Modeling a western corn rootworm, Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae), maturation delay and resistance evolution in Bt corn

Abstract

Background: Emergence delay and female-skewed sex ratios among adults of Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae) from Bt corn have been reported in field studies. The authors used a simulation model to study the effect of a maturation delay and a female-skewed sex ratio for D. v. virgifera emerging from Bt corn on the evolution of Bt resistance.

Results: The effect of skewed toxin mortality in one sex on evolution of Bt resistance was insignificant. An emergence delay among resistant beetles from Bt corn slowed resistance evolution. A shift in the time of emergence for homozygous susceptible beetles from Bt corn did not have a significant effect on the evolution of Bt resistance in D. v. virgifera.

Conclusion: This simulation study suggested that skewed toxin mortality in one sex and an emergence delay for beetles in Bt corn are not major concerns for managing resistance by D. v. virgifera to single-toxin or pyramided Bt corn.

Keywords: Bt corn; Diabrotica virgifera virgifera; resistance management.