Ingestion-mediated toxicity of dinotefuran against Aedes aegypti and its implications for future sugar based toxic bait development

Aedes aegypti (Linnaeus, 1762) is an important vector of dengue, chikungunya, Zika, and yellow fever viruses. The increasing spread of insecticide resistance in Aedes populations highlights the need for alternative control strategies and insecticides with novel modes of action. Dinotefuran, a third-generation neonicotinoid, has shown promising activity against several vector species, but information on its oral toxicity in Aedes aegypti remains limited. The oral toxicity of dinotefuran was evaluated using a sugar-feeding bioassay under laboratory conditions. Female Aedes aegypti mosquitoes (2–5 days old) were exposed to 10% sucrose solutions containing dinotefuran at 0.00001, 0.0001, 0.0005, and 0.001 mg/mL. Uranine (0.8%) was used as a fluorescent feeding marker, and mortality was assessed after 24 h among fluorescent-positive mosquitoes. The mean sugar meal volume was quantified fluorometrically. Mortality data were analyzed using a generalized linear model with a binomial error distribution and probit link, using log10-transformed dinotefuran concentration as the predictor. Because overdispersion was detected, inference was based on a quasibinomial model with a probit link. Dinotefuran produced a clear concentration-dependent increase in mortality, reaching 81.86% at 0.001 mg/mL, while feeding rates ranged from 70% to 100%. The mean meal volume was 0.1 µL per mosquito and mean body weight was 1.427 mg. The estimated LC₅₀ and LC₉₅ were 0.00029 mg/mL (95% CI: 0.00022–0.00037) and 0.00405 mg/mL (95% CI: 0.00236–0.00696), respectively. The corresponding amounts were 0.027 ng/mosquito and 0.391 ng/mosquito, yielding LD₅₀ and LD₉₅ values of 0.019 ng/mg and 0.274 ng/mg, respectively. These findings provide laboratory-based evidence of oral toxicity of dinotefuran against adult Aedes aegypti and support further investigation of dinotefuran containing sugar-based toxic bait formulations under future experimental conditions.