Investigating Olfactory Preferences in Aedes aegypti aegypti and Aedes aegypti formosus through Olfactometer Trials: A Display of Different Preferences for Individual Human Odors across Mosquito Subspecies

Abstract

Female mosquitoes that feed on human hosts transmit a variety of viral diseases and have become a major global health concern. In particular, Aedes aegypti is the primary vector of dengue, yellow fever, chikungunya, and Zika, which are debilitating diseases that create a substantial health burden globally. While many have studied odor preferences in domestic Aedes aegypti aegypti because this subspecies specifically feed on human hosts, we know less about preferences in forest Aedes aegypti formosus that primarily feeds on animal hosts but can still transmit diseases. In this study, we observed preferences of these mosquitoes for individual humans and a guinea pig host through olfactometer trials. We also collected odor samples to analyze the compounds and their relative abundances present in each subject’s odor profile. We found that domestic mosquitoes prefer all humans over the animal host. While forest mosquitoes did favor the animal host over all human subjects, the strain did preferentially choose certain human individuals over others. Odor extraction data showed that similar odor compounds appeared across human subjects but in different relative quantities. The data suggested that geranylacetone may act as a repellant of Aedes aegypti mosquitoes because the subjects that were more attractive to domestic females had the least amounts of this compound. Overall, these findings demonstrate variation in preference across subspecies. This is important in understanding the evolution of olfactory responses in the two subspecies. Additionally, this information will improve control efforts against arboviruses transmitted by Aedes aegypti, as different measures may be taken to control the two different strains.