Abstract
Life table data for Helicoverpa armigera (Hubner) that were reared on an artificial diet at 29°C were collected in the laboratory and analyzed using the age-stage, two-sex life table. The age-specific fecundity was calculated based on the number of eggs hatched in order to accurately reveal the biological characteristics of H. armigera by capturing the variation in hatch rate with female age. The intrinsic rate of increase (r), finite rate (λ) and mean generation time (T), net reproductive rate (R0), and gross reproductive rate (GRR) of H. armigera were 0.1029 d^(-1), 1.1083 d^(-1), 36.7 d, 40.2 offspring and 68.6 offspring, respectively. The relationship between the net reproductive rate and the mean female fecundity was consistent with theoretical proof. This study indicated that a 29°C temperature regime is not as conducive as a 25°C temperature regime for rearing H. armigera on an artificial diet in the laboratory. The standard errors of the life table parameters were estimated using both the jackknife and bootstrap techniques. The frequency distribution of the sample means obtained by the jackknife technique failed the normality test, while the bootstrap results fitted the normal distribution well. Because the jackknife technique generates biologically meaningless zeros for the net reproductive rate, it should not be used for estimating the standard error of the net reproductive rate. The application of the jackknife technique in estimating other population parameters requires further examination. For a correct estimation of the intrinsic rate, the age index and the exponent in the Euler-Lotka equation should be chosen according to the definition of the age-specific survival rate (lx) and the age-specific fecundity (mx). Because the age-stage, two-sex life table accurately describes the survival, development, stage differentiation, and reproduction of insects, we suggest it should be used in the analysis of insect demography.
Published Version
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