Restoration of susceptibility following removal of selection for <scp>Cry34</scp> / <scp>35Ab1</scp> resistance documents fitness costs in resistant population of western corn rootworm, <i>Diabrotica virgifera virgifera</i>

BACKGROUND Management of the corn pest, western rootworm (WCR), Diabrotica virgifera (LeConte) (Coleoptera: Chrysomelidae), relies heavily on planting transgenic expressing toxins produced by bacterium Bacillus thuringiensis (Bt). This has resulted in evolution resistance to all four commercially available Bt targeting coleopteran insects. In this study, we evaluated susceptibility a Cry34/35Ab1-resistant WCR colony seedling and diet toxicity assays after removal from selection for six nine generations. addition, female fecundity, egg fertility, adult lifespan, larval development, emergence were two susceptible colonies assess fitness costs. RESULTS Susceptibility Cry34/35Ab1 was restored removed generations based comparisons relative survival, head capsule width, dry weight plant assays. Thus, pronounced costs associated with documented being within separate studies evaluating specific costs, when reared isoline did not differ between resistant colonies. However, beetles lived longer than which females producing significantly more eggs colonies, no differences fertility. CONCLUSIONS The presence cost that may contribute restoration been other Cry3-resistant populations could have significant impact deployment management practices. Published 2021. article is U.S. Government work public domain USA.