Effects of Entomopathogens on Mortality of Western Corn Rootworm (Coleoptera: Chrysomelidae) and Fitness Costs of Resistance to Cry3Bb1 Maize

2014 ◽  
Vol 107 (1) ◽  
pp. 352-360 ◽  
Author(s):  
Amanda M. Hoffmann ◽  
B. Wade French ◽  
Stefan T. Jaronski ◽  
Aaron J. Gassmann
Keyword(s):  
Western Corn Rootworm ◽  
Corn Rootworm ◽  
Fitness Costs

scholarly journals Inheritance and Fitness Costs of Cry3Bb1 Resistance in Diapausing Field Strains of Western Corn Rootworm (Coleoptera: Chrysomelidae)

2020 ◽  
Vol 113 (6) ◽  
pp. 2873-2882
Author(s):  
Ram B Shrestha ◽  
Aaron J Gassmann
Keyword(s):  
Developmental Rate ◽  
Diabrotica Virgifera Virgifera ◽  
Dry Mass ◽  
Western Corn Rootworm ◽  
Corn Rootworm ◽  
Adult Size ◽  
Inheritance Of Resistance ◽  
Diabrotica Virgifera ◽  
Fitness Costs ◽  
Diabrotica Virgifera Virgifera Leconte

Abstract Field-evolved resistance to Cry3Bb1 corn by western corn rootworm, Diabrotica virgifera virgifera LeConte (Colleoptera: Chrysomellidae), has been reported in field populations in Iowa, Illinois, Nebraska, and Minnesota. Inheritance and fitness costs associated with Cry3Bb1 resistance have been determined for non-diapausing laboratory strains of western corn rootworm with either laboratory-selected resistance or field-derived resistance. However, information on inheritance and fitness costs of Cry3Bb1 resistance in the diapausing field populations is lacking. In this study, we determined the inheritance of Cry3Bb1 resistance for four diapausing field strains of western corn rootworm using plant-based bioassays. We also determined the fitness costs for eight diapausing field populations in a greenhouse experiment. We found that Cry3Bb1 resistance was an autosomal trait and that the inheritance of resistance was mostly non-recessive; however, there was some variation in the dominance of Cry3Bb1 resistance. We did not find evidence of fitness costs affecting survival to adulthood, developmental rate, or adult dry mass. However, we did detect a fitness cost affecting adult size. The results of this study will add to the current understanding of field-evolved resistance to Cry3Bb1 corn by western corn rootworm and help in developing better strategies to manage resistance.

scholarly journals Adaptation by Western Corn Rootworm (Coleoptera: Chrysomelidae) to Bt Maize: Inheritance, Fitness Costs, and Feeding Preference

2012 ◽  
Vol 105 (4) ◽  
pp. 1407-1418 ◽  
Author(s):  
Jennifer L. Petzold-Maxwell ◽  
Ximena Cibils-Stewart ◽  
B. Wade French ◽  
Aaron J. Gassmann
Keyword(s):  
Feeding Preference ◽  
Western Corn Rootworm ◽  
Corn Rootworm ◽  
Fitness Costs ◽  
Bt Maize

scholarly journals Applying a Selection Experiment to Test for Fitness Costs of Bt Resistance in Western Corn Rootworm (Coleoptera: Chrysomelidae) and the Effect of Density on Fitness Costs

2020 ◽  
Vol 113 (5) ◽  
pp. 2473-2479
Author(s):  
Coy R St. Clair ◽  
Eric H Clifton ◽  
Mike W Dunbar ◽  
Kenneth E Masloski ◽  
Aubrey R Paolino ◽  
...  
Keyword(s):  
Larval Density ◽  
Ecological Factors ◽  
Diabrotica Virgifera Virgifera ◽  
Western Corn Rootworm ◽  
Larval Rearing ◽  
Corn Rootworm ◽  
Fitness Costs ◽  
Bt Resistance ◽  
Rearing Density ◽  
Bacterium Bacillus

Abstract Western corn rootworm, Diabrotica virgifera virgifera LeConte, is a serious pest of corn and is often managed with transgenic corn producing insecticidal toxins from the bacterium Bacillus thuringiensis (Bt). This pest has developed field-evolved resistance to all commercially available Bt traits, beginning with Cry3Bb1 in 2009. Fitness costs may accompany Bt resistance, where individuals with alleles for Bt resistance have reduced fitness on non-Bt corn compared to Bt-susceptible individuals. In conjunction with non-Bt refuges, fitness costs can delay the evolution of Bt resistance. Importantly, ecological factors may affect the presence and magnitude of fitness costs. For western corn rootworm, available data suggest that fitness costs of Bt resistance may be present in some cases. Using two Cry3Bb1-resistant western corn rootworm strains (Hopkinton and Cresco), a fitness-cost experiment was performed by rearing rootworm in the absence of Bt for six generations to test for fitness costs of Cry3Bb1 resistance and the effect of larval rearing density on fitness costs. Fitness costs were detected for both strains; however, strains were still resistant to Cry3Bb1 corn at the end of the experiment. Cresco experienced a greater loss of resistance at low versus high density, but no effect of density was detected in Hopkinton. Our study shows that fitness costs can accompany Bt resistance in western corn rootworm and may be more pronounced under low larval density. Even though fitness costs were present, it appears that rootworm populations may remain resistant to Cry3Bb1 corn for years after resistance has evolved.

scholarly journals Fitness costs of resistance to Cry3Bb1 maize by western corn rootworm

2015 ◽  
Vol 139 (6) ◽  
pp. 403-415 ◽  
Author(s):  
A. M. Hoffmann ◽  
B. W. French ◽  
R. L. Hellmich ◽  
N. Lauter ◽  
A. J. Gassmann
Keyword(s):  
Western Corn Rootworm ◽  
Corn Rootworm ◽  
Fitness Costs
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