Field-evolved resistance in European corn borer (Ostrinia nubilalis) to all four available insecticidal proteins in Bt corn has been detected in four provinces of Canada since 2018. Evolution and spread of resistance are functions of gene flow, and therefore dispersal, so design of effective resistance management and mitigation plans must take insect movement into account. Recent advances in characterizing European corn borer movement ecology have revealed a number of surprises, chief among them that a large percentage of adults (~90%) disperse from the natal field via true migratory flight behavior, most before mating. This conclusion is supported by multiple lines of triangulated evidence from multiple laboratories in North America, Europe, and Asia. This understanding undermines a number of common key assumptions about adult behavior, patterns of movement, and gene flow, and stresses the need to reassess how ecological data are interpreted and how European corn borer movement in models should be parameterized. Effective Bt resistance prevention and mitigation strategies for this species must account for high gene flow consistent with improved understandings of this species’ complex movement ecology, including migratory behavior.
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