Abstract: 【Aim】 The green lacewing, Chrysopa pallens (Rambur), is an important natural enemy insect and enters diapause as prepupa in winter. This study aims to understand the effects of photoperiod and temperature on diapause termination and post-diapause development and reproduction of C. pallens. 【Methods】 The diapause termination and post-diapause biology including pupal duration, pupal survival rate, adult fresh weight, adult longevity, preoviposition period and number of eggs laid per female of C. pallens were observed after the diapaused prepupae were treated under different combinations of temperatures (22℃ and 25℃) and photoperiods (15L∶9D and 9L∶15D). The effects of chilling at 5℃ on diapause termination, and diapause duration on the post-diapause development and reproduction of C. pallens were also investigated. 【Results】 The prepupal duration under the photoperiods of 15L∶9D and 9L∶15D at 25℃ (50.09 and 49.47 d, respectively) was significantly shorter than those at 22℃ (80.80 and 82.20 d, respectively). The chilling treatment at 5℃ prolonged the prepupal duration extremely significantly (P<0.01), and deceased the individual difference of prepupal duration. At 22℃, compared with the non-diapause prepupa, for the diapaused prepupa the survival rate was significantly decreased, the pupal duration and preoviposition period were significantly prolonged, the female adult longevity was significantly shortened, and the adult fresh weight and the number of eggs laid per female were significantly decreased. The diapause duration of C. pallens was 50-170 d at 22℃ under a photoperiod of 15L∶9D, and the post diapause development was affected, with the pupal duration gradually prolonged, the adult fresh weight decreasing, and the male adult longevity initially increasing and then decreasing, but with no significant differences in the pupal survival rate, female adult longevity, preoviposition period and number of eggs laid per female. 【Conclusion】 Under the experimental conditions, the tested photoperiods have no significant effects on the diapause termination and post-diapause development and reproduction in C. pallens, while temperature is the key factor to regulate diapause development and reproduction. Higher temperature promotes the termination of diapause, and chilling can synchronize population diapause development. There is reproduction cost in diapaused C. pallens, and diapause duration affects some of its post-diapause biological characteristics.

Key words: Chrysopa pallens, photoperiod, temperature, diapause duration, post diapause development, reproduction