无患子皂苷对甜菜夜蛾的影响及其化学成分分析

为明确无患子皂苷对甜菜夜蛾的控制作用，本试验分别用添加无患子皂苷(0.25、0.5、1、2、4、8、16 mg/g)的混毒饲料喂养甜菜夜蛾2龄幼虫，测定甜菜夜蛾幼虫存活率、幼虫发育历期、蛹重、化蛹率、卵孵化率、性比等指标。采用液相色谱-质谱联用仪(HPLC-MS)分析无患子皂苷中的主要化学成分。结果表明，喂饲后72 h,取食4 mg/g混皂苷饲料的甜菜夜蛾幼虫开始死亡，其幼虫存活率随皂苷浓度的升高而降低；相比空白对照组，取食4 mg/g混皂苷饲料的幼虫，其幼虫期延长8.55 d(P<0.05),蛹重降低了41.13%(P<0.05),化蛹率下降46.43%(P<0.05)。取食0.5 mg/g以及2 mg/g混皂苷饲料的幼虫其卵孵化率分别比空白对照降低9.61%、16.12%;取食混有皂苷的饲料会扰乱甜菜夜蛾的性比，其中混入2 mg/g皂苷的处理对其性比影响最大，雌性比为25.00%。从无患子皂苷中鉴定出10种皂苷类化合物，共鉴别出6种常春藤型三萜皂苷，3种齐墩果酸型三萜皂苷，1种大戟烷型三萜皂苷。

Effects of Sapindus saponin on the growth, development and reproduction of Spodoptera exigua and analysis of its chemical composition

In order to clarify the control effect of Sapindus saponin on Spodoptera exigua, the 2nd instar larvae of S. exigua were fed with the feed mixed with seven different concentrations (0.25, 0.5, 1, 2, 4, 8 and 16 mg/g) of Sapindus saponin. The larval survival rate, larval developmental duration, pupal weight, pupation rate, egg hatching rate and sex ratio of S. exigua were measured. The main chemical components of Sapindus saponin were analyzed by liquid chromatography-mass spectrometry (HPLC-MS). The results showed that the death of larvae began to appear at 72 h after feeding with 4 mg/g saponin and the survival rate of larvae decreased with increasing concentration of saponin. The larval stage prolonged by 8.55 d; the pupal weight was significantly decreased by 41.13%, and the pupation rate was significantly decreased by 46.43 compared with the control group. The egg hatching rate decreased by 9.61% and 16.12%, respectively, compared with the control group when fed with 0.5 mg/g or 2 mg/g saponin. The moth sex ratio was biased by feeding saponin, and 2 mg/g saponin had the greatest impact on the sex ratio, with a female to male ratio of 25.00%. Ten saponins were identified from Sapindus, including six ivy-type triterpenoid saponins, three oleanolic acid-type triterpene saponins, and one euphorbia-type triterpene saponin.