Invasive brown algae (Sargassum spp.) as a potential source of biocontrol against Aedes aegypti

Influxes of sargassos are responsible for economic and environmental disasters in areas where they bloom, especially in regions whose main income relies on tourism and with limited capacity for sanitation and public health response. A promising way of valorization would be to convert this incredible biomass into tools to fight the deadly vector mosquito Aedes aegypti. In the present study, we generated hydrolates and aqueous extracts from three main Sargassum morphotypes identified in Guadeloupe (French West Indies): Sargassum natans VIII, Sargassum natans I and Sargassum fluitans. We conducted a chemical characterization and a holistic evaluation of their potential to induce toxic and behavioral effects in Ae. aegypti. Despite the low insecticidal potential observed for all the extracts, we found that S. natans VIII and S. fluitans hydrolates deterred oviposition, induced contact irritancy and stimulated blood feeding behavior in host seeking Ae. aegypti females, while aqueous extracts from S. natans I and S. fluitans deterred both blood feeding behavior and oviposition. Chemical characterization evidenced the presence of phenylpropanoid, polyphenols, amino acids and esters. Thus, Sargassum spp. aqueous extracts and hydrolates could be used to manipulate Ae. aegypti behavior and be valorized as control tools against this mosquito.