Genetic Variation of the Southern Corn Rootworm, (Coleoptera: Chrysomelidae)

Corn rootworms of the genus Diabrotica (Coleoptera: Chrysomelidae) are among the most important insect pest of crops in the United States. The southern corn rootworm, Diabrotica undecimpunctata howardi Barber is an economically important pest of corn, cucurbits and peanuts. Genetic analysis of southern corn rootworms, collected from South Dakota, Nebraska, and Arkansas was undertaken using DNA sequences of the nuclear ribosomal first internal transcribed spacer region (ITS1), and a portion of the mitochondrial DNA (mtDNA) cytochrome oxidase I and II genes. Among the 22 beetles subjected to DNA sequencing analysis, no polymorphic nucleotide sites were observed for the ITS1 marker and one variable nucleotide site was observed for the mtDNA marker. The lack of genetic distinction observed in southern corn rootworm populations suggests either high levels of dispersal or a recent geographical expansion from a relatively small base.