Isopods are macrodecomposers in terrestrial ecosystems, contributing to soil organic matter breakdown and nutrient cycling. They have been considered sensitive in laboratory tests designed to evaluate contaminants effects and are considered likely candidates to have a standardized protocol for ecotoxicity tests. For this purpose, a reference substance should be proposed as positive control in laboratory tests. This work aimed to evaluate the avoidance behaviour of the isopod species Porcellio dilatatus to boric acid (H₃BO₃; BA). Interlaboratory comparison tests were carried out based on the ISO guideline for earthworms, using tropical artificial soil as substrate, in the concentrations of 0, 125, 250, 500, 750, 1000, 1300 and 1800 mg BA kg⁻¹ soil. Avoidance behaviour was evaluated in group (six organisms per replicate) and in individual tests (one organism per replicate), in dual-section plastic boxes, which received control soil (not contaminated) in one side and tested soil (with BA) in another one. The percentage of organisms in each side was recorded after 48 h, and data were analysed using Fisher exact test (p < 0.05) and t-test. Results showed significant avoidance response in individual tests at 250 mg kg⁻¹ and in group tests at 500 mg kg⁻¹. Limited habitat function (< 20% of organisms) for both tests and laboratories were observed at the highest tested concentration of 1800 mg kg⁻¹, indicating the low sensitivity of this species to BA in avoidance tests, if compared to other substances in literature. Results showed that BA can be used as reference substance until a better option will be proposed.

等足动物是陆地生态系统中的大型分解物，有助于土壤有机物分解和养分循环。它们在旨在评估污染物影响的实验室测试中被认为是敏感的，并且被认为具有生态毒性测试的标准化方案的可能候选者。为此，应在实验室测试中提出参考物质作为阳性对照。这项工作旨在评估等足类物种Pircellio dilatatus对硼酸（H ₃ BO ₃； BA）的回避行为。根据热带ISO的ISO准则，以热带人工土壤为基质，进行了实验室间的比较试验，其浓度为0、125、250、500、750、1000、1300和1800 mg BA kg ^-1泥。在组（每组六个生物）和个别测试（每组一个生物）中，在两节塑料盒中评估回避行为，塑料盒的一侧接受对照土壤（未污染），另一侧接受测试土壤（含BA）一。在48小时后记录每一侧中的生物体的百分比，并使用Fisher精确检验（p ＜0.05）和t检验对数据进行分析。结果显示，在250 mg kg ^-1的单独测试和500 mg kg ^-1的分组测试中，显着的回避反应。在最高测试浓度为1800 mg kg ^{-1的情况下}，在测试和实验室中均观察到有限的栖息地功能（<20％的生物体），表明该物种在回避测试中对BA的敏感性较低（如果与文献中的其他物质相比）。结果表明，BA可以用作参考物质，直到提出更好的选择为止。