Daphnia magna is a common model organism for ecotoxicological testing. In regulatory guidelines, the classical tested endpoints are immobilization and reproduction. In order to detect other sublethal effects potentially more sensitive endpoints are required. Behavioral endpoints are one approach in environmental risk assessment for more sensitive endpoints and monitoring of water quality, demonstrating ecological relevance since altered behavior can impact reproduction and survival, yet they are rarely included in risk assessment. In literature, several chemicals have shown to alter swimming behavior of D. magna. The objective of our study was to identify suitable behavioral endpoints regarding sensitivity and applicability under short-term and long-term exposure to selected insecticides in environmentally relevant concentrations and potential generational effects of insecticide exposure. The investigated endpoints were locomotor activity, spatial orientation and predator avoidance behavior. Neonate D. magna were exposed to the insecticides imidacloprid, thiacloprid and fipronil for 48 hours during short-term exposure and for 14 days during long-term exposure. In a second step, for the investigation of generational effects, behavioral alterations of neonates born under insecticide exposure were tested. The investigated insecticides altered the swimming patterns of D. magna, with statistically significant effects observed at lower concentrations compared to the classical endpoints immobility and reproduction. Thus, the current study demonstrates that the assessment of behavioral endpoints helps in informing Mode of Action (MoA)-specific risk assessment. SYNOPSIS: Behavioral endpoints have recently drawn attention as more sensitive endpoints than regulatory relevant endpoints like immobilization or reproduction. This study identifies behavioral effects during short-term and long-term exposures and generational effects of insecticides with environmental relevance in the non-target organism Daphnia magna.

Keywords: Behavioral ecotoxicology; Behavioral tracking; Daphnia magna; Locomotion; Predator avoidance; Spatial orientation; Swimming behavior; Swimming parameters; Toxicity assessment.

Copyright © 2025 The Authors. Published by Elsevier Inc. All rights reserved.

大溞（Daphnia magna）是生态毒理学测试中常用的模式生物。在监管指南中，经典的测试终点是麻痹和繁殖。为了检测潜在的亚致死效应，需要更敏感的测试指标。行为终点是环境风险评估中用于监测水质和发现更敏感终点的一种方法，因为改变的行为可能会影响繁殖和生存，尽管它们很少被纳入风险评估中。在文献中，有几种化学物质已被证明可以改变大溞的游泳行为。本研究的目标是在短期和长期接触选定杀虫剂以及潜在世代效应的情况下，识别合适的行为终点指标，这些杀虫剂在环境相关浓度下进行测试。研究的终点包括运动活性、空间定向能力和捕食者回避行为。新生的大溞在短期暴露中接触到imidacloprid（吡虫啉）、thiacloprid（噻虫嗪）和fipronil（氟虫腈），持续48小时；在长期暴露中，接触时间为14天。在第二阶段，为了研究世代效应，测试了在杀虫剂暴露下出生的新生溞的行为变化。所调查的杀虫剂改变了大溞的游泳模式，并且与经典的终点指标麻痹和繁殖相比，在较低浓度时就观察到统计学上显著的效果。因此，本研究表明评估行为终点有助于告知特定作用机制（Mode of Action, MoA）的风险评估。

关键词：

行为生态毒理学；行为跟踪；Daphnia magna；运动活性；捕食者回避；空间定向能力；游泳行为；游泳参数；毒性评估。

版权所有 © 2025 作者。由Elsevier Inc.出版，保留所有权利。