Invasion pattern of Aedes aegypti in the native range of Ae. albopictus in Vietnam revealed by biogeographic and population genetic analysis

Since its introduction to Asia, Aedes aegypti has coexisted with the native species Ae. albopictus and has been reported to transmit many infectious diseases. However, the development of efficient disease prevention and vector control is hindered by the relatively poor understanding Ae. aegypti biogeography and genetic diversity in the region. Accordingly, the aims of the present study were to investigate the spatial distribution and relative abundance of Ae. aegypti and Ae. albopictus in different climatic regions (northern temperate and southern tropical) and habitats (domestic, peri-domestic, and natural) and to analyze the genetic diversity and phylogenetic relationships of Ae. aegypti populations in Vietnam using mitochondrial COI gene sequences. Although both Aedes species were observed in most of the study areas, only Ae. albopictus thrived in the northern mountainous areas, and in areas harboring both species, individual abundance of the species was influenced by climate and habitat. For example, the availability of domestic containers facilitated the dominance of Ae. aegypti , whereas temperate climate and natural breeding sites facilitated the dominance of Ae. albopictus . In addition, many genetic polymorphisms were detected in the Ae. aegypti populations, which formed two main genetic groups, and Ae. aegypti abundance seemed to be affected more by interspecific competition and/or climate than genetic diversity. These findings provide insights into the invasion mechanisms and patterns of Ae. aegypti , which depend on the climate and reproductive strategies in the native range of Ae. albopictus in Asia.