Universidade Estadual Paulista (UNESP), Instituto de Biociências, Rio Claro. Departamento de Biologia Geral e Aplicada, Programa de pós graduação em Ciências Biológicas: Biologia Celular, Molecular e Microbiologia, Brazil.
Center of Agrarian Sciences, Federal University of São Carlos (UFSCar), Anhanguera Road Km 174, Araras, SP, Brazil.
Chemosphere. 2024 Sep;363:142853. doi: 10.1016/j.chemosphere.2024.142853. Epub 2024 Jul 15.
Bees play a crucial role as pollinating insects in both natural and cultivated areas. However, the use of pesticides, such as thiamethoxam, has been identified as a contributing factor compromising bee health. The current risk assessment primarily relies on the model species Apis mellifera, raising concerns about the applicability of these assessments to other bee groups, including stingless bees. In this study, we investigated the acute toxicity of thiamethoxam on the stingless bee Frieseomelitta varia by determining the average lethal concentration (LC) and mean lethal time (LT). Additionally, we evaluated the enzymatic profile of Acetylcholinesterase (AChE), Carboxylesterase-3 (CaE-3), and Glutathione S-Transferase (GST), in the heads and abdomens of F. varia after exposure to thiamethoxam (LC). The LC of thiamethoxam was determined to be 0.68 ng ai/μL, and the LT values were 37 days for the control group, 25 days at LC, and 27 days at LC. The thiamethoxam significantly decreased the survival time of F. varia. Furthermore, the enzymatic profile exhibited differences in CaE3 activity within one day in the heads and ten days in the abdomen. GST activity showed differences in the abdomen after one and five days of thiamethoxam exposure. These findings suggests that the abdomen is more affected than the head after oral exposure to thiamethoxam. Our study provides evidence of the toxicity of thiamethoxam at both the cellular and organismal levels, reinforcing the need to include non-Apis species in pollinator risk assessments. and provide solid arguments for bee protection.
蜜蜂在自然和栽培区域中作为传粉昆虫起着至关重要的作用。然而，杀虫剂的使用，如噻虫嗪，已被确定为危害蜜蜂健康的一个因素。目前的风险评估主要依赖于模式物种西方蜜蜂，这引起了人们对这些评估对包括无刺蜜蜂在内的其他蜜蜂群体适用性的关注。在这项研究中，我们通过确定蜜蜂急性毒性的平均致死浓度 (LC) 和平均致死时间 (LT)，研究了噻虫嗪对无刺蜜蜂 Frieseomelitta varia 的急性毒性。此外，我们还评估了暴露于噻虫嗪后（LC），F. varia 头部和腹部中的乙酰胆碱酯酶 (AChE)、羧酸酯酶-3 (CaE-3) 和谷胱甘肽 S-转移酶 (GST) 的酶谱。噻虫嗪的 LC 为 0.68ng ai/μL，LT 值为对照组 37 天，LC 为 25 天，LC 为 27 天。噻虫嗪显著降低了 F. varia 的存活时间。此外，酶谱在头部 1 天和腹部 10 天内显示 CaE3 活性的差异。在腹部，GST 活性在接触噻虫嗪 1 天和 5 天后显示出差异。这些发现表明，与头部相比，F. varia 在口服接触噻虫嗪后腹部受到的影响更大。我们的研究提供了噻虫嗪在细胞和机体水平上的毒性证据，这加强了在传粉者风险评估中纳入非西方蜜蜂物种的必要性，并为蜜蜂保护提供了有力的论据。
