Two-sex life table of Nysius cymoides (Spinola) (Hem.: Lygaeidae) at different photoperiods under laboratory conditions

The life table parameters are the most appropriate index for comparing the fitness of a population to diverse climatic and food-related conditions. In this study, the effect of three photoperiods of 8:16, 12:12 and 16:8 h (L:D) on the life table parameters of Nysius cymoides was studied under laboratory conditions (24±1ºC, 65±5% RH). Data were analyzed based on the age-stage, two-sex life table theory. Immature developmental times of N. cymoides under 12-and 8h photoperiods were significantly shorter than that of treatment with 16h photoperiod. The adult pre-oviposition period (APOP), total pre-oviposition period (TPOP), mean fecundity and adult longevity reared under three photoperiods showed significant differences. The highest and lowest fecundity were 56.65 eggs and 10.1 eggs at 12- and 8h photoperiods, respectively. Intrinsic rates of increase (r) were 0.011 ± 0.004, 0.044 ± 0.003 and 0.039 ± 0.003 (day-1) at 8-, 12- and 16h (L), respectively; and net reproductive rates (R0) were 2.02 ± 0.52, 13.02 ± 2.65 and 11.41± 2.12 (offspring per individual) for the respective treatments. The mean generation times (T) were 56.11 ± 1.26, 57.16 ± 1.53 and 62.32± 1.41 days, at 8-, 12- and 16h (L), respectively. The life expectancy (exj), survival rate (sxj) and cumulative reproductive rate (Rx) at 12-and 16h (L) were higher than those of 8h photoperiod. Generally, 12- and 16h photoperiods were more reasonable for N. cymoides rearing comparing with 8h photoperiod.