Once nearly wiped out, bed bugs have made an unwelcome return over the last twenty years, spreading across homes and hotels worldwide and leading to various health and comfort issues. While they are not proven to transmit diseases, bed bugs can cause itchy skin, allergic reactions, and psychological stress. A major reason behind their resurgence is their increasing resistance to commonly used insecticides, which makes them much harder to eliminate. Until recently, scientists had limited information about the genetic reasons for this resistance because the full DNA of resistant bed bugs had not been studied.
Dr. Kouhei Toga and Professor Hidemasa Bono from Hiroshima University have made a major contribution in this area. Their research, published in the journal Insects, compares the full genetic information of resistant and non-resistant strains of the common bed bug, Cimex lectularius. Using advanced DNA sequencing tools that allow researchers to read the complete genetic code of an organism, the team carefully mapped the genomes—the full set of DNA instructions—of both types and found specific genetic changes linked to resistance.
One of their most notable discoveries was the extremely high level of resistance in the Hiroshima strain. This strain was thousands of times more resistant to a commonly used insecticide called permethrin compared to the non-resistant strain. Such a dramatic difference points to major changes at the genetic level. Fortunately, the quality of the DNA sequences in both strains was equally high, making it easier for the team to compare them side by side.
Dr. Toga and Professor Bono found hundreds of gene copies, known as transcripts, which are messages copied from DNA that help the body make proteins, and these had changes unique to the resistant bugs. Some of these involved genes already known to be associated with resistance, such as those involved in controlling nerve signals or breaking down harmful chemicals. “These mutations can alter gene function and lead to insecticide resistance,” explained Professor Bono, pointing out how powerful DNA analysis can be in identifying which genes matter most. They also found new mutations in genes not previously connected to resistance—genes that help repair damaged DNA, control how cells divide, and manage how the body uses energy.
To explore what these changes might mean, the team studied how groups of these genes work together in the body. They found that several key body processes may play a role in resistance. These included how cells fix DNA damage, how cells grow and divide, how energy is processed, and how waste is handled inside cells. “DNA damage response, cell cycle regulation, insulin metabolism, and lysosomes were implicated in the development of pyrethroid resistance,” noted Dr. Toga. DNA damage response refers to the body’s way of detecting and repairing damaged genetic material. Cell cycle regulation controls when and how cells grow and multiply. Insulin metabolism helps regulate energy use and storage, and lysosomes are structures in cells that break down waste materials. These findings suggest that insecticide resistance might involve more complex body functions than previously thought.
These discoveries have important real-world impacts. Not only do they help scientists better understand how resistance develops, but they also open up new ways to test for and potentially counteract resistance. Scientists could now use gene editing tools that allow precise changes to DNA to investigate the exact role of these genetic changes, possibly leading to smarter pest control strategies. Broadening the range of genes monitored in pest populations could also make resistance testing more accurate and informative.
In the end, Dr. Toga and Professor Bono’s research marks a key step forward in the fight against bed bugs. By pinpointing the genetic details that help these pests survive insecticide treatments, scientists are now in a better position to outsmart them. As resistant strains continue to spread, this kind of knowledge is essential for building long-term, effective, and science-based approaches to pest control.
Journal Reference
Toga K., Kimoto F., Fujii H., Bono H. “Genome-Wide Search for Gene Mutations Likely Conferring Insecticide Resistance in the Common Bed Bug, Cimex lectularius.” Insects, 2024; 15(737). DOI: https://doi.org/10.3390/insects15100737
About the Authors
Dr. Kouhei Toga is a researcher specializing in genome informatics and molecular biology. He is affiliated with Hiroshima University, where his work focuses on the genetic mechanisms underlying insecticide resistance and genome evolution. With expertise in advanced DNA sequencing and bioinformatics, Dr. Toga aims to better understand how small genetic changes can lead to major shifts in an organism’s behavior and survival strategies.
Professor Hidemasa Bono is a leading figure in genome informatics and bio-data analysis at Hiroshima University. He heads initiatives at the Genome Editing Innovation Center, concentrating on decoding complex biological data to drive innovations in health and agricultural sciences. Professor Bono’s work bridges cutting-edge technology with real-world applications, using powerful computational tools to uncover the hidden roles of genes in resilience, disease, and adaptation. Together, Dr. Toga and Professor Bono are helping shape the future of pest management and genetic research.
