Genomic signatures of adaptation to Bt-expressing transgenic crops in the agricultural pest, Helicoverpa zea

Insect adaptation to management approaches in agricultural landscapes is common and results in economic losses. Detection of emerging adaptive changes that result in pest resistance to management tools, prior to significant crop damage, would benefit the agricultural community. It had been hypothesized that new genomic approaches could track molecular signals of emerging resistance and trigger efforts to pre-empt widespread damage. We tested this hypothesis by quantifying genomic changes in the pest, Helicoverpa zea, over a 15 year period concurrent with commercialization and subsequent loss of efficacy of transgenic Bt-expressing crops. Our results demonstrate the complex nature of evolution in agricultural ecosystems and provide insight into the potential for and pitfalls associated with use of genomic approaches for resistance monitoring.