Gene flow in Aedes albifasciatus (Diptera: Culicidae) from central Argentina

To estimate gene flow among populations of the floodwater mosquito Aedes albifasciatus, allozymic frequencies were analyzed at 16 loci in samples from 6 localities in central Argentina. Expected mean heterozygosity ranged from 0.057 to 0.137. F-ST was significant For 5 of 11 polymorphic loci; mean value was 0.024, which gave an Nm of 50.96. Levels of genetic identity among samples were high (I-N between 0.9815 and 0.9988) even between populations 500 km apart. However, there was a significant correlation between genetic and geographic distance, which indicated that although the 6 populations were at approximate equilibrium because of gene flow, this was restricted by distance. The distribution of allele frequencies possibly reflected the present status of a single large population occupying this region in the past. When geological change separated breeding areas, a moderate level of gene flow may have resulted in the current genetic structure of the populations.