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The effects of imidacloprid, propargite, and pymetrozine on the common green lacewing, Chrysoperla carnea (Stephens) were investigated in the laboratory, using the IOBC-system and the life table response experiment. Residual glass plate bioassays were carried out using two-day-old larvae at the Iranian maximum field recommended rate of each commonly used pesticide. All three tested pesticides produced significant adverse effects on pre-imaginal survival (p < 0.01). Imidacloprid had no significant effect on fecundity, but propargite and pymetrozin caused significant reductions (p < 0.05). According to the IOBC classification, imidacloprid was found to be harmless (E = 27.44%); propargite (E = 49.78%) and pymetrozine (E = 66.9%) were slightly harmful. Life table assays revealed that imidacloprid and propargite had no significant effects on the intrinsic rate of natural increase, while pymetrozine caused a 34% reduction in r m value (p < 0.05). Propargite was non-toxic to C. carnea under the tested conditions. In the case of imidacloprid, using a glass plate as test substrate led to underestimation of its effects. The life table assay showed more adverse effects of pymetrozine than the IOBC method.

Life tables of twospotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), were studied on leaf discs and whole leaves of the common bean plant, Phaseolus vulgaris L. Data were analyzed based on the age-stage, two-sex life table theory. Durations of deutonymph stage, total preadult stage, and preoviposition period of mites reared on whole leaves (1.22, 7.6, and 0.29 d, respectively) were significantly shorter than those reared on leaf discs (1.73, 8.2, and 0.89 d, respectively). The lifetime fecundities were 22.81 and 12.05 offspring on whole leaves and leaf discs, respectively. Although hooked trichomes on the lower surface of the bean leaf contribute to adult mortality, spider mites successfully survive and reproduce on bean plants. The intrinsic rate of increase on whole leaves (0.235 d(-1)) was higher than that on leaf discs (0.159 d(-1). Higher intrinsic rate and fecundity found in mites reared on whole leaves may be due to the higher nutritional quality of whole leaves over leaf discs. We suggest that whole leaves should be used in future studies to better simulate realistic life history characteristics. The advantages of using age-stage, two-sex life tables over female age-specific life tables are discussed.

The life table and parasitism rate of Diadegma insulare (Cresson) (Hymenoptera: Ichneumonidae), a larval parasitoid of the diamondback moth Plutella xylostella (L.) (Lepidoptera: Plutellidae), were studied at 25 ± 1°C, 65 ± 10% RH, and a photoperiod of 16:8 (L: D) h. The data were analyzed based on the age-stage, two-sex life table theory. Because the sex ratio of offspring varies with the age of the female parent, we used only female offspring to calculate the intrinsic rate of increase (r), finite rate of increase (λ), net reproductive rate (R0), and mean generation time (T) by using the jackknife technique, the values of which were 0.18407 d-1, 1.2021 d-1, 17.94 offspring, and 15.69 d, respectively. We also calculated these parameters by using bootstrap technique. They were not significantly different from those estimated by using the jackknife technique. We included both male and female offspring in the calculation of the parasitism rate. The net parasitism rate (C0) was 42.63 aphids. Moreover, population projection showed differences between simulated population based on total offspring and female offspring. Because both the offspring sex ratio and the parasitism rate depend on female age, it is necessary to use the age-stage, two-sex life table for a correct analysis. Frequency of the net reproductive rate estimated by using bootstrap technique fit normal distribution well, whereas frequency data estimated by using jackknife technique failed the normality test. We suggest that the jackknife technique should not be used for the estimation of population parameters.