Evidence of cryptic genetic lineages within Aedes notoscriptus (Skuse)

Aedes notoscriptus (Skuse), a mosquito from the southwest Pacific region including Australia, has been implicated as a vector of arboviruses, but its status as a species is unclear. To investigate the taxonomic situation, we assessed genetic variation and phylogenetic relationships among Ae. notoscriptus from the east coast of Australia, Western Australia and New Zealand. Phylogenetic analyses of DNA sequence data from mitochondrial markers indicate that Ae. notoscriptus is a complex of divergent genetic lineages, some of which appear geographically restricted, while others are widespread in eastern Australia. Samples from New Zealand and Western Australia were related to populations from one southern Australian lineage. Nuclear markers show no evidence of genetic isolation by geographic distance in the overall sample of mosquitoes, but strong isolation by distance is obvious within two of the lineages, supporting their status as isolated gene pools. The morphological character of wing centroid size variation is also associated with genetic lineage. These findings point to the possibility that Ae. notoscriptus is a complex of species, highlighting the need to understand physiological and ecological differences that may influence future control strategies.