Abstract: 【Aim】 Brithys crini (Fabricius) mainly feeds on Amaryllidaceae plant, including Zephyranthes candida. Previous research showed that photoperiod has significant effects on the circadian rhythm of mating and oviposition, mating percentage and the number of eggs laid of B. crini. This study aims to investigate the effects of intermittent light length, the position of dark period and non-24 h light-dark cycle on its mating and oviposition. 【Methods】 The mating and oviposition were observed in intermittent light lengths (20, 10, 5, 1 and 0 min), the position of dark period (D_{10: 00 -22: 00}, D_{12: 00 -24: 00}, D_{14: 00 - 02: 00} and D_{16: 00 -04: 00}) and non-24 h light-dark cycle (4L∶4D, 8L∶8D, 24L∶24D and 48L∶48D) under the climate cabinet conditions (white fluorescent light, light intensity about 500 lx). 【Results】 When intermittent light lengths were 20, 10, 5, 1 and 0 min, the numbers of mated adults were 0, 3, 10, 14 and 11, and the numbers of paired adults were 25, 29, 31, 39 and 26, respectively. The numbers of mated adults in 20 and 10 min groups were significantly different from that of the control group (0 min). The numbers of eggs laid per mated female were insignificantly different among groups (354.67, 322.30, 339.57 and 310.45 eggs for 10, 5, 1 and 0 min group, respectively). The numbers of mated adults were 13, 18, 15 and 12, and the numbers of paired adults were 16, 19, 17 and 16 in D_{10: 00-22: 00}, D_{12: 00-24: 00}, D_{14: 00-02: 00} and D_{16: 00-04: 00} groups, respectively, and there was no significant difference among treatment groups. The number of eggs laid per mated female was insignificantly different among treatment groups (516.15, 527.28, 495.53 and 458.50 eggs in D_{10: 00-22: 00}, D_{12: 00-24: 00}, D_{14: 00-02: 00} and D_{16: 00-04: 00} groups, respectively). The initiation time and peak time of mating and oviposition varied with the position of dark period. The numbers of mated adults were 16, 15, 14 and 14, and the numbers of paired adults were 18, 16, 14 and 16 in 4L∶4D, 8L∶8D, 24L∶24D and 48L∶48D groups, respectively, and there was no significant difference among treatment groups. The number of eggs laid per mated female was significantly different among groups (590.56, 559.67, 497.21 and 419.29 eggs in 4L∶4D, 8L∶8D, 24L∶24D and 48L∶48D groups, respectively). 【Conclusion】 These results reveal that the mating and oviposition behaviors of B. crini occur mainly in the dark period. The adults would not mate when the dark period is shorter than 40 min. The position and length of dark period have influences on the mating and oviposition of B. crini.

Key words: Brithys crini, light conditions, photoperiod, mating, oviposition, circadian rhythm