Preimaginal development of Aedes aegypti in brackish water produces adult mosquitoes with thicker cuticles and greater insecticide resistance

Aedes aegypti and Aedes albopictus mosquitoes, the principal vectors of many human arboviral diseases, lay eggs and undergo preimaginal development in fresh water habitats. They have also recently been found to develop in brackish water in coastal areas. Adult females emerging from brackish water-developing Ae. aegypti larvae are shown to possess thicker cuticles and greater resistance to common insecticides used against adults (adulticides) compared with fresh water Ae. aegypti. These findings are compatible with previous findings showing that brackish water Ae. aegypti larvae possess thicker cuticles and greater larvicide resistance. Greater resistance of salinity-tolerant Ae. aegypti to adulticides and larvicides is a hitherto unappreciated problem for controlling arboviral diseases and has implications also for other mosquito-borne diseases.