Fitness Costs of Resistance to Bt Cotton Linked with Increased Gossypol Content in Pink Bollworm Larvae
Author Information
Author(s): Williams Jennifer L., Ellers-Kirk Christa, Orth Robert G., Gassmann Aaron J., Head Graham, Tabashnik Bruce E., Carrière Yves
Primary Institution: Department of Entomology, University of Arizona
Hypothesis
Fitness costs of resistance to Bt cotton in pink bollworm are associated with increased concentration in larvae of a plant defensive chemical, gossypol.
Conclusion
Higher larval gossypol content was associated with a higher fitness cost affecting larval growth.
Supporting Evidence
- Resistance to Cry1Ac cotton is associated with mutations altering cadherin proteins in pink bollworm.
- Gossypol concentration was higher in larvae with cadherin resistance alleles than in those without.
- Adding gossypol to the larval diet decreased larval weight and survival.
- The fitness cost affecting larval growth increased as the gossypol concentration of larvae increased.
Takeaway
When pink bollworm larvae eat cotton with a chemical called gossypol, those with resistance genes have more gossypol and grow worse than those without the genes.
Methodology
The study involved feeding pink bollworm larvae with diets containing gossypol and measuring their weight and survival rates.
Potential Biases
Potential bias due to the commercial affiliation of some authors with Monsanto.
Limitations
The study did not measure the long-term effects of gossypol on survival or reproduction.
Participant Demographics
Pink bollworm larvae from three strains derived from a single collection in Arizona.
Statistical Information
P-Value
p<0.0001
Confidence Interval
Not specified
Statistical Significance
p<0.0001
Digital Object Identifier (DOI)
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