School of Forestry, Northeast Forestry University, Harbin 150040, PR China; Key Laboratory of Sustainable Forest Ecosystem Management, Ministry of Education, Northeast Forestry University, Harbin 150040, PR China.
Forest Botanical Garden of Heilongjiang Province, Harbin 150040, PR China.
Sci Total Environ. 2023 Aug 20;887:164106. doi: 10.1016/j.scitotenv.2023.164106. Epub 2023 May 11.
The toxicity of heavy metals on various trophic levels along the food chain has been extensively investigated, but no studies have focused on parasitic natural enemy insects. Herein, we constructed a food chain consisting of soil-Fraxinus mandshurica seedlings-Hyphantria cunea pupae-Chouioia cunea to analyze the effects of Cd exposure through food chain on the fitness of parasitic natural enemy insects and its corresponding mechanism. The results showed that the transfer of Cd between F. mandshurica leaves and H. cunea pupae and between H. cunea pupae and C. cunea was a bio-minimization effect. After parasitizing Cd-accumulated pupa, the number of offspring larvae, and the number, individual size (body weight, body length, abdomen length) and life span of offspring adults decreased significantly, while the duration of embryo development extended significantly. The contents of malondialdehyde and HO in Cd-exposed offspring wasps increased significantly, accompanied by a significantly decrease in antioxidant capacity. The cellular immunity parameters significantly decreased in Cd-accumulated pupae, including the number of hemocytes, melanization activity and the expression level of cellular immunity genes (e.g. Hemolin-1 and PPO1). The humoral immunity disorder was found in the Cd-accumulated pupae, as evidenced by that the expression level of immune recognition gene (PGRP-SA), signal transduction genes (IMD, Dorsal, and Tube), as well as all antimicrobial peptide genes (e.g. Lysozym and Attacin) decreased significantly. Cd exposure decreased the content of glucose, trehalose, amino acid, and free fatty acid in H. cunea pupae. The expression of Hk2 in glycolysis pathway and the expression of Idh2, Idh3, Cs, and OGDH in TCA cycle pathway were significantly down-regulated in Cd-accumulated pupae. Taken together, exposure to Cd through the food chain causes oxidative damage on the offspring wasps and disrupts energy metabolism of the host insect, ultimately reducing the parasitic fitness of C. cunea to H. cunea pupae.
重金属对食物链各营养级的毒性已得到广泛研究，但尚无研究关注寄生性天敌昆虫。本研究构建了包含土壤-水曲柳(Fraxinus mandshurica)幼苗-美国白蛾(Hyphantria cunea)蛹-周氏啮小蜂(Chouioia cunea)的食物链，分析了通过食物链传递 Cd 对寄生性天敌昆虫适应性及其相应机制的影响。结果表明，Cd 在水曲柳叶片与美国白蛾蛹、美国白蛾蛹与周氏啮小蜂之间的转移存在生物最小化效应。寄生在 Cd 积累蛹上后，子代幼虫数量、雌雄成虫个体大小(体重、体长、腹长)及寿命均显著降低，而胚胎发育持续时间显著延长。Cd 暴露子代蜂体内丙二醛和 HO 含量显著增加，抗氧化能力显著降低。Cd 积累蛹的细胞免疫参数显著降低，包括血细胞数量、黑化活性和细胞免疫基因(如 Hemolin-1 和 PPO1)的表达水平。Cd 积累蛹还出现了体液免疫紊乱，表现为免疫识别基因(PGRP-SA)、信号转导基因(IMD、Dorsal 和 Tube)和所有抗菌肽基因(如 Lysozym 和 Attacin)的表达水平显著降低。Cd 暴露降低了美国白蛾蛹体内葡萄糖、海藻糖、氨基酸和游离脂肪酸的含量。Cd 积累蛹中糖酵解途径的 Hk2 和三羧酸循环途径的 Idh2、Idh3、Cs 和 OGDH 的表达均显著下调。总之，通过食物链暴露于 Cd 会对子代蜂造成氧化损伤，并破坏宿主昆虫的能量代谢，最终降低周氏啮小蜂对美国白蛾蛹的寄生适应性。
Zotero 插件