Abstract：
Discussions about environmental risk reassessment of pesticides have grown in the last decades, especially in tropical and subtropical regions since the diversity of bee species in these places is quite different. Stingless bees are highly affected by pesticides, and toxicity information is necessary to include them in the regulatory process of countries that hosts a diversity of these species. Therefore, the present study aimed to evaluate the Median Lethal Concentration (LC50), estimate the Median Lethal Dose (LD50) and compared the sensitivity of three species of stingless bees exposed to the commercial formulation of the neonicotinoid thiamethoxam (TMX). The LD50 was estimated based on the LC50 determined in the present study (LC50 = 0.329 ng a.i./μL for Tetragonisca angustula; 0.624 ng a.i./μL for Scaptotrigona postica, and 0.215 ng a.i./μL for Melipona scutellaris). Considering these data, toxicity endpoints were used to fit species sensitive distribution curves (SSD) and determine the sensitivity ratio. The results showed that all the stingless bees tested are more sensitive to TMX than the Apis mellifera, the model organism used in ecotoxicological tests. Regarding the oral LC50, the most susceptible and most tolerant species were M. scutellaris > T. angustula > S. postica > A. mellifera. Following the same evaluated pattern, for the LD50 (considering the weight of the bees - ng a.i./g bee), we have: M. scutellaris > S. postica > T. angustula > A. mellifera, and without the weight considered (ng a.i./bee): T. angustula > M. scutellaris > S. postica > A. mellifera. The different sensitivities among stingless bee species highlight the importance of inserting more than one surrogate species with a variety of sizes in research and protocol development. Additionally, the research suggests the need to investigate patterns regarding the influence of body mass on pesticide sensitivity among stingless bee species.
摘要：
在过去的几十年里，关于农药环境风险重新评估的讨论越来越多，特别是在热带和亚热带地区，因为这些地方的蜜蜂种类多样性是相当不同的。无刺蜜蜂受到杀虫剂的高度影响，和毒性信息是必要的，以将它们纳入拥有这些物种多样性的国家的监管过程。因此,本研究旨在评估中位致死浓度(LC50)，估计平均致死剂量（LD50），并比较三种无刺蜜蜂暴露于新烟碱噻虫嗪（TMX）商业制剂的敏感性。LD50是根据本研究中确定的LC50进行估算的（Tetragoniscaangustula的LC50=0.329nga.i./μL；Postica的0.624nga.i./μL，和0.215nga.i./μL的Meliponascutellaris）。考虑到这些数据,毒性终点用于拟合物种敏感分布曲线（SSD）并确定敏感性比。结果表明，所有被测的无刺蜜蜂对TMX的敏感性均高于蜜蜂，用于生态毒理学试验的模型生物。关于口服LC50，最易感和最耐受的物种是黄藻分枝杆菌>龙须草>S.potica>A.mellifera。遵循相同的评估模式，对于LD50(考虑蜜蜂的重量-nga.i./g蜜蜂)，我们有：黄衣菌>S.pottica>T.angustula>A.mellifera，并且不考虑重量（nga.i./bee）：T.angustula>M.scutellaris>S.pottica>A.mellifera。无刺蜜蜂物种之间的不同敏感性凸显了在研究和协议开发中插入多种大小的替代物种的重要性。此外,研究表明，有必要研究有关体重对无刺蜜蜂物种中农药敏感性的影响的模式。
