Susceptibility and fecundity of Bedbugs (Cimex hemipterus) from Yaba College of Technology Lagos exposed to Selected Classes of Insecticides: A short report
Background: Tropical bed bug, Cimex hemipterus, is a nocturnal obligate blood-sucking ectoparasite of humans that is highly prevalent in Nigeria. Bed bug controls heavily rely on the application of several insecticide-based formulations. Insecticide resistance in bed bug populations has been widely reported. In this study, we assessed the mortality of bed bugs following exposure to different classes of insecticides. Methodology: Active adult female bed bugs were collected from students’ halls of residence and exposed to DDT (4%), permethrin (0.75), bendiocarb (0.1) and malathion (4%) insecticide-impregnated papers. Mortality and number of eggs laid by each exposed group were recorded at 90 minutes, 24hrs, 48hrs and 72hrs. Results: The impact of the different assays on bugs mortality revealed DDT to produce a time-dependent outcome with the highest mortality rate [(36.7% (Cl 32.7±38.9)], this was followed by Bendiocarb [31.6% (CI 27.2±35.1)]. In comparison, permethrin and malathion produced the same effect [26.7% (CI 23±30.5)] 24 hours post-exposure. In contrast, malathion and bendiocarb impacted the most mortality [53.3% (49.3±58.7) and 46.6%(42.2±49.5)], followed by permethrin [18.9% (CI 44.6±56.8) after 72 hours. The relative numbers of eggs produced by bedbugs in the DDT, bendiocarb and malathion assays were lower than what was observed in the control and permethrin group 24 hours after exposure. The highest reduction in egg production was observed in the malathion exposed group 48- and 72-hours post-exposure compared to the other insecticides and the control group. Conclusion: This study revealed suspected insecticide resistance to all classes of insecticide used on bed bug populations in Lagos State, Nigeria.