Effect of Bt Maize on Adult Head Capsule Width of Western Corn Rootworm Beetles

The success of the current resistance management plan for genetically engineered (GE) maize that targets the rootworm complex depends on the high rates of mating between resistant and susceptible beetles. However, this could lead to assortative mating, which can further result to an alteration in the rate of resistance evolution. Alexzandra F. Murphy of Purdue University and colleagues examined the adult head capsule widths of western corn rootworm beetles in different refuge configurations. Beetles were grouped into treatments based on the hybrid and location of the natal host plant.

Results showed that the average head capsule width of males coming from Bt maize targeting larval rootworms (Bt-RW maize) are significantly smaller than the average head capsule width of males from non-Bt refuge plants. This may imply that the males from Bt-RW maize may have been exposed to sublethal doses of Bt toxin as larvae. There were no significant differences between the head capsule width of females coming from Bt-RW maize and non-Bt refuge plants. As season progressed, the average head capsule width decreased regardless of treatment. These findings could be used to improve resistance management, specifically in seed mix refuge system.

Read the abstract at http://onlinelibrary.wiley.com/doi/10.1111/j.1570-7458.2011.01100.x/full.