lab.

Although bedbugs have been mentioned in the written record for more than 3,000 years, the pest rose to prominence in the 1940s, when infestations plagued military bases during World War II. With the introduction of the powerful pesticide DDT (dichlorodiphenyltrichloroethane), the insect was thought to be eradicated in many industrialized nations.

In the 1990s, a combination of the elimination of DDT use due to health concerns, increased pesticide resistance among insects, and increased international travel helped fuel a resurgence of bedbug infestations. Bedbug outbreaks around the world now routinely make news headlines, such as the infestation in Paris hotels before the summer 2024 Olympic Games.

To better understand the genetics of the bedbug, Castoe and Francioli, along with researchers from Virginia Polytechnic Institute and State University, the University of Arkansas, the Dana-Farber Cancer Center, Harvard Medical School, and the Broad Institute of Massachusetts Institute of Technology and Harvard University, obtained a sample specimen of the insect and flash froze it to allow its DNA to be extracted.

From that extraction, the team was able to create a chromosome-level reference genome for the insect using PacBio long-read and Omni-C proximity genetic sequencing tools. This approach, combined with sampling additional male and female individuals, allowed the team to map a contiguous bedbug genome with 15 chromosomes (13 autosomes and two sex chromosomes: X1 and X2), providing a comprehensive genetic map that enhances our understanding of the pest’s biology, evolution and insecticide resistance.

Specifically, the identification of sex chromosomes will help researchers understand the genetic basis of sex determination in bedbugs. This can be particularly useful for developing targeted pest control strategies that exploit sex-specific traits.

“The creation of a chromosome-level reference genome gives us a new and highly accurate contiguous map of the bedbug’s genetic material,” said Castoe. “This new foundational resource will allow researchers to further understand the genetic basis of traits of the insect that cause issues such as insecticide resistance, which is crucial for developing more effective pest control strategies.”