Jen-Teh Junior College of Medicine, Nursing and Management, Miaoli County 35665, Taiwan.
J Econ Entomol. 2012 Oct;105(5):1591-6. doi: 10.1603/ec12075.
Although fire ants frequently have negative impacts on agricultural systems and public health, they have additional beneficial insecticidal effects. To evaluate the potential effect of fire ant venoms on agricultural pests, the compositions of the venoms and their insecticidal activities against Plutella xylostella (L.) larvae were evaluated under laboratory conditions. The alkaloids found in Solenopsis geminata (F.) venom are primarily saturated C11, which occur in both cis and trans forms, whereas the venom of S. invicta Buren contains six principal alkaloids (from trans C1, to C17). Moreover, the proportions of unsaturated alkaloids in the venom of polygynous S. invicta were significantly higher than the corresponding proportions in the monogynous S. invicta, as shown by our previous studies. Fire ant venoms were topically applied to the dorsal thoracic region of fourth-instar larvae of P. xylostella. The results of the experiment showed that the larval symptoms induced by fire ant venom include contractile, flaccid paralysis, black coloration and death. P. xylostella larvae were most susceptible to S. geminata venom. The order of the susceptibilities of the larvae to the venoms was as follows: S. geminata > S. invicta (monogyne form) > S. invicta (polygyne form), as measured by the corresponding LT50 values at 24 h.
尽管火蚁经常对农业系统和公共卫生产生负面影响，但它们还有其他有益的杀虫作用。为了评估火蚁毒液对农业害虫的潜在影响，在实验室条件下评估了毒液的成分及其对小菜蛾幼虫的杀虫活性。在 S. geminata (F.) 毒液中发现的生物碱主要是饱和的 C11，它们以顺式和反式两种形式存在，而 S. invicta Buren 的毒液含有六种主要生物碱（从反式 C1 到 C17）。此外，多态 S. invicta 毒液中不饱和生物碱的比例明显高于单态 S. invicta 的相应比例，这是我们之前的研究结果。火蚁毒液被局部应用于小菜蛾四龄幼虫的背部胸部区域。实验结果表明，火蚁毒液引起的幼虫症状包括收缩性、弛缓性麻痹、黑化和死亡。小菜蛾幼虫对 S. geminata 毒液最敏感。幼虫对毒液的敏感性顺序如下：S. geminata > S. invicta（单态形式）> S. invicta（多态形式），这是通过 24 小时时相应的 LT50 值来衡量的。
