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. FST 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 (IN 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.