Cadmium (Cd) is a heavy metal that is of great concern in the agroecosystem, because of its toxicity to plants and herbivores. Previous research has suggested that populations of herbivorous insects can be affected by Cd, via disrupting tri-trophic interactions comprising plants, herbivores, and predators. However, there is less understanding of the direct effects of dietary Cd on the life history traits and the detoxification or antioxidant enzyme systems of insects. Here we show that the life history traits of the herbivorous oriental armyworm, Mythimna separata (Walker), can be impacted by Cd. The body mass of larvae was decreased under an artificial diet containing a low (0.15 mg kg-1) Cd concentration, but was increased by intermediate (0.30 mg kg-1) and high (0.60 mg kg-1) concentrations of Cd. In contrast, pupal weight declined under intermediate and high concentrations of Cd compared to either low Cd concentration or the control. When Cd concentrations increased, larvae survival rate and fecundity decreased and the pupation rate and pupal deformity rate increased. Low and intermediate concentrations of Cd extended the length of the larval stage while high concentrations of Cd shortened the larval period. Dietary Cd inhibited the activity of antioxidant enzyme polyphenol oxidase (PPO), but increased acetylcholinesterase (AChE) activity and the activities of detoxifying enzymes carboxylesterase (CarE) and glutathione S-transferase (GST) of third-instar larvae. Overall, our results indicate that for Cd concentration there is a physiological trade-off between its adverse effects on life history traits and elevated detoxification, acetylcholinesterase sensitivity and antioxidation of M. separata, thus representing a potential adaptation strategy.

中文翻译：

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饮食介导的镉对东方粘虫Mythimna separata健身相关性状，排毒和抗氧化酶的影响

镉（Cd）是一种重金属，在农业生态系统中受到极大关注，因为它对植物和草食动物具有毒性。先前的研究表明，食草昆虫种群可通过破坏包括植物，草食动物和捕食者的三营养相互作用而受到镉的影响。但是，人们对饮食中镉对昆虫的生活史特征和排毒或抗氧化酶系统的直接影响了解较少。在这里，我们显示了食草东方夜蛾Mythimna separata（Walker）的生活史特征可能会受到Cd的影响。在低（0.15 mg kg-1）Cd浓度的人工饮食下，幼虫的体重降低了，但是在中等（0.30 mg kg-1）和高（0.60 mg kg-1）镉浓度下，幼虫的体重增加了。相反，与低Cd浓度或对照组相比，在中等和高Cd浓度下体重下降。当镉浓度增加时，幼虫成活率和繁殖力下降，化up率和p畸形率增加。中低浓度的镉会延长幼虫期的长度，而高浓度的镉会缩短幼虫期。饲料中的镉抑制了三龄幼虫的抗氧化酶多酚氧化酶（PPO）的活性，但增加了乙酰胆碱酯酶（AChE）的活性以及解毒酶羧酸酯酶（CarE）和谷胱甘肽S-转移酶（GST）的活性。总体而言，我们的结果表明，对于Cd浓度，其对生活史特征的不利影响与排毒量的增加之间存在生理上的权衡，