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Relative fitness and stability of resistance in a near‐isogenic strain of indoxacarb resistant Helicoverpa armigera (Lepidoptera: Noctuidae)
Author(s) -
Bird Lisa J,
Drynan Linda J,
Walker Paul W
Publication year - 2020
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.5962
Subject(s) - biology , indoxacarb , fecundity , backcrossing , helicoverpa armigera , diapause , noctuidae , strain (injury) , population , lepidoptera genitalia , genetics , toxicology , botany , agronomy , larva , pesticide , demography , gene , anatomy , sociology
BACKGROUND A strain of Helicoverpa armigera with 171‐fold resistance to indoxacarb was introgressed with a susceptible strain by serial backcrossing and reselection with indoxacarb resulting in the creation of the near‐isogenic GY7‐39BC4 strain. Fitness was compared on artificial diet under diapause and non‐diapause conditions in resistant, susceptible and F 1 progeny from a reciprocal backcross of the two strains using life history trait analyses. Selection experiments were used to determine stability of resistance. RESULTS There were no significant differences between strains in survival, female fertility or realized fecundity. A comparison of the intrinsic rate of population increase showed similar relative fitness between strains. Lower male fertility and male longevity in the resistant strain and one of the F1 strains compared with the susceptible strain suggests small non‐recessive costs may be associated with male reproductive capacity in individuals with indoxacarb resistance alleles. However, there was no significant decline in resistance in the GY7‐39 strain when reared in the absence of insecticide for five generations. Following an artificially induced diapause, survival was reduced by 52% and pupal weights were significantly lower in the resistant strain compared with the susceptible strain. CONCLUSIONS These results suggest indoxacarb resistance does not confer a major fitness cost under standard laboratory conditions. However, a survival cost associated with overwintering highlights the imperative for adoption of management strategies in northern regions of Australia where a winter diapause does not occur. © 2020 Society of Chemical Industry