[Population genetic structure of Bemisia tabaci (Hemiptera: Aleyrodidae) utilizing microsatellite markers]

We aimed to characterize the population genetic structure within and among five Bemisia tabaci (Gennadius) populations collected from different host plants and geographic regions by using microssatelites as a molecular marker. Each population was represented by 19 specimens. The host plants and geographic origins of these populations were described as follows: Pop 1: Squash Barreiras (BA); Pop 2: Cotton Barreiras (BA); Pop 3: Soybean Campinas (SP); Pop 4: Tomato Cruz das Almas (BA); and Pop 5: Soybean Rondonópolis (MT). Six polymorphic loci were observed, which discriminated 31 different alleles in the studied populations, with a mean number of alleles per population of 3.30 (2.67 - 4.00). Using Fisher's Exact test, it was observed that at least three populations were in Hardy-Weinberg equilibrium for most of the studied loci (six). The dendrogram (UPGMA) separated populations into groups mainly related to the geographic origin of the samples. Only population 5 differed from the others at a 0.15 distance (74.5% group consistency). The most similar populations were 1 and 2, with a 0.01 distance (65.3%). This is in agreement with their geographic origins and it was not consistent with host specificity. The results suggest considerable gene flow (7.3%) among all whitefly populations and indicate that a better understanding of the gene flow in populations of B. tabaci associated with different hosts is required for the management of this insect.