Departamento de Biologia, CEIS-Centro de Estudos de Insetos Sociais, Av. 24-A, 1515, CEP: 13506-900, UNESP-Rio Claro, SP, Brazil.
J Econ Entomol. 2010 Jun;103(3):676-90. doi: 10.1603/ec09159.
The current study compared the toxicity of different concentrations of boric acid in adult workers of Atta sexdens rubropilosa Forel (Hymenoptera: Formicidae), with toxicological bioassays, and examining the dose-dependent and time-dependent histopathological changes, of the midgut, Malpighian tubules, and postpharyngeal glands. Our results revealed the importance of conducting toxicological bioassays combined with morphological analyses of the organs of ants chronically exposed to insecticides used in commercial ant baits. In vitro bioassays showed that boric acid significantly decreases the survivorship of workers regardless of concentration, whereas the morphological data suggested progressive dose-dependent and time-dependent changes in the organs examined, which were evident in the midgut. The midgut is the first organ to be affected, followed by the postpharyngeal gland and Malpighian tubules. This sequence is in agreement with the absorption pathway of this chemical compound in the midgut, its transference to the hemolymph, possibly reaching the postpharyngeal glands, and excretion by the Malpighian tubules. These progressive changes might be due to the cumulative and delayed effect of boric acid. Our findings provide important information for the understanding of the action of boric acid in ant baits in direct and indirect target organs.
本研究比较了不同浓度硼酸对成年拟黑多刺蚁（膜翅目：蚁科）的毒性，采用毒理学生物测定法，并观察了中肠、马氏管和咽后腺的剂量依赖性和时间依赖性组织病理学变化。我们的结果表明，对于长期接触商业蚂蚁毒饵中使用的杀虫剂的蚂蚁，进行毒理学生物测定并结合对其器官进行形态分析非常重要。体外生物测定表明，硼酸无论浓度如何，都会显著降低工蚁的存活率，而形态学数据表明，所检查的器官存在渐进的剂量和时间依赖性变化，中肠最为明显。中肠是第一个受到影响的器官，其次是咽后腺和马氏管。这一顺序与该化合物在中肠中的吸收途径、向血淋巴的转移、可能到达咽后腺以及通过马氏管的排泄一致。这些渐进性变化可能是由于硼酸的累积和延迟效应。我们的研究结果为理解硼酸在蚂蚁毒饵中的直接和间接靶器官中的作用提供了重要信息。
