title: Quantitative analysis of fitness costs associated with the development of resistance to the Bt toxin Cry1Ac in Helicoverpa armigera.
abstract: Transgenic Bacillus thuringiensis (Bt) crops play an increasing role in pest control, and resistance management is a major issue in large-scale cultivation of Bt crops. The fitness cost of resistance in targeted pests is considered to be one of the main factors delaying resistance when using the refuge strategy. By comparing 10 resistant Helicoverpa armigera (Hubner) strains, showing various resistance levels to Bt toxin (Cry1Ac), to a susceptible strain, we showed an increasing fitness cost corresponding with increasing levels of resistance. The relationship between overall fitness cost C and the resistance ratio Rr could be described by C = 24.47/(1 + exp([1.57 - Log10Rr]/0.2)). This model predicted that the maximum overall fitness cost would be ~24% (± 5.22) in the strains with the highest resistance level. The overall fitness cost was closely linked to egg hatching rate, fecundity, emergence rate, larval survival rate, and developmental duration of adults. Among fitness components measured, fecundity was the most sensitive trait linked to the resistance selection. To integrate the results into simulation models would be valuable in evaluating how variation in fitness cost may influence the development of resistance in pest populations, thus helping to develop enhanced refuge strategies.
authors.affiliation: 1] State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China [2].
authors.forename: Guangchun
authors.initials: G
authors.lastname: Cao
authors.affiliation: 1] Institute of Plant Protection, Henan Academy of Agricultural Sciences, Zhengzhou, 450002, China [2].
authors.forename: Hongqiang
authors.initials: H
authors.lastname: Feng
authors.affiliation: State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Guo
authors.affiliation: State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
authors.forename: Kongming
authors.initials: K
authors.lastname: Wu
authors.affiliation: Department of Entomology, University of Arizona, 85721 Tucson, AZ, USA.
authors.forename: Xianchun
authors.initials: X
authors.lastname: Li
authors.affiliation: State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
authors.forename: Gemei
authors.initials: G
authors.lastname: Liang
authors.affiliation: French National Institute for Agricultural Research (INRA), UMR1355-ISA, 06903 Sophia-Antipolis, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Desneux
mesh_terms: D000818:Animals; D001413:Bacillus thuringiensis / Q000235:genetics*; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000235:genetics*; D004731:Endotoxins / Q000235:genetics*; D006460:Hemolysin Proteins / Q000235:genetics*; D007305:Insecticide Resistance / Q000235:genetics*; D007814:Larva / Q000382:microbiology; D007915:Lepidoptera / Q000382:microbiology*; D009036:Moths / Q000382:microbiology*; D030821:Plants, Genetically Modified / Q000382:microbiology*; D014118:Toxins, Biological / Q000235:genetics
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004731:Endotoxins; D006460:Hemolysin Proteins; D014118:Toxins, Biological; C030956:insecticidal crystal protein, Bacillus Thuringiensis