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Fitness costs of reproductive capacity and ovarian development in a Bt ‐resistant strain of the cotton bollworm Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae)
Author(s) -
Zhang Wanna,
Ma Long,
Zhong Feng,
Wang Yanan,
Guo Yuyuan,
Lu Yanhui,
Liang Gemei
Publication year - 2015
Publication title -
pest management science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.296
H-Index - 125
eISSN - 1526-4998
pISSN - 1526-498X
DOI - 10.1002/ps.3900
Subject(s) - cry1ac , helicoverpa armigera , fecundity , bacillus thuringiensis , biology , noctuidae , lepidoptera genitalia , strain (injury) , botany , microbiology and biotechnology , veterinary medicine , horticulture , genetically modified crops , bacteria , genetics , transgene , population , medicine , demography , anatomy , sociology , gene
BACKGROUND The cotton bollworm Helicoverpa armigera has developed resistance to the insecticidal Cry1Ac toxins produced by Bacillus thuringiensis ( Bt ) in China. To gain a better understanding of the fitness cost associated with resistance evolution, reproductive capacities and ovarian development were examined in four strains of H. armigera : a Cry1Ac ‐susceptible strain ( 96S ); a Cry1Ac ‐resistant strain fed on an artificial diet with Cry1Ac toxin for 135 generations ( BtR ); two strains derived from BtR : a strain grown without Cry1Ac selection for 38 generations ( CK1 ) and a strain grown for one generation without Cry1Ac selection ( CK2 ). RESULTS Strains 96S and CK1 had similar reproductive capacity and Cry1Ac susceptibility. Compared with the 96S and CK1 strains, the fecundity and hatching rate of CK2 were respectively more than 30% and 50% lower. Moreover, the number of eggs laid by BtR was significantly lower than the number of eggs laid by 96S and CK1 , but higher than the number of eggs laid by CK2 . In accordance with the differences in reproductive capacity, ovarian development in CK2 and BtR was significantly delayed. CONCLUSION These results indicated that there was a fitness cost in the reproductive physiology in the resistant strains. Reversion to susceptibility to the Bt Cry‐toxin in the resistant CK1 strain was associated with an increase in reproductive capacity. © 2014 Society of Chemical Industry