Characterization of Volatile Organic Compounds from Waterborne and Nectar-Dwelling Yeasts Attractive to Asian Tiger Mosquitoes

Volatile organic compounds (VOCs) emitted by floral scents and waterborne microorganisms can influence mosquito behavior. However, the role of nectar-dwelling yeasts and their VOCs in mosquito nectar seeking behavior, compared to waterborne microorganisms influencing oviposition, remains underexplored. To investigate this in Aedes albopictus , a species well adapted to urban environments, we characterized yeast communities from visited and non-visited flowers, as well as from colonized and non-colonized breeding-site waters in urban community gardens. We identified yeast species and their associated VOCs involved in mosquito behavioral responses. Yeast communities differed between floral and aquatic habitats, although several taxa, including generalist species frequently isolated from nectar, were shared between both environments, likely through insect transmission or pollen dissemination. Two nectar-dwelling yeasts, Metschnikowia reukaufii and Aureobasidium pullulans , attracted males and females through the emission of 3-methyl-1-butanol, ethanol, 2-methyl-1-butanol, and isobutyl alcohol, respectively. In contrast, two waterborne yeasts, Cystobasidium slooffiae and Rhodotorula mucilaginosa , which were preferentially associated with colonized breeding sites, attracted gravid females and produced blends characterized by lower VOC richness and reduced concentrations of 3-methyl-1-butanol and 2-methyl-1-butanol. These results highlight the importance of yeast-emitted VOCs as semiochemicals guiding nectar feeding and oviposition in mosquitoes and call for further investigation into their ecological relevance.