Cryptic Diversity and Demographic Expansion of Malaria Vectors in Malaysia.

Although Malaysia is considered free of human malaria, there has been a growing number of cases. This alarming trend highlighted the need for our understanding of this parasite and its associated vectors, especially considering the role of genetic diversity in the adaptation and evolution among vectors in endemic areas, which is currently a significant knowledge gap in their fundamental biology. Thus, this study aimed to investigate the genetic diversity of , , , and -the vectors for malaria in Malaysia. Based on cytochrome c oxidase 1 () and internal transcribed spacer 2 () markers, the genealogic networks of showed a separation of the haplotypes between Peninsular Malaysia and Malaysia Borneo, forming two distinct clusters. Additionally, the genetic distances between these clusters were high (2.3-5.2% for ) and (2.3-4.7% for ), indicating the likely presence of two distinct species or cryptic species within . In contrast, no distinct clusters were observed in , , or , implying a lack of pronounced genetic differentiation among their populations. It is worth noting that there were varying levels of polymorphism observed across the different subpopulations, highlighting some levels of genetic variation within these mosquito species. Nevertheless, further analyses revealed that all four species have undergone demographic expansion, suggesting population growth and potential range expansion for these vectors in this region.