Title: Genetics of United States Populations of Western Corn Rootworm ( Diabrotica virgifera virgifera) and Implications for Bacillus thuringiensis (Bt) Corn Management Authors
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: February 15, 2009
Publication Date: April 7, 2009
Citation: Oswald, K., Bagley, M., Stoltz, E., French, B.W., Nielson, C.N. 2009. Genetics of United States Populations of Western Corn Rootworm (Diabrotica virgifera virgifera) and Implications for Bacillus thuringiensis (Bt) Corn Management. IWGO Meeting, Munich, Germany, April 5-8, 2009. Technical Abstract: Western corn rootworm (Diabrotica virgifera virgifera; WCR) were sampled from across much of their US range for population genetic analyses. We assayed allelic variation at microsatellite loci, including markers within a cadherin-like gene, a locus shown to be correlated with resistance to Bacillus thuringiensis (Bt) in other insects, and sequence polymorphism within the mitochondrial cytochrome oxidase subunit I (COI) locus. Patterns of variation among genomes produced largely concordant results as Midwest and Eastern US populations were, for the most part, undifferentiated, suggesting high levels of gene flow. Southwest US populations displayed moderate to high levels of differentiation, with some discordance among data sets concerning the level of differentiation of the New Mexico population. For Midwestern and Eastern US populations, evidence for a population bottleneck, followed by a recent population expansion was found. However, given the species’ remarkable ability to evolve resistance to almost all control strategies that have been implemented, this demographic history does not appear to have strongly diminished its capacity for adaptation. Implications for management strategies designed to maximally delay adaptation to corn containing the Bacillus thuringiensis, (Bt) transgene will be discussed.