Behavioral endpoints are important parameters to assess the effects of toxicants on aquatic animals. These endpoints are useful in ecotoxicology because several toxicants modify the animal behavior, which may cause adverse effects at higher levels of ecological organization. However, for the development of new bioassays and for including the behavior in ecotoxicological risk assessment, the comparison of sensitivity between different behavioral endpoints is necessary. Additionally, some toxicants remain in aquatic environments for a few hours or days, which may lead to animal recovery after toxicant exposure. Our study aimed to assess the effect of unionized ammonia on the movement and feeding behaviors of the aquatic gastropod Potamopyrgus antipodarum (Tateidae, Mollusca) and its recovery after exposure. Four treatments were used: a control and three nominal concentrations of unionized ammonia (0.25, 0.5 and 1 mg N-NH₃/L). Each treatment was replicated eight times, with six animals in each replicate. Animals were exposed to unionized ammonia for 48 h (exposure period) and, subsequently, to control water for 144 h (post-exposure period). Two movement variables were monitored without food and five feeding behavioral variables were monitored in the presence of food. Some of the feeding behavioral variables showed higher sensitivity (LOEC = 0.25–0.5 mg N-NH₃/L) than the movement behavior variables monitored without food (LOEC = 1 mg N-NH₃/L). After exposure to unionized ammonia, animals showed a recovery of most behavioral endpoints. The inclusion of post-exposure period and feeding behaviors in bioassays may make studies more realistic, which is crucial for a proper ecotoxicological risk assessment.

行为终点是评估毒物对水生动物影响的重要参数。这些端点在生态毒理学中很有用，因为有几种毒物会改变动物的行为，这可能会对更高水平的生态组织造成不利影响。然而，为了开发新的生物测定并将行为纳入生态毒理学风险评估，需要比较不同行为终点之间的敏感性。此外，一些毒物会在水生环境中停留数小时或数天，这可能导致动物在接触毒物后恢复。我们的研究旨在评估非离子氨对水生腹足动物Potamopyrgus antipodarum的运动和摄食行为的影响（Tateidae，软体动物）及其暴露后的恢复。使用了四种处理：一个对照和三个标称浓度的非离子氨（0.25、0.5 和 1 mg N-NH ₃ /L）。每个处理重复八次，每个重复六只动物。动物暴露于非离子氨中 48 小时（暴露期），随后控制水 144 小时（暴露后期）。在没有食物的情况下监测两个运动变量，在有食物的情况下监测五个喂养行为变量。一些摄食行为变量的敏感性（LOEC = 0.25–0.5 mg N-NH ₃ /L）比无食物监测的运动行为变量（LOEC = 1 mg N-NH ₃/L)。在暴露于非离子氨后，动物表现出大多数行为终点的恢复。在生物测定中包含暴露后期和摄食行为可能会使研究更加现实，这对于适当的生态毒理学风险评估至关重要。