Inhibitory effects of synthetic insecticides on the foraging behavior of natural enemies via volatile infochemicals (SOS signals) emitted from plants infested with pest insects and mites

摘要研究了十字花科植物（Brassica rapa）被其寄主小菜蛾（Plutella xylostella）幼虫侵染时雌拟寄生蜂（Cotesia vestalis）的飞行反应。我们发现，寄主侵染十字花科植物释放的挥发性SOS信号（如苯基氰化物）可以被寄生蜂利用作为觅食线索。研究了氯菊酯等7种杀虫剂对夜蛾觅食行为和存活率的影响。结果表明，氯菊酯、乙托苯丙酯、马拉硫磷、二嗪农、灭多威、丙氰威对寄生蜂的觅食行为（即对寄主植物的飞行反应、对寄主植物的寻找）有较强的抑制作用，而噻虫胺和甲维菌素苯甲酸酯的抑制作用较弱。有趣的是，寄生蜂在虫胺处理过的植物上觅食后的死亡率显著高于在其他处理过的植物上觅食后的死亡率。我们的研究结果表明，随着对vestalis觅食行为的抑制作用降低，随后的死亡率增加。

We investigated the flight response of female parasitoids (Cotesia vestalis) to the cruciferous plants (Brassica rapa) infested with larvae of their host, the diamond back moth (Plutella xylostella), an important pest of cruciferous plants. We found that volatile SOS signals (e.g. benzyl cyanide) emitted from host-infested cruciferous plants can be exploited by the parasitoids as a foraging cue. We then investigated the effects of some insecticides (permethrin and other seven insecticides) on the foraging behavior and survival of C.vestalis. We found that permethrin, etofenprox, malathion, diazinon, methomyl, alanycarb had relatively strong inhibitory effects on the foraging behavior (i.e. flight response to host-infested plants, host-searching on the host-infested plants) of the parasitoids, while clothianidin and emamectin benzoate had relatively weak inhibitory effets. Interestingly, the mortality of parasitoid wasps after foraging on the clothianidin-treated plants was significantly higher than that after foraging on other insecticide-treated plants. Our results suggest that subsequent mortality increases with decreased inhibitory effect on the foraging behavior of C.vestalis.