title: Reproductive Cost Associated With Juvenile Hormone in Bt-Resistant Strains of Helicoverpa armigera (Lepidoptera: Noctuidae).
abstract: Transgenic Bacillus thuringiensis (Bt) crops are increasingly significant in pest control, but resistance development of target pests is a major issue in the sustainable deployment of Bt crops. The fitness cost of resistance in target pests is regarded as one of the main factors delaying resistance when adopting the refuge strategy. In this study, we compared the life-history traits of three independent sets of Helicoverpa armigera (Hübner, 1809) adults, of each there were a susceptible population and a Cry1Ac-resistant population derived by selection from it. Confirming to the previous studies, resistant individuals exhibited fewer progeny, less fecundity, lower egg hatching rate, and longer adult longevity. And poor fecundity in resistant strains was associated with the decline of the mature follicular amount, the ovarian weight ratio, and the length of the longest ovarian tubule. Interestingly, the juvenile hormone (JH) level appeared higher in resistant strains relative to susceptible strains. Application of methoprene (JH analogue) in vivo was effective in reducing fecundity and hatchability with the up-regulation of detected JH titer. These results suggested that resistance against Bt toxin reduced the reproductive capacity of H. armigera, and JH level is affected in the tradeoff between reproductive capacity and Bt resistance.
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 (zhangwanna880210@yeah.net; wangbingjie@163.com; chenl1992@163.com; MMK@yahoo.com; yhlu@163.com; 498775644@qq.com; yyguo@ippcaas.cn).
authors.forename: W N
authors.initials: WN
authors.lastname: Zhang
authors.affiliation: Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou 310008, China (president114@163.com).
authors.forename: L
authors.initials: L
authors.lastname: Ma
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 (zhangwanna880210@yeah.net; wangbingjie@163.com; chenl1992@163.com; MMK@yahoo.com; yhlu@163.com; 498775644@qq.com; yyguo@ippcaas.cn).
authors.forename: B J
authors.initials: BJ
authors.lastname: Wang
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 (zhangwanna880210@yeah.net; wangbingjie@163.com; chenl1992@163.com; MMK@yahoo.com; yhlu@163.com; 498775644@qq.com; yyguo@ippcaas.cn).
authors.forename: L
authors.initials: L
authors.lastname: Chen
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 (zhangwanna880210@yeah.net; wangbingjie@163.com; chenl1992@163.com; MMK@yahoo.com; yhlu@163.com; 498775644@qq.com; yyguo@ippcaas.cn).
authors.forename: M M
authors.initials: MM
authors.lastname: Khaing
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 (zhangwanna880210@yeah.net; wangbingjie@163.com; chenl1992@163.com; MMK@yahoo.com; yhlu@163.com; 498775644@qq.com; yyguo@ippcaas.cn).
authors.forename: Y H
authors.initials: YH
authors.lastname: Lu
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 (zhangwanna880210@yeah.net; wangbingjie@163.com; chenl1992@163.com; MMK@yahoo.com; yhlu@163.com; 498775644@qq.com; yyguo@ippcaas.cn) 498775644@qq.com.
authors.forename: G M
authors.initials: GM
authors.lastname: Liang
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 (zhangwanna880210@yeah.net; wangbingjie@163.com; chenl1992@163.com; MMK@yahoo.com; yhlu@163.com; 498775644@qq.com; yyguo@ippcaas.cn).
authors.forename: Y Y
authors.initials: YY
authors.lastname: Guo
mesh_terms: D000818:Animals; D001413:Bacillus thuringiensis / Q000737:chemistry; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000494:pharmacology*; D004731:Endotoxins / Q000494:pharmacology*; D005260:Female; D005298:Fertility / Q000187:drug effects; D006460:Hemolysin Proteins / Q000494:pharmacology*; D007305:Insecticide Resistance; D007605:Juvenile Hormones / Q000494:pharmacology*; D008297:Male; D009036:Moths / Q000187:drug effects* / Q000502:physiology; D010572:Pest Control, Biological; D012098:Reproduction / Q000187:drug effects
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004731:Endotoxins; D006460:Hemolysin Proteins; D007605:Juvenile Hormones; C030956:insecticidal crystal protein, Bacillus Thuringiensis
keywords: Bacillus thuringiensis; Helicoverpa armigera; fitness cost; juvenile hormone; reproduction