Assessment of the genetic structure, variability, and gene flow of the European corn borer Ostrinia nubilalis (Hübner) (Lepidoptera: Crambidae)

Much work has been devoted to the biology and behavior of the European corn borer (ECB), Ostrinia nubilalis (Hübner). This has been driven by the need to determine the impacts of O. nubilalis injury to crops and assess economic damage, develop management tactics, and develop insectice resistance management strategies. Despite having an abundance of literature on the ecology and physiology of the ECB, limited information is available describing genetic variation and population structure. The genetic variability and structure of ECB from 18 sub-populations throughout the upper Midwestern United States was evaluated using amplified fragment length polymorphism (AFLP) as a molecular tool. Genetic variability was higher in regions of lower latitude compared to regions of higher latitude. However, there was no difference in genetic variability at different altitudes. The individuals in the northern regions (ND, SD, MN, and northern NE) were the least genetically diverse compared to the western region (western NE, eastern WY, and northern CO) and the southern region (southeast NE, northern MO, northern KS, and LA). Genetic variability and gene flow was analyzed using POPGENE and AMOVA software. Gene flow values were relatively high across sampled populations with the lowest degree of gene flow in the northern samples and the highest degree of gene flow in the southern samples based on GST values. The differences observed in the respective regions (north vs. south) could be explained by the voltinism pattern differences in those regions. Multiple mating opportunities for the duration of the year would allow a greater mixing of alleles. Based on AMOVA results, a majority of the AFLP variation detected was within each sub-population. Only a small amount of variation was due to variation within the three regions studied. However, the most striking and unexpected result was the low amount of variation among groups supporting a high degree of gene flow