Temperature-Dependent Development, Survival, and Population Growth of Novius penicillioides: Implications for Biological Control of Icerya jacobsoni Under Climate Warming

The cottony cushion scale Icerya jacobsoni is a serious pest of agriculture and forestry, and the ladybird Novius penicillioides is an important predator of this pest. Temperature strongly affects insect development and reproduction, but the thermal biology of N. penicillioides remains unknown. Here, N. penicillioides was reared at six constant temperatures (17–32 °C) for immature development and survival, and at five temperatures (17–29 °C) for adult reproduction and life table analysis. Developmental duration decreased with rising temperature, whereas survival and fecundity were highest at 20–26 °C. Egg hatch rate fell to 0.25 at 32 °C, and fecundity at 29 °C was 84.3% lower than at 20 °C. The intrinsic rate of increase and finite rate of increase peaked at 26 °C (0.091 and 1.095), identifying this as the optimal temperature for population growth. The lower developmental threshold for the egg-to-adult period was 3.76 °C, with a degree-day requirement of 476.19 degree-days. At 32 °C, only 18% of immatures reached adulthood and the few surviving females failed to reproduce, indicating that the upper thermal limit for population growth lies between 29 and 32 °C. Given that natural enemies often have lower optimal temperatures than their prey, a thermal asymmetry may exist between N. penicillioides and I. jacobsoni, and continued warming could reduce its summer control efficacy. These findings provide key thermal parameters for optimizing mass rearing and field release strategies of this predator.