光周期对大草蛉(Chrysopa pallens)滞育及发育的影响

Effect of photoperiod on induction of prepupal diapause and larval development in Chrysopa pallens(Rambur)(Neuroptera:Chrysopidae)

在22℃条件下,研究大草蛉对光周期的敏感性,结果表明:大草蛉属短日照滞育型,在短光照条件下饲养获得的预蛹进入滞育状态,诱导预蛹滞育的临界光周期为10.5L-13.5D到11L-13D。2龄幼虫期是诱导预蛹滞育的敏感虫期,只有当2龄幼虫期处于短光照条件下时才能进入滞育状态。1龄和3龄幼虫期也在滞育诱导条件下进行滞育诱导,能够提高滞育率。光周期对大草蛉幼虫历期及预蛹重的影响研究结果表明:光周期对幼虫历期有一定的影响,特别对2龄幼虫期的影响比较明显。幼虫期的光周期条件影响预蛹的重量,滞育预蛹的重量显著高于非滞育预蛹。

The effects of photoperiod on the prepupal diapause and larval development were examined in the green lacewing, Chrysopa pallens （Rambur） at 22℃. Photoperiodic responses of Ch. pallens showed short-day type, and the critical photoperiod for diapause induction was estimated to be between 10.5L-13.5D and llL-13D. The second instar larvae was the most sensitive stage for prepupal diapause induction, the prepupae could go into diapause only when the second instar larvae was subjected to the diapause-inducing short-day conditions. Diapause incidence became higher when the induction throughout larval instars 1 - 3 than only the larval instar 2. This results suggested that the first and third instar larvae had a certain degree of sensitivity to diapause-inducing photoperiods. Effects of the different photoperiods on the developmental periods of larvae stage and prepual weight of Ch. pallens were also investigated. The results showed that the second instar larvae stage was extended when they were kept under the short-day photoperiods, and the developmental duration of the second instar larvae grown under the photoperiods of 9L-15D and 11L-13D were significantly longer than that of 12L-12D and 15L-9D. The weight of diapauseing prepupae grown under the diapause-inducing short-day conditions was significantly higher than that of the non-diapause prepupae grown under the long-day or short-day conditions.