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Updated: Oct 15, 2025
A Method for Evaluating Insecticide Efficacy against Bed Bug, Cimex lectularius, Eggs and First Instars
Published on: March 15, 2017
Multiple Mechanisms Conferring Broad-Spectrum Insecticide Resistance in the Tropical Bed Bug (Hemiptera: Cimicidae)
Kai Dang1,2, Stephen L Doggett2, Xin-Yeng Leong1,3
1Urban Entomology Laboratory, Vector Control Research Unit, School of Biological Sciences, Universiti Sains Malaysia, Penang, Malaysia.
Abstract:
The modern resurgence of the common (Cimex lectularius L.) and tropical bed bugs (C. hemipterus [F.]) is thought to be primarily due to insecticide resistance. While there are many reports on insecticide resistance mechanisms in C. lectularius, such information in C. hemipterus is limited. We examined dichloro-diphenyl-trichloroethane (DDT), malathion, deltamethrin, permethrin, lambda-cyhalothrin resistance, and the underlying mechanisms in several C. hemipterus strains (Australia: Queensland [QLD-AU]; Malaysia: Kuala Lumpur [KL-MY], Tanjung Tokong [TT-MY], Christian [CH-MY], and Green Lane [GL-MY]). We used a surface contact method, synergism studies (utilizing piperonyl butoxide [PBO], S,S,S-tributyl phosphorotrithioate [DEF], and diethyl maleate [DEM]), and molecular detection of kdr mutations. Results demonstrated that all C. hemipterus strains possessed high resistance to DDT and the pyrethroids and moderate to high resistance to malathion. Synergism studies showed that deltamethrin resistance in all strains was significantly (P < 0.05) inhibited by PBO. In contrast, deltamethrin resistance was not affected in DEF or DEM. Similar findings were found with lambda-cyhalothrin resistance. Malathion resistance was significantly (P < 0.05) reduced by DEF in all strains. Resistance to DDT was not affected by DEM in all strains. Multiple kdr mutations (M918I, D953G, and L1014F) were detected by molecular analyses. TT-MY strain was found with individuals possessing three kdr mutation combinations; D953G + L1014F (homozygous susceptible: M918), M918I + D953G + L1014F (heterozygous resistant: I918), and M918I + D953G + L1014F (homozygous resistant: I918). Individuals with M918I + D953G + L1014F (homozygous resistant: I918) survived longer on deltamethrin (>12 h) than those (≤1 h) with other combinations. M918I + L1014F mutations most likely conferred super-kdr characteristic toward pyrethroids and DDT in C. hemipterus.
Insights
Tropical bed bugs (Cimex hemipterus) show high resistance to common insecticides like DDT and pyrethroids. Resistance is linked to specific kdr gene mutations, with some combinations conferring
Area of Science:
- Entomology
- Molecular Biology
- Pest Management
Background:
- The resurgence of bed bugs, particularly Cimex hemipterus, is a growing global concern.
- Insecticide resistance is a primary driver of bed bug resurgence, yet mechanisms in C. hemipterus are less understood than in Cimex lectularius.
- Understanding resistance mechanisms is crucial for developing effective control strategies.
Purpose of the Study:
- To investigate insecticide resistance profiles in tropical bed bug (Cimex hemipterus) strains.
- To elucidate the underlying mechanisms of resistance, including metabolic and target-site resistance.
- To identify specific genetic mutations (kdr mutations) associated with insecticide resistance in C. hemipterus.
Main Methods:
- Assessed resistance to dichloro-diphenyl-trichloroethane (DDT), malathion, deltamethrin, and lambda-cyhalothrin using surface contact bioassays.
- Conducted synergism studies with piperonyl butoxide (PBO), S,S,S-tributyl phosphorotrithioate (DEF), and diethyl maleate (DEM) to explore metabolic contributions.
- Employed molecular techniques to detect and analyze kdr mutations (M918I, D953G, L1014F) in C. hemipterus populations.
Main Results:
- All examined C. hemipterus strains exhibited high resistance to DDT and pyrethroids, and moderate to high resistance to malathion.
- Synergism studies indicated that PBO significantly inhibited deltamethrin and lambda-cyhalothrin resistance, suggesting the involvement of cytochrome P450 enzymes.
- DEF significantly reduced malathion resistance, implicating esterases, while DDT resistance was unaffected by DEM. Multiple kdr mutations were identified, with specific combinations (e.g., M918I + L1014F) strongly correlating with enhanced survival against pyrethroids and DDT.
Conclusions:
- Cimex hemipterus populations display widespread resistance to major insecticide classes.
- Resistance mechanisms involve both target-site mutations (kdr) and potentially metabolic detoxification pathways.
- The identified kdr mutations, particularly M918I and L1014F, are critical genetic factors conferring high-level resistance, essential knowledge for integrated pest management programs.
