Population structure of the peridomestic mosquito Ochlerotatus notoscriptus in Australia

Abstract

Ochlerotatus notoscriptus (Skuse) (Diptera: Culicidae) is the predominant peridomestic mosquito in Australia where it is the primary vector of dog heartworm, Dirofilaria immitis (Leidy), and a potentially important vector of arboviruses (Barmah Forest, Ross River) with geographical variation of vector competence. Although widespread, Oc. notoscriptus has low dispersal ability, so it may have isolated subpopulations. The identification of gene flow barriers may assist in understanding arbovirus epidemiology and disease risk, and for developing control strategies for this species. We investigated the population structure of Oc. notoscriptus from 17 sites around Australia, using up to 31 putative allozyme loci, 11 of which were polymorphic. We investigated the effect of larval environment and adult morphology on genetic variation. At least five subpopulations were found, four in New South Wales (NSW) and one unique to Darwin. Perth samples appear to be a product of recent colonization from the Australian east coast. For NSW sites, a Mantel test revealed an isolation by distance effect and spatial autocorrelation analysis revealed an area of effective gene flow of 67 km, which is high given the limited dispersal ability of this species. No consistent difference was observed between 'urban' and 'sylvan' habitats, which suggests frequent movement between these sites. However, a finer-scaled habitat study at Darwin revealed small but significant allele frequency differences, including for Gpi. No fixed allozyme differences were detected for sex, size, integument colour or the colour of species-diagnostic pale scales on the scutum. The domestic habit of Oc. notoscriptus and assisted dispersal have helped to homogenize this species geographically but population structure is still detectable on several levels associated with geographical variation of vector competence.

Analysis of the genetic variability and structure of Ochlerotatus taeniorhynchus (Diptera: Culicidae) populations from the Colombian Atlantic coast on the basis of random amplified polymorphic DNA markers

“…It also suggested that the genetic homogeneity was probably caused by a continuous and random gene flow, with a restrictive random gene drift, along a major part of the Colombian Atlantic coast. In contrast, other studies, such as that of Foley et al (2004), showed a clear significant spatial structure in mosquito species. They found a strong spatial structure in the peridomestic mosquito O. notoscriptus, with correlograms of different loci showing positive and significant values in the first distance classes and significant and negative values at the largest distances, reflecting isolation by distance.…”

Anthropogenic Environmental Change, Mosquito-borne Diseases and Human Health in New Zealand

“…Aedes notoscriptus is the dominant species, most likely as a result of its extensive utilization of container habitats. This species is the predominant peridomestic mosquito in Australia (Foley et al, 2004), and the same pattern is being observed in northern New Zealand. Culex quinquefasciatus is the other exotic mosquito commonly found, but it appears to have a more restricted distribution (Derraik and Slaney, 2005).…”

Association Between Habitat Size, Brushtail Possum Density, and the Mosquito Fauna of Native Forests in the Auckland Region, New Zealand

“…In Australia, Ae. notoscriptus is the main peridomestic mosquito species (Foley et al, 2004), and this pattern is now seen in urban and suburban areas in the Auckland region (e.g., Derraik, 2005a). A similar pattern of invasion would likely apply to Ae.…”