前足跗节及触角在小菜蛾雌蛾对芥子油苷刺激产卵反应中的作用

The role of foreleg tarsus and antennae in the oviposition preference stimulated by glucosinolates in Plutella xylostella

[目的]小菜蛾是十字花科植物专食性昆虫,以芥子油苷为重要味觉信号来识别寄主植物进行产卵。本研究旨在证实芥子油苷对小菜蛾雌蛾产卵的刺激作用,并进一步明确前足跗节和触角在芥子油苷感受中的作用,为深入研究芥子油苷的感受机制奠定基础。[方法]利用小罩笼法并以封口膜为产卵介质,通过测定小菜蛾在芥子油苷(粗提液)处理和对照封口膜间向芥子油苷的产卵偏好性(选择指数),确定芥子油苷对小菜蛾雌蛾产卵的刺激作用;分别以封口膜和植物叶片为产卵介质,通过比较小菜蛾3个处理(酸蚀前足跗节、切除触角、切除触角+酸蚀前足跗节)的产卵选择指数与对照雌蛾间的差异,确定前足跗节和触角在小菜蛾感受芥子油苷中的作用。[结果]芥子油苷(粗提液)对小菜蛾产卵具有显著刺激作用,且在测试浓度范围(0.01%~5%)内随浓度增加而增强。酸蚀前足跗节和去除触角均显著降低雌蛾对芥子油苷(粗提液)的产卵偏好性,但处理间无显著差异;当触角和前足跗节都去除后,产卵偏好性显著降低,以植物叶片为产卵介质时选择指数由0.94降低到0.42,以封口膜为产卵介质时由0.59降低到近乎为零。[结论]芥子油苷显著影响小菜蛾雌蛾的产卵偏好性,前足跗节和触角均发挥重要作用。

[Objectives]The diamondback moth,Plutella xylostella,is a Crucifer specialist,using glucosinolate as an important taste signal to identify the host plants for egg laying.The purpose of this study was to confirm the stimulating effect of glucosinolate on the oviposition of female P.xylostella,and further to clarify the role of the foreleg tarsus and antennae in glucosinolate perception,thus to lay a foundation for in-depth study on the perception mechanism of glucosinolate.[Methods]To determine the stimulating effect of glucosinolate on the oviposition of female P.xylostella,the oviposition preference(indicated by preference index)between glucosinolate(crude extract)treated and control parafilms was calculated using the small cage method with parafilm as oviposition medium.To determine roles of foreleg tarsus and antennae in the glucosinolate perception,the oviposition preference indices of treated female moths(with acid ablation of foreleg tarsus,removal of antennae,or both acid ablation of foreleg tarsus and removal of antennae)were compared with those of control female moth,using the same small cage method with parafilm and plant leaves as oviposition medium,respectively.[Results]Glucosinolate(crude extract)showed significant oviposition-stimulating effect on female P.xylostella,in a dose dependent pattern within the range of test concentration(0.01%-5%).Acid ablation of foreleg tarsus or removal of antennae significantly reduced the oviposition preference for glucosinolate,but there was no significant difference between the two treatments(antenna removal and tarsus removal).When both antennae and foreleg tarsus were removed,the oviposition preference was further significantly reduced,with the preference index decreasing from 0.94 in control moths to 0.42 in the tissue removed moths using plant leaves as oviposition medium,and from 0.59 to about zero using parafilm as oviposition medium.[Conclusions]Glucosinolates significantly affected the oviposition preference of female P.xylostella,in which foreleg tarsus and antennae played similar important roles.