Journal of Economic Entomology (2015) 108, 2421-2432

David A. Ingber and Aaron J. Gassmann (2015)
Inheritance and fitness costs of resistance to Cry3Bb1 corn by western corn rootworm (Coleoptera: Chrysomelidae)
Journal of Economic Entomology 108 (5), 2421-2432
Abstract: Transgenic crops that produce insecticidal toxins derived from the bacterium Bacillus thuringiensis (Bt) are widely planted to manage pest insects. One of the primary pests targeted by Bt corn in the United States is western corn rootworm, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae). Cry3Bb1 corn for management of western corn rootworm was commercialized in 2003, and beginning in 2009, populations of western corn rootworm with field-evolved resistance to Cry3Bb1 corn were found in Iowa. Here we quantify the magnitude, inheritance, and fitness costs of resistance to Cry3Bb1 corn in two strains (Hopkinton and Cresco) derived from field populations that evolved resistance to Cry3Bb1 corn. For Hopkinton, we found evidence for complete resistance to Cry3Bb1 corn and nonrecessive inheritance. Additionally, no fitness costs of Cry3Bb1 resistance were detected for Hopkinton. For Cresco, resistance was incomplete and recessive, and we detected fitness costs affecting developmental rate, survival to adulthood, and fecundity. These results suggest that variation may exist among field populations in both the inheritance and accompanying fitness costs of resistance. To the extent that field populations exhibit nonrecessive inheritance and a lack of fitness cost, this will favor more rapid evolution of resistance than would be expected when resistance is functionally recessive and is accompanied by fitness costs.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Aaron J. Gassmann

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
resistance/tolerance/defence of host

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Diabrotica virgifera	Maize/corn (Zea mays)	U.S.A. (mid N)
Bacillus thuringiensis genes in crops (entomopathogen)	Diabrotica virgifera	Maize/corn (Zea mays)	U.S.A. (mid N)
Bacillus thuringiensis Cry3B-toxin (entomopathogen)	Diabrotica virgifera	Maize/corn (Zea mays)	U.S.A. (mid N)