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We collected developmental, survival, and reproduction data for Aphis fabae Scopoli (Hemiptera: Aphididae) reared on faba bean, Vicia faba L. 'Sevilla' at four constant temperatures (15, 20, 25, and 30°C), 70% relative humidity, and a photoperiod of 16:8 (L:D) h. The highest intrinsic rate of increase (r = 0.4347 d(-1)) and finite rate (λ = 1.5445 d(-1)) were observed at 25°C. The population projection based on the age-stage, two-sex life table quantitatively revealed the growth potential and stage structure of the aphid. We have included the following suggestions to aid researchers in life table studies: 1) The bootstrap method should be used to estimate the variance and SEs of developmental time, survival rate, fecundity, and population parameters. 2) The required number of bootstraps is dependent on the life table data--the higher the variation among individuals, the higher the number of bootstraps should be. In most cases, we suggest that 100,000 bootstraps should be used to obtain a stable estimate of variance and SEs. 3) Computer projection based on the age-stage, two-sex life table should be used to reveal the stage structure during population growth. 4) We used a simple equation based on the total fecundity, survival rate to adult stage, and first reproductive age to detect possible errors in life table parameters. 5) To assist readers in comprehending results, life table studies should include the cohort size, preadult survival rate, number of emerged female adults, mean fecundity, survival and fecundity curves, and population parameters.

Because life tables are capable of providing the most comprehensive description on the survival, stage differentiation, and the reproduction of animal populations, they can be considered as the bases of population ecology and pest management. Researchers concerned with studies involving life tables inevitably face the problem of describing the variabilities that occur in the survival, stage differentiation, and fecundity data. Finding a means to include these variabilities in population projections concerning pest management may be problematic. Henosepilachna vigintioctopunctata (F.) (Coleoptera: Coccinellidae) is a pest of many plant species in Asia, including cultivated crops, ornamentals, and wild plants. The raw life history data (survival, stage differentiation, and fecundity) and consumption rate of both sexes of H. vigintioctopunctata reared on Solanum photeinocarpum Nakamura et Odashima (Solanales: Solanaceae) were collected in the laboratory and analyzed based on the age-stage, two-sex life table theory. The intrinsic rate of increase (r), finite rate of increase (λ), net reproductive rate (R0), mean generation time (T), and net consumption rate (C0) of H. vigintioctopunctata were 0.1312 d-1, 1.1402 d-1, 603.5 offspring, 48.8 d, and 77.8 cm2, respectively. By using the bootstrap technique with 100,000 samples, we demonstrated that the life tables constructed based on the 2.5th and 97.5th percentiles of R0 and λ can be used to describe the variabilities found in the survival and fecundity curves and to project the uncertainty of population growth.

Life table parameters and predation rate of the coccinellid predator Harmonia dimidiata F. fed on Aphis gossypii Glover were determined at 25°C using the age‐stage, two‐sex life table. When the total number of eggs were included in our calculations, the intrinsic rate of increase (r), finite rate (λ), net reproductive rate (R0) and mean generation time (T) for H. dimidiata were 0.1354/day, 1.1450/day, 280.8 offspring and 41.6 day, respectively. These values were significantly different, however, only when viable (=hatchable) H. dimidiata eggs were counted (0.0909/day, 1.0952/day, 67.6 offspring and 46.3 day, respectively). The values obtained using all eggs did not realistically reflect the effect of variable hatch rate and true population parameters of H. dimidiata. We therefore excluded unhatched eggs from our data and demonstrated mathematically that in future demographic studies, it should be a standard procedure to exclude all unhatched eggs when analysing hatch rates that vary with maternal age. A mathematical proof was derived in this study to substantiate this. To observe and quantify variations that occur in the predation rate due to the age and stage of the predator, the daily number of A. gossypii consumed by individual H. dimidiata was analysed using the age‐stage, two‐sex life table. The net predation rate of H. dimidiata on A. gossypii was 14 804 aphids. The transformation rate Qp showed that the predator needs to consume an average of 219.1 aphids to produce one viable egg. The finite predation rate of H. dimidiata was 125.7 when only hatchable eggs were included in the analysis. Because the age‐stage, two‐sex life table takes both of the sexes and the variable predation rate occurring among stages into consideration, it becomes possible to use the population projection to quantify and time biological control procedures.

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