Population structure and dispersal of the saltmarsh mosquito Aedes vigilaxin Queensland, Australia

Population genetics of the mosquito Aedes vigilax (Skuse) (Diptera: Culicid ae), a major vector of arboviruses (e.g. Barmah Forest, Ross River), were i nvestigated to obtain an indirect estimate of mosquito dispersal characteri stics in typical habitats of Aedes vigilax in south-east Queensland: on the off-shore islands of Moreton Bay and on the mainland where disjunct breedi ng populations of Ae. vigilax are distributed along intertidal marsh. Six a llozyme loci were assessed for genetic differentiation between samples from 11 localities. Significant larval variation between some breeding sites wa s attributed to site-specific selection. Non-significant genetic differenti ation was found among collections of adult mosquitoes caught in light traps throughout the study area (exceeding 60 x 27 km), indicating widespread di spersal. As distances of less than or equal to 9km over water did not appea r to act as effective barriers to Ae. vigilax dispersal, localized control activities applied to Ae. vigilax breeding sites are unlikely to be effecti ve against the vagile adult population. Therefore, the contiguous shires pr ogramme of broad acre control is endorsed to prevent the spread of arboviru ses carried by Ae. vigilax.