Effects of host plant species on fitness costs of Bt resistance in Helicoverpa armigera (Lepidoptera: Noctuidae)

Bird, Lisa J.; Akhurst, Raymond J.

doi:10.1016/j.biocontrol.2006.11.004

Cited by 79 publications

(86 citation statements)

References 39 publications

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“…Our Þnding here that entomopathogenic nematodes can increase the Þtness cost of Bt resistance complements past work demonstrating ecological factors such as host plants Myers 2005, Bird andAkhurst 2007), competition (Higginson et al 2005, Raymond et al 2005, and viruses (Raymond et al 2007a) can increase the Þtness cost of resistance to Bt. From the perspective of resistance management, these results are important because they point to an opportunity to design refuges to magnify Þtness costs.…”

Section: Discussionsupporting

confidence: 80%

“…2b). Typically, Þtness costs affecting rs individuals are accompanied by lower Þtness for homozygous resistant (rr) individuals (Carriè re et al 2001(Carriè re et al , 2004Bird and Akhurst 2004; Huang et al 2005;Bird and Akhurst 2007), although some studies have reported Þtness costs only affecting rs individuals Wright 2001, Janmaat andMyers 2005). We do not know why a cost affecting only rs individuals was found for SAF97-H4.…”

Section: Discussionmentioning

confidence: 99%

“…This means that some refuges may be better at delaying pest resistance to Bt than other refuges. For example, the host plant on which an insect feeds can alter both the magnitude and dominance of costs (Shirai et al 1998, Carriè re et al 2005, Janmaat and Myers 2005, Janmaat and Myers 2006, Bird and Akhurst 2007, Raymond et al 2007b). In addition, entomopathogenic viruses and nematodes can magnify costs in some cases (Gassmann et al 2006Raymond et al 2007a).…”

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confidence: 99%

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Effects of Pink Bollworm Resistance to Bacillus thuringiensis on Phenoloxidase Activity and Susceptibility to Entomopathogenic Nematodes

Gassmann¹,

Fabrick²,

Sisterson³

et al. 2009

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Widespread planting of crops genetically engineered to produce insecticidal toxins from the bacterium Bacillus thuringiensis (Bt) imposes selection on many key agricultural pests to evolve resistance to Bt. Fitness costs can slow the evolution of Bt resistance. We examined effects of entomopathogenic nematodes on fitness costs of Bt resistance in the pink bollworm,Pectinophora gossypiella (Saunders) (Lepidoptera: Gelechiidae), a major pest of cotton,Gossypium hirsutum L., in the southwestern United States that is currently controlled by transgenic cotton that produces Bt toxin Cry1Ac. We tested whether the entomopathogenic nematodes Steinernema riobrave Cabanillas, Poinar, and Raulston (Rhabditida: Steinernematidae) and Heterorhabditis bacteriophora Poinar (Rhabditida: Heterorhabditidae) affected fitness costs of resistance to Cry1Ac in two laboratory-selected hybrid strains of pink bollworm reared on non-Bt cotton bolls. The nematode S. riobrave imposed a recessive fitness cost for one strain, and H. bacteriophora imposed a fitness cost affecting heterozygous resistant individuals for the other strain. Activity of phenoloxidase, an important component of insects' immune response, did not differ between Bt-resistant and Bt-susceptible families. This suggests phenoloxidase does not affect susceptibility to entomopathogenic nematodes in Bt-resistant pink bollworm. Additionally, phenoloxidase activity does not contribute to Bt resistance, as has been found in some species. We conclude that other mechanisms cause higher nematode-imposed mortality for pink bollworm with Bt resistance genes. Incorporation of nematode-imposed fitness costs into a spatially explicit simulation model suggests that entomopathogenic nematodes in non-Bt refuges could delay resistance by pink bollworm to Bt cotton. RightsWorks produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted. ABSTRACT Widespread planting of crops genetically engineered to produce insecticidal toxins from the bacterium Bacillus thuringiensis (Bt) imposes selection on many key agricultural pests to evolve resistance to Bt. Fitness costs can slow the evolution of Bt resistance. We examined effects of entomopathogenic nematodes on Þtness costs of Bt resistance in the pink bollworm, Pectinophora gossypiella (Saunders) (Lepidoptera: Gelechiidae), a major pest of cotton, Gossypium hirsutum L., in the southwestern United States that is currently controlled by transgenic cotton that produces Bt toxin Cry1Ac. We tested whether the entomopathogenic nematodes Steinernema riobrave Cabanillas, Poinar, and Raulston (Rhabditida: Steinernematidae) and Heterorhabditis bacteriophora Poinar (Rhabditida: Heterorhabditidae) affected Þtness costs of resistance to Cry1Ac in two laboratory-selected hybrid strains of pink bollworm reared on non-Bt cotton bolls. The nematode S. riobrave imposed a recessive Þtness cost for one strain, and H. bacteriophora imposed a Þtness cost affec...

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Section: Discussionsupporting

confidence: 80%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

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Effects of Pink Bollworm Resistance to Bacillus thuringiensis on Phenoloxidase Activity and Susceptibility to Entomopathogenic Nematodes

Gassmann¹,

Fabrick²,

Sisterson³

et al. 2009

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“…Fitness costs can enhance the effectiveness of refuges to delay resistance (Gassmann et al 2009a, Carriè re et al 2010. Evidence from laboratory experiments suggests that Þtness costs of Bt resistance can be increased by several ecological factors including host plant species (Janmaat andMyers 2005, Bird andAkhurst 2007), density (Raymond et al 2005), entomopathogens (Raymond et al 2007, and competition for mates (Higginson et al 2005). In addition, laboratory selection experiments have demonstrated the value of refuges in delaying resistance to Bt (Tang et al 2001).…”

Section: Discussionmentioning

confidence: 99%

Effects of Entomopathogenic Nematodes on Evolution of Pink Bollworm Resistance to Bacillus thuringiensis Toxin Cry1Ac

et al. 2012

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The evolution of resistance by pests can reduce the efficacy of transgenic crops that produce insecticidal toxins from Bacillus thuringiensis (Bt). However, fitness costs may act to delay pest resistance to Bt toxins. Metaanalysis of results from four previous studies revealed that the entomopathogenic nematode Steinernema riobrave (Rhabditida: Steinernematidae) imposed a 20% fitness cost for larvae of pink bollworm, Pectinophora gossypiella (Saunders) (Lepidoptera: Gelechiidae), that were homozygous for resistance to Bt toxin Cry1Ac, but no significant fitness cost was detected for heterozygotes. We conducted greenhouse and laboratory selection experiments to determine whether S. riobrave would delay the evolution of pink bollworm resistance to Cry1Ac. We mimicked the high dose/refuge scenario in the greenhouse with Bt cotton (Gossypium hirsutum L.) plants and refuges of non-Bt cotton plants, and in the laboratory with diet containing Cry1Ac and refuges of untreated diet. In both experiments, half of the replicates were exposed to S. riobrave and half were not. In the greenhouse, S. riobrave did not delay resistance. In the laboratory, S. riobrave delayed resistance after two generations but not after four generations. Simulation modeling showed that an initial resistance allele frequency >0.015 and population bottlenecks can diminish or eliminate the resistance-delaying effects of fitness costs. We hypothesize that these factors may have reduced the resistance-delaying effects of S. riobrave in the selection experiments. The experimental and modeling results suggest that entomopathogenic nematodes could slow the evolution of pest resistance to Bt crops, but only under some conditions. BioOne sees sustainable scholarly publishing as an inherently collaborative enterprise connecting authors, nonprofit publishers, academic institutions, research libraries, and research funders in the common goal of maximizing access to critical research. Effects of Entomopathogenic Nematodes on Evolution of Pink Bollworm Resistance to Bacillus thuringiensis Toxin Cry1AcAuthor (s) ABSTRACT The evolution of resistance by pests can reduce the efÞcacy of transgenic crops that produce insecticidal toxins from Bacillus thuringiensis (Bt). However, Þtness costs may act to delay pest resistance to Bt toxins. Meta-analysis of results from four previous studies revealed that the entomopathogenic nematode Steinernema riobrave (Rhabditida: Steinernematidae) imposed a 20% Þtness cost for larvae of pink bollworm, Pectinophora gossypiella (Saunders) (Lepidoptera: Gelechiidae), that were homozygous for resistance to Bt toxin Cry1Ac, but no signiÞcant Þtness cost was detected for heterozygotes. We conducted greenhouse and laboratory selection experiments to determine whether S. riobrave would delay the evolution of pink bollworm resistance to Cry1Ac. We mimicked the high dose/refuge scenario in the greenhouse with Bt cotton (Gossypium hirsutum L.) plants and refuges of non-Bt cotton plants, and in the laboratory with diet containing Cry1A...

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“…Currently, in a Bt cropping system, the purpose of the refuge is primarily to supply susceptible pests to mate with resistant insects. However, some of the same components of IPM such as biological control and host plant resistance also may act to increase Þtness costs of Bt resistance (Janmaat and Myers 2005, Bird and Akhurst 2007, Raymond et al 2007. The ability of such ecological factors to increase Þtness costs is referred to as ecological negative crossresistance (Pittendrigh et al 2008, Gassmann et al 2009c.…”

Section: Discussionmentioning

confidence: 99%

Effects of Four Nematode Species on Fitness Costs of Pink Bollworm Resistance to Bacillus thuringiensis Toxin Cry1Ac

et al. 2010

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Evolution of resistance by pests can reduce the efficacy of transgenic crops that produce insecticidal toxins from the bacterium Bacillus thuringiensis Berliner (Bt). In conjunction with refuges of non-Bt host plants, fitness costs can delay the evolution of resistance. Furthermore, fitness costs often vary with ecological conditions, suggesting that agricultural landscapes can be manipulated to magnify fitness costs and thereby prolong the efficacy of Bt crops. In the current study, we tested the effects of four species of entomopathogenic nematodes (Steinernematidae and Heterorhabditidae) on the magnitude and dominance of fitness costs of resistance to Bt toxin CrylAc in pink bollworm, Pectinophora gossypiella (Saunders) (Lepidoptera: Gelechiidae). For more than a decade, field populations of pink bollworm in the United States have remained susceptible to Bt cotton Gossypium hirsutum L. producing CrylAc; however, we used laboratory strains that had a mixture of susceptible and resistant individuals. In laboratory experiments, dominant fitness costs were imposed by the nematodeSteinernema riobrave Cabanillas, Poinar, and Raulston but no fitness costs were imposed bySteinernema carpocapsae Weiser, Steinernema sp. (ML18 strain), or Heterorhabditis sonorensis Stock, Rivera-Orduño, and Flores-Lara. In computer simulations, evolution of resistance to CrylAc by pink bollworm was substantially delayed by treating some non-Bt cotton refuge fields with nematodes that imposed a dominant fitness cost, similar to the cost observed in laboratory experiments with S. riobrave. Based on the results here and in related studies, we conclude that entomopathogenic nematodes could bolster insect resistance management, but the success of this approach will depend on selecting the appropriate species of nematode and environment, as fitness costs were magnified by only two of five species evaluated and also depended on environmental factors. RightsWorks produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted. ABSTRACT Evolution of resistance by pests can reduce the efÞcacy of transgenic crops that produce insecticidal toxins from the bacterium Bacillus thuringiensis Berliner (Bt). In conjunction with refuges of non-Bt host plants, Þtness costs can delay the evolution of resistance. Furthermore, Þtness costs often vary with ecological conditions, suggesting that agricultural landscapes can be manipulated to magnify Þtness costs and thereby prolong the efÞcacy of Bt crops. In the current study, we tested the effects of four species of entomopathogenic nematodes (Steinernematidae and Heterorhabditidae) on the magnitude and dominance of Þtness costs of resistance to Bt toxin Cry1Ac in pink bollworm, Pectinophora gossypiella (Saunders) (Lepidoptera: Gelechiidae). For more than a decade, Þeld populations of pink bollworm in the United States have remained susceptible to Bt cotton Gossypium hirsutum L. producing Cry1Ac; however,...

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Effects of host plant species on fitness costs of Bt resistance in Helicoverpa armigera (Lepidoptera: Noctuidae)

Cited by 79 publications

References 39 publications

Effects of Pink Bollworm Resistance to <I>Bacillus thuringiensis</I> on Phenoloxidase Activity and Susceptibility to Entomopathogenic Nematodes

Effects of Pink Bollworm Resistance to <I>Bacillus thuringiensis</I> on Phenoloxidase Activity and Susceptibility to Entomopathogenic Nematodes

Effects of Entomopathogenic Nematodes on Evolution of Pink Bollworm Resistance to <I>Bacillus thuringiensis</I> Toxin Cry1Ac

Effects of Four Nematode Species on Fitness Costs of Pink Bollworm Resistance to Bacillus thuringiensis Toxin Cry1Ac

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