Insecticide induced-hormesis, a bi-phasic phenomenon characterized by low dose stimulation and high dose inhibition following exposure to insecticide, is crucial to insect pest resurgence. In this study, the effects of low or sublethal concentrations of thiamethoxam on biological traits and genes expression were investigated for Aphis gossypii Glover following 72 h exposures. Leaf-Dip bioassay results showed that thiamethoxam was very toxic against adult A. gossypii with an LC50 of 1.175 mg L-1. The low lethal (LC15) and sublethal (LC5) concentrations of thiamethoxam significantly reduced longevity and fecundity of the directly exposed aphids. However, stimulatory effects on pre-adult stage, longevity, and fertility were observed in the progeny generation (F1) of A. gossypii, when parental aphids (F0) were exposed to LC15 of thiamethoxam. Subsequently, biological traits such as intrinsic rate of increase (r), finite rate of increase (λ), and net reproductive rate (R0) increased significantly to F1 individuals due to LC15 treatment. No significant responses were observed for LC5 of thiamethoxam. The LC15 of thiamethoxam significantly increased the expression level of vitellogenin and ecdysone receptors genes in progeny generation, while no effects were observed for treatment with LC5. Additionally, the expression levels of P450 genes including CYP6CY14, CYP6CZ1, CYP6DC1, CYP6CY9, and CYP6DD1 were up-regulated in the exposed aphids. Taken together, our results show the hormetic effects of thiamethoxam on F1 individuals, which might be due to the intermittent changes in expression of genes involved in fertility, growth and insecticide detoxification in A. gossypii.

中文翻译：

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噻虫嗪在棉蚜中诱导跨代兴奋效应和基因表达的改变

杀虫剂诱导刺激作用是一种以暴露于杀虫剂后的低剂量刺激和高剂量抑制为特征的双相现象，对害虫死灰复燃至关重要。在这项研究中，低或亚致死浓度的噻虫嗪对接触 72 小时后的棉蚜 Glover 的生物学特性和基因表达的影响进行了研究。Leaf-Dip 生物测定结果表明，噻虫嗪对成年棉曲霉具有很强的毒性，LC50 为 1.175 mg L-1。噻虫嗪的低致死 (LC15) 和亚致死 (LC5) 浓度显着降低了直接暴露的蚜虫的寿命和繁殖力。然而，当亲本蚜虫 (F0) 暴露于噻虫嗪的 LC15 时，在棉蚜的后代 (F1) 中观察到对成年前阶段、寿命和生育力的刺激作用。随后，由于LC15处理，F1个体的内在增长率（r）、有限增长率（λ）和净繁殖率（R0）等生物学特性显着增加。未观察到噻虫嗪的 LC5 的显着反应。噻虫嗪的 LC15 显着增加了后代中卵黄蛋白原和蜕皮激素受体基因的表达水平，而用 LC5 治疗没有观察到影响。此外，包括 CYP6CY14、CYP6CZ1、CYP6DC1、CYP6CY9 和 CYP6DD1 在内的 P450 基因的表达水平在暴露的蚜虫中上调。综上所述，我们的结果显示了噻虫嗪对 F1 个体的兴奋作用，这可能是由于与 A. gossypii 生育力、生长和杀虫剂解毒有关的基因表达的间歇性变化所致。由于 LC15 处理，F1 个体的内在增长率 (r)、有限增长率 (λ) 和净繁殖率 (R0) 等生物学特性显着增加。未观察到噻虫嗪的 LC5 的显着反应。噻虫嗪的 LC15 显着增加了后代中卵黄蛋白原和蜕皮激素受体基因的表达水平，而用 LC5 治疗没有观察到影响。此外，包括 CYP6CY14、CYP6CZ1、CYP6DC1、CYP6CY9 和 CYP6DD1 在内的 P450 基因的表达水平在暴露的蚜虫中上调。综上所述，我们的结果显示了噻虫嗪对 F1 个体的兴奋作用，这可能是由于与 A. gossypii 生育力、生长和杀虫剂解毒有关的基因表达的间歇性变化所致。由于 LC15 处理，F1 个体的内在增长率 (r)、有限增长率 (λ) 和净繁殖率 (R0) 等生物学特性显着增加。未观察到噻虫嗪的 LC5 的显着反应。噻虫嗪的 LC15 显着增加了后代中卵黄蛋白原和蜕皮激素受体基因的表达水平，而用 LC5 治疗没有观察到影响。此外，包括 CYP6CY14、CYP6CZ1、CYP6DC1、CYP6CY9 和 CYP6DD1 在内的 P450 基因的表达水平在暴露的蚜虫中上调。综上所述，我们的结果显示了噻虫嗪对 F1 个体的兴奋作用，这可能是由于与 A. gossypii 生育力、生长和杀虫剂解毒有关的基因表达的间歇性变化所致。