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

研究了雌蜂对寄主小菜蛾幼虫侵染十字花科植物(Brassica Rapa)的飞行反应。我们发现，寄主侵染的十字花科植物发出的挥发性SOS信号(例如苯基氰化物)可以被寄生蜂利用作为觅食线索。然后，我们研究了几种杀虫剂(氯菊酯和其他七种杀虫剂)对威斯特兰幼虫觅食行为和生存的影响。结果表明，氯氰菊酯、乙氰菊酯、马拉硫磷、二氮磷、灭多威、丙二醛对寄生蜂的觅食行为(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，而氯氰菊酯和苯甲酸阿维菌素的抑制作用相对较弱。有趣的是，在氯硫醚处理的植物上取食后，寄生蜂的死亡率显著高于在其他杀虫剂处理的植物上取食后的死亡率。我们的结果表明，随着对威斯汀觅食行为的抑制作用的减弱，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.