Conceição de Assis Josimere, Eduardo da Costa Domingues Caio, Tadei Rafaela, Inês da Silva Cláudia, Soares Lima Hellen Maria, Decio Pâmela, Silva-Zacarin Elaine C M
Federal University of São Carlos, UFSCar, Postgraduate Program in Biotechnology and Environmental Monitoring, Sorocaba, São Paulo State, Brazil.
University of Maribor, Faculty of Agriculture and Life Sciences, Pivola, Slovenia.
Environ Pollut. 2022 Jul 1;304:119140. doi: 10.1016/j.envpol.2022.119140. Epub 2022 Mar 14.
Solitary bees present greater species diversity than social bees. However, they are less studied than managed bees, mainly regarding the harmful effects of pesticides present in agroecosystems commonly visited by them. This study aimed to evaluate the effect of residual doses of imidacloprid and pyraclostrobin, alone and in combination, on the fat body (a multifunctional organ) of the neotropical solitary bee Tetrapedia diversipes by means of morphological and histochemical evaluation of oenocytes and trophocytes. Males and females of newly-emerged adults were submitted to bioassays of acute topical exposure. Experimental groups were essayed: control (CTR), solvent control (ACT), imidacloprid (IMI, 0.0028 ng/μL), pyraclostrobin (PYR, 2.7 ng/μL) and imidacloprid + pyraclostrobin (I + P). The data demonstrated that the residual doses applied in T. diversipes adults are sublethal at 96 h. Both oenocytes and trophocytes cells responded to topical exposure to the pesticides, showing morphological changes. In the IMI group, the bee oenocytes showed the greatest proportion of vacuolization and altered nuclei. The pyraclostrobin exposure increased the intensity of PAS-positive labeling (glycogen) in trophocytes. This increase was also observed in the I + P group. Changes in energy reserve (glycogen) of trophocytes indicate a possible mobilization impairment of this neutral polysaccharide to the hemolymph, which can compromise the fitness of exposed individuals. Also, changes in oenocytes can compromise the detoxification function performed by the fat body. This is the first study to show sublethal effects in neotropical solitary bees and highlight the importance of studies with native bees.
独居蜂的物种多样性比群居蜂更高。然而，与养殖蜜蜂相比，它们受到的研究较少，主要是关于它们常去的农业生态系统中农药的有害影响。本研究旨在通过对oenocytes和trophocytes进行形态学和组织化学评估，来评价吡虫啉和吡唑醚菌酯单独及联合使用的残留剂量对新热带独居蜂Tetrapedia diversipes脂肪体（一种多功能器官）的影响。新羽化的成年雌雄蜂接受急性局部暴露生物测定。设置了实验组：对照组（CTR）、溶剂对照组（ACT）、吡虫啉组（IMI，0.0028 ng/μL）、吡唑醚菌酯组（PYR，2.7 ng/μL）和吡虫啉 + 吡唑醚菌酯组（I + P）。数据表明，施加于T. diversipes成虫的残留剂量在96小时时为亚致死剂量。Oenocytes和trophocytes细胞对局部暴露于农药均有反应，表现出形态变化。在IMI组中，蜜蜂的oenocytes显示出最大比例的空泡化和细胞核改变。吡唑醚菌酯暴露增加了trophocytes中PAS阳性标记（糖原）的强度。在I + P组中也观察到了这种增加。Trophocytes能量储备（糖原）的变化表明这种中性多糖向血淋巴的动员可能受损，这可能会损害暴露个体的健康。此外，oenocytes的变化可能会损害脂肪体执行的解毒功能。这是第一项显示新热带独居蜂亚致死效应的研究，并强调了对本土蜜蜂进行研究的重要性。
