The impact of strain diversity and mixed infections on the evolution of resistance to Bacillus thuringiensis

Raymond, Ben, Wright, Denis J, Crickmore, Neil and Bonsall, Michael B (2013) The impact of strain diversity and mixed infections on the evolution of resistance to Bacillus thuringiensis. Proceedings of the Royal Society B: Biological Sciences, 280 (1769). p. 20131497. ISSN 0962-8452

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Pesticide mixtures can reduce the rate at which insects evolve pesticide resistance. However, with live biopesticides such as the naturally abundant pathogen Bacillus thuringiensis (Bt), a range of additional biological considerations might affect the evolution of resistance. These can include ecological interactions in mixed infections, the different rates of transmission post-application and the impact of the native biodiversity on the frequency of mixed infections. Using multi-generation selection experiments, we tested how applications of single and mixed strains of Bt from diverse sources (natural isolates and biopesticides) affected the evolution of resistance in the diamondback moth, Plutella xylostella, to a focal strain. There was no significant difference in the rate of evolution of resistance between single and mixed-strain applications although the latter did result in lower insect populations. The relative survivorship of Bt-resistant genotypes was higher in the mixed-strain treatment, in part owing to elevated mortality of susceptible larvae in mixtures. Resistance evolved more quickly with treatments that contained natural isolates, and biological differences in transmission rate may have contributed to this. Our data indicate that the use of mixtures can have unexpected consequences on the fitness of resistant and susceptible insects.

Item Type: Article
Schools and Departments: School of Life Sciences > Biochemistry
Subjects: Q Science > QR Microbiology > QR0075 Bacteria
Depositing User: Neil Crickmore
Date Deposited: 05 Sep 2014 14:02
Last Modified: 05 Sep 2014 14:02
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