变化光周期对丽斗蟋(Velarifictonus ornatus)若虫发育的影响

Effects of changing photoperiod on nymphal development in a cricket(Velarifictonus ornatus)

为弄清湖南株洲丽斗蟋若虫的季节适应策略,研究了恒定及变化光周期对其若虫发育的调控。结果表明,丽斗蟋若虫发育明显受变化光周期的影响。25℃温度条件下,3个光周期条件下的若虫发育都较慢,羽化也极不整齐,长日条件(LD 16∶8h)、中间日照条件(LD 14∶10h)和短日条件(LD 12∶12h)的若虫发育历期(mean±SD)分别为(206.2±44.0)d、(236.6±93.3)d和(230.3±47.4)d,若虫从开始羽化到供试个体全部完成羽化所需时间分别为216、301和156d,经历短日条件的若虫转移至长日条件后能够促进其快速发育,羽化也很整齐,反方向转移则会抑制若虫发育,且羽化也不整齐。30℃温度条件下,恒定长日条件下的若虫发育明显快于短日条件,变化光周期对若虫发育的调控与25℃相类似。变化光周期对若虫发育的影响与光周期的变化方向及低龄若虫感受的光周期类型有关。丽斗蟋若虫复杂的光周期反应模式的生态意义在于调节其生活史与季节同步。

The effects of constant and changing photoperiod on nymphal development are investigated to understand the seasonal life-cycle strategy of a nymph-overwintering cricket, Velarifictonus ornatus, in Zhuzhou, Hunan. Nymphal development was slow under constant photoperiods at 25℃. The shortest mean duration of nymphal development was （206.2 ± 44.0） （mean ± SD） days at LD 16：8 h, followed by （230.3±47.4） days at LD 12：12 h and （236.5±93.3） days at LD 14：10 h. No significant difference was observed in the nymphal durations among different constant photoperiods at 25℃. Nymphal development was further prolonged when nymphs were exposed to LD 16：8 h during the first 60 days and then transferred to LD 14：10 h or LD 12：12 h at 25℃. Similar results were obtained when nymphs were transferred from LD 14：10 h to LD 12：12 h at 60 days after hatching at 25℃. However, in the reverse transfer, i.e. from short days to long days, the durations of nymphal development was dramatically shortened. When nymphs were transferred from LD 12：12 h to LD 16：8 h at 10, 30, 60 or 90 days after hatching, the mean nymphal durations were （135.9 ± 88.5 ）, （ 80.0 ± 5.9 ）, （ 110.4 ± 10.4） and （ 142.9 ± 10.8 ） days respectively. When photoperiod was shifted from LD 12：12 h to LD 14：10 h at 60 days after hatching, the nymphal duration was （ 120.9 ± 7.7 ） days. Nymphs exposed to those photoperiodic shift developed faster than those kept at constant photoperiods. Although adults emerged more rapidly under long days than those reared under short days at 30℃, changing photoperiods showed similar results on nymphal development as those at 25℃. These results suggested that seasonal changing day-length controls nymphal development of V. ornatus to synchronize their life-cycle with the season.