PDF(Pubmed)
Abstract：
Silkworm Bombyx mori (L.) (Lepidoptera: Bombycidae) is a critical insect for silk producers, but the inappropriate application of insecticides negatively affects the physiology and behavior of silkworms. This study found that the effects of neonicotinoid insecticides applied using two spraying methods on the growth and development of silkworms were different: the median lethal concentration (LC50) values of two pesticides applied using the leaf-dipping method were 0.33 and 0.83 mg L-1 and those of two pesticides applied using the quantitative spraying method were 0.91 and 1.23 mg kg-1. The concentration of pesticides on the mulberry leaves did not decrease after their application using the quantitative spraying method, and a uniform spraying density was observed after the mulberry leaves were air-dried (no liquid) under realistic conditions. We then treated silkworms with the quantitative spraying method and leaf-dipping method. The treatment of silkworm larvae with imidacloprid and thiamethoxam at sublethal concentrations significantly prolonged the development time and significantly decreased the weight and pupation rate, as well as economic indicators of enamel layers and sputum production. Thiamethoxam treatment significantly increased the activities of carboxylesterase (CarE) and glutathione-S-transferase (GST). The activity of CarE and GST increased, decreased, and then increased, and the highest activity was detected on the 10th and 12th days. Thiamethoxam exposure significantly elevated the transcription levels of CarE-11, GSTe3 and GSTz2 and induced DNA damage in hemocytes. This study confirmed that the quantitative spray method is more stable than the leaf-dipping method. Moreover, imidacloprid and thiamethoxam treatment affected the economy and indexes of silkworms and induced changes in detoxification enzymes and DNA damage in silkworms. These results provide a basis for understanding the mechanism of the sublethal effects of insecticides on silkworms.
摘要：
家蚕(L.）（鳞翅目：Bombycidae）是丝绸生产者的关键昆虫，但是杀虫剂的不当使用会对蚕的生理和行为产生负面影响。本研究发现，采用两种喷施方式施用的新烟碱类杀虫剂对家蚕生长发育的影响是不同的：采用浸叶法施用的两种杀虫剂的中位致死浓度（LC50）值分别为0.33和0.83mgL-1，采用定量喷施方式施用的两种杀虫剂的中位致死浓度（LC50）值分别为0.91和1.23mgkg-1。使用定量喷施方法施用后,桑叶上的农药浓度没有下降,在实际条件下将桑叶风干（无液体）后，观察到均匀的喷雾密度。然后，我们用定量喷雾法和浸叶法处理蚕。用亚致死浓度的吡虫啉和噻虫嗪处理家蚕幼虫可显著延长发育时间,显著降低体重和化蛹率,以及搪瓷层和痰液生产的经济指标。噻虫嗪处理显着增加了羧酸酯酶（CarE）和谷胱甘肽-S-转移酶（GST）的活性。CarE和GST的活性增加，减少,然后增加，在第10天和第12天检测到最高的活动。噻虫嗪暴露显着提高了CarE-11，GSTe3和GSTz2的转录水平，并诱导了血细胞中的DNA损伤。这项研究证实，定量喷雾法比浸叶法更稳定。此外，吡虫啉和噻虫嗪处理影响家蚕的经济和指标，并引起家蚕解毒酶和DNA损伤的变化。这些结果为了解杀虫剂对家蚕的亚致死作用机理提供了依据。
