Invasion Pattern of Aedes aegypti in the Native Range of Ae. albopictus in Vietnam Revealed by Biogeographic and Population Genetic Analysis

SIMPLE SUMMARY: Over the last few decades, the yellow fever mosquito Aedes aegypti has become one of the most abundant and dangerous arbovirus vectors in Asia. In this study, we assessed the invasion pattern of Aedes aegypti by investigating its distribution, relative abundance with its closest competitor Aedes albopictus, and genetic diversity in Vietnam. Our results revealed that the distribution and abundance of this species are significantly influenced by climate region, larval habitat, and the presence of Aedes albopictus. Furthermore, we found a high level of genetic diversity in Aedes aegypti, with two major genetic lineages. The results of this study have significant potential for optimizing vector control strategies regarding future mosquito invasion and outbreak prediction in Asia. ABSTRACT: Since its introduction to Asia, Aedes aegypti has coexisted with the native species Ae. albopictus and has been reported to transmit several infectious diseases. However, the development of efficient disease prevention and vector control is hindered by the relatively poor understanding of the biogeography and the genetic diversity of Ae. aegypti in the region. This study aimed to determine the invasion patterns of Ae. aegypti by evaluating the distribution and abundance of Ae. aegypti and Ae. albopictus in different climatic regions (northern temperate and southern tropical regions) and habitats (domestic, peri-domestic, and natural). We further analyzed the genetic diversity and phylogenetic relationships of Ae. aegypti populations in Vietnam using mitochondrial COI gene sequences. Both Aedes species were observed at most of the study sites, but only Ae. albopictus thrived in northern mountainous areas. In sympatric ranges, the individual abundance of the species was influenced by regional climate and habitats. The tropical climate and availability of domestic containers facilitated the dominance of Ae. aegypti, whereas temperate climates and natural breeding sites facilitated that of Ae. albopictus. In addition, many genetic polymorphisms were detected in the Ae. aegypti populations, which formed two distinct genetic groups; however, this genetic diversity is unlikely to be relevant to the invasive success of Ae. aegypti. These findings provide insights into the mechanisms and patterns of Ae. Aegypti invasion, which depend on the climate and reproductive strategies in the native range of Ae. albopictus in Asia.