Proceedings of the Royal Society of London. Series B, Biological Sciences (2005) 272, 1519-1524

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Ben Raymond, Ali H. Sayyed and Denis J. Wright (2005)
Genes and environment interact to determine the fitness costs of resistance to Bacillus thuringiensis
Proceedings of the Royal Society of London. Series B, Biological Sciences 272 (1571), 1519-1524
Abstract: Genes which provide resistance to novel challenges such as pesticides, toxins or pathogens often impose fitness costs on individuals with a resistant phenotype. Studies of resistance to Bacillus thuringiensis and its insecticidal Cry toxins indicate that fitness costs may be variable and cryptic. Using two field populations (Karak and Serd4) of the diamondback moth, Plutella xylostella, we tested the hypothesis that the costs associated with resistance to the B. thuringiensis toxin Cry1Ac would be evident when insects were grown under poor environmental conditions, namely limited or poor quality resources. On a poor quality resource, a cultivar of Brassica oleracea var. capitata with varietal resistance to P. xylostella, only one resistant population, Karak, showed reduced fitness. Conversely, when we limited a high quality resource, Brassica pekinensis, by imposing larval competition, only resistant Serd4 insects had reduced survival at high larval densities. Furthermore, Cry1Ac resistance in Serd4 insects declined when reared at high larval densities while resistance at low densities fluctuated but did not decline significantly. These results confirm the hypothesis that resistance costs can appear under stressful conditions and demonstrate that the fitness cost of resistance to Bacillus thuringiensis can depend on the particular interaction between genes and the environment.
Link to article at publishers website
Database assignments for author(s): Ben Raymond

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

Pest and/or beneficial records:

Beneficial Pest/Disease/Weed Crop/Product Country Quarant.

Plutella xylostella Cabbage (Brassica oleracea)
Bacillus thuringiensis Cry1A-toxin (entomopathogen) Plutella xylostella Cabbage (Brassica oleracea)