Universidade Estadual Paulista (UNESP) - "Júlio de Mesquita Filho", Instituto de Biociências (IB), Departamento de Biologia, Centro de Estudos de Insetos Sociais (CEIS), Rio Claro, SP, Brazil.
Universidade Estadual Paulista (UNESP) - "Júlio de Mesquita Filho", Instituto de Biociências (IB), Departamento de Biologia, Centro de Estudos de Insetos Sociais (CEIS), Rio Claro, SP, Brazil.
Ecotoxicol Environ Saf. 2020 Dec 15;206:111395. doi: 10.1016/j.ecoenv.2020.111395. Epub 2020 Oct 5.
Native stingless bees are key pollinators of native flora and important for many crops. However, the loss of natural fragments and exposure to pesticides can hinder the development of colonies and represent a high risk for them. Nevertheless, most studies are conducted with honeybees and there are not many studies on native species, especially in relation to the effects of fungicides on them. Therefore, the objective of this paper is to evaluate the effects of sublethal concentrations of pyraclostrobin, on Melipona scutellaris forager workers. These Brazilian native stingless bees were submitted to continuous oral exposure to three concentrations of pyraclostrobin in sirup: 0.125 ng a.i./µL (P1), 0.025 ng a.i./µL (P2), and 0.005 ng a.i./µL (P3). Histopathological and histochemical parameters of midgut, as well as survival rate were evaluated. All concentrations of fungicide showed an increase in the midgut lesion index and morphological signs of cell death, such as cytoplasmic vacuolizations, presence of atypical nuclei or pyknotic nuclei. Histochemical analyzes revealed a decreased marking of polysaccharides and neutral glycoconjugates both in the villi and in peritrophic membrane in all exposed-groups in relation to control-groups. P1 and P2 groups presented a reduction in total protein marking in digestive cells in relation to control groups. As a consequence of alteration in the midgut, all groups exposed to fungicide showed a reduced survival rate. These findings demonstrate that sublethal concentrations of pyraclostrobin can lead to significant adverse effects in stingless bees. These effects on social native bees indicate the need for reassessment of the safety of fungicides to bees.
本土无刺蜂是本地植物的关键传粉媒介，对许多作物也很重要。然而，自然碎片的丧失和接触杀虫剂会阻碍群体的发展，对它们构成高风险。尽管如此，大多数研究都是针对蜜蜂进行的，而对本土物种的研究并不多，特别是在杀菌剂对它们的影响方面。因此，本文的目的是评估吡唑醚菌酯对觅食工蜂的 Melipona scutellaris 的亚致死浓度的影响。这些巴西本土无刺蜂被连续口服暴露于糖浆中的三种吡唑醚菌酯浓度下：0.125 ng a.i./µL（P1）、0.025 ng a.i./µL（P2）和 0.005 ng a.i./µL（P3）。评估了中肠的组织病理学和组织化学参数以及存活率。所有杀菌剂浓度均显示中肠病变指数增加和细胞死亡的形态学迹象，例如细胞质空泡化、存在异型核或固缩核。组织化学分析显示，与对照组相比，所有暴露组的绒毛和围食膜中的多糖和中性糖缀合物标记均减少。与对照组相比，P1 和 P2 组消化细胞中的总蛋白标记减少。由于中肠的改变，所有接触杀菌剂的组的存活率都降低了。这些发现表明，吡唑醚菌酯的亚致死浓度会对无刺蜂造成重大的不利影响。这些对社会性本土蜂的影响表明，需要重新评估杀菌剂对蜜蜂的安全性。
