Lethal and sublethal effects of toxic sugar baits differ among insecticide resistant and insecticide susceptible populations of Aedes aegypti.

Widespread insecticide resistance and the potential for sublethal exposures to alter mosquito fitness have increased interest in alternative approaches such as attractive toxic sugar baits (ATSBs), yet their lethal and sublethal effects in insecticide-resistant versus susceptible populations remain poorly understood. We evaluated the lethal and sublethal effects (LC25) of a novel boric acid and dinotefuran ATSB on ingestion, mortality, blood feeding, and reproductive traits in permethrin-resistant and permethrin-susceptible Aedes aegypti. Aedes aegypti is the primary global vector of dengue, Zika, chikungunya, and yellow fever viruses, placing billions at risk and underscoring the need for sustainable vector control strategies. ATSB affected ingestion, mortality, and reproductive traits in a resistance-dependent manner. Susceptible mosquitoes exhibited reduced ATSB ingestion, whereas resistant mosquitoes showed increased ingestion, suggesting that resistance status modifies feeding responses to the bait formulation. ATSB ingestion increased acute mortality in both strains, with a stronger effect in susceptible mosquitoes, and similarly shortened survival time across strains, indicating consistent sublethal toxicity regardless of resistance status. ATSB reduced blood feeding in both strains, suggesting potential downstream effects on pathogen transmission. Fertility exhibited a significant resistance × treatment interaction, with ATSB increasing fertility in resistant mosquitoes but reducing it in the susceptible strain. These findings indicate that the effects of this ATSB on mosquito fitness and arbovirus transmission-related traits are strongly influenced by permethrin resistance, highlighting the importance of incorporating resistance status into ATSB evaluations and integrated vector control strategies.