抗生素和肠道细菌对小菜蛾适合度的影响

【目的】小菜蛾是危害十字花科蔬菜的世界性重要害虫。通过分析抗生素对小菜蛾的毒性效应,了解肠道细菌对小菜蛾适合度的影响,有助于更好地阐明小菜蛾肠道细菌的功能。【方法】利用抗生素处理含有高丰度肠道细菌的萝卜苗饲养品系(FZss)小菜蛾幼虫,同时利用抗生素处理饲料饲养的无肠道细菌(SLss)小菜蛾幼虫,分析抗生素及肠道细菌对小菜蛾适合度的影响。【结果】抗生素处理FZss品系小菜蛾导致了小菜蛾发育历期延长,虫重、蛹重、化蛹率、产卵量和成虫寿命降低。利用抗生素处理无肠道菌的SLss品系小菜蛾幼虫,小菜蛾化蛹率和单雌产卵量均显著降低,而对发育历期、虫重和蛹重则无影响。【结论】综合两个研究的结果发现抗生素处理后宿主适合度的降低一方面是由于抗生素的毒性效应导致,另一方面是由于小菜蛾肠道细菌的缺失引起。抗生素的毒性效应主要表现为对化蛹率和单雌产卵量的影响,而肠道细菌则对小菜蛾的发育历期、虫重、蛹重以及成虫寿命具有重要的促进作用。

Effect of antibiotics and gut bacteria on fitness of diamondback moth Plutella xylostella (L.)

Objective] Diamondback moth (DBM) Plutella xylostella (L.) is the most important pest of cruciferous crops worldwide. The purpose of this study was to find the effect of gut bacteria and antibiotics on the fitness of DBM. Methods] The radish DBM strain and the germ-free artificial diet DBM strain were reared under antibiotic, and then the effect of gut bacteria and antibiotics on the fitness of DBM was evaluated. Results] The antibiotic-treatment on the radish DBM strain has reduced hosts'' fitness, reflected as retarded development, reduced weights, declined pupation rates, descended fecundity and shorted adult life-span. The antibiotic-treatment on the germ-free artificial diet DBM strain decreased pupation rate and fecundity. Conclusion] Negative effects on the host fitness after antibiotic treatment was partly caused by the toxic effect of antibiotic and partly by the deficiency of gut bacteria. The gut bacteria may play a promote role in the fitness of DBM.