Assessment of fitness costs in Cry3Bb1-resistant and susceptible western corn rootworm (Coleoptera: Chrysomelidae) laboratory colonies
Article first published online: 1 FEB 2012
Published 2012. This article is a U.S. Government work and is in the public domain in the USA
Journal of Applied Entomology
Volume 136, Issue 10, pages 730–740, December 2012
How to Cite
Oswald, K. J., French, B. W., Nielson, C. and Bagley, M. (2012), Assessment of fitness costs in Cry3Bb1-resistant and susceptible western corn rootworm (Coleoptera: Chrysomelidae) laboratory colonies. Journal of Applied Entomology, 136: 730–740. doi: 10.1111/j.1439-0418.2012.01704.x
- Issue published online: 6 DEC 2012
- Article first published online: 1 FEB 2012
- Received: September 12, 2011; accepted: December 28, 2011.
- Bacillus thuringiensis resistance;
- fitness costs;
- western corn rootworm
Abstract Maize production in the United States is dominated by plants genetically modified with transgenes from Bacillus thuringiensis (Bt). Cry3Bb delta endotoxins expressed by Bt maize specifically target corn rootworms (genus Diabrotica) and have proven highly efficacious. However, development of resistance to Bt maize, especially among western corn rootworm (Diabrotica virgifera virgifera) populations, poses a significant threat to the future viability of this pest control biotechnology. The structured refuge insect resistance management (IRM) strategy implemented in the United States for Bt maize adopts a conservative approach to managing resistance by assuming no fitness costs of Bt resistance, even though these trade-offs strongly influence the dynamics of Bt resistance within numerous agricultural pest species. To investigate the effects of Bt resistance on fitness components of western corn rootworm, we compared survivorship, fecundity and viability of five Bt-resistant laboratory lines reared on MON863 (YieldGard Rootworm), a Bt maize product that expresses Cry3Bb1 delta endotoxin, and on its non-transgenic isoline. Analysis of performance on the isoline maize demonstrated no fitness costs associated with Bt resistance. In fact, resistant lines emerged approximately 2–3 days earlier than control lines when reared on both MON863 and the isoline, indicating that selection for Bt resistance resulted in a general increase in the rate of larval development. In addition, resistant lines reared on Bt maize displayed higher fecundity than those reared on the isoline, which may have significant management implications. These data will be valuable for formulating improved IRM strategies for a principal agricultural pest of maize.