Monitoring the adverse effects of environmental contaminants on the reproduction of invertebrate species in the field remains a challenge in aquatic ecotoxicology. To meet the need for reliable tools for in situ toxicity assessment, we present the first part of a methodological study of the in situ implementation of a reproductive bioassay in Gammarus previously developed for screening the toxicity of chemical compounds during laboratory exposure. To ensure the correct interpretation of the modulation of reproductive markers (molting, fecundity, follicle growth, and embryonic development) in uncontrolled environmental conditions, we experimentally assessed and statistically modeled the variability in the female reproductive cycle during laboratory exposure under several temperature and water hardness conditions. Whereas water hardness did not influence the reproductive cycle, the significant accelerating effect of temperature on the dynamics of molting and marsupial development was finely modeled, by detailing the influence of temperature on the probability of transition between all molt and embryonic stages along the female cycle. In addition, no effect of temperature or water hardness was detected on the number of oocytes and embryos carried by females. Furthermore, the finding that the relative durations of the first 4 molt and embryonic stages are constant whatever the temperature makes it possible to predict the molting dynamics in fluctuating temperature conditions. Because this could allow us to take into account the confounding influence of temperature on the measurement of reproductive markers, the implications of these findings for an optimal in situ implementation of the reproductive bioassay with G. fossarum are discussed. The relevance of this modeling approach during in situ implementation is tested in a companion study. Environ Toxicol Chem 2020;39:667-677. © 2019 SETAC.

中文翻译：

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笼中γ-镰刀菌（甲壳纲）的原位生殖生物测定：第1部分-测量温度和水硬度的混杂影响。

在水生生态毒理学中，监测环境污染物对无脊椎动物物种繁殖的不利影响仍然是一个挑战。为满足对可靠的原位毒性评估工具的需求，我们介绍了以前在伽玛鲁斯中进行生殖生物测定的原位实施方法学研究的第一部分，该方法先前已开发出来用于筛选实验室暴露期间化学物质的毒性。为了确保在不受控制的环境条件下正确解释生殖标志物的调制（蜕皮，繁殖力，卵泡生长和胚胎发育），我们在几种温度和水硬度下，通过实验评估和统计学模拟了实验室暴露期间雌性生殖周期的变异性。情况。尽管水的硬度不影响生殖周期，但通过详细说明温度对整个雌性周期内蜕皮和胚芽期过渡的可能性的影响，可以很好地模拟温度对蜕皮和有袋动物发育动力学的显着加速作用。此外，未检测到温度或水硬度对雌性携带的卵母细胞和胚胎数量的影响。此外，无论温度如何，前四个蜕皮阶段和胚胎阶段的相对持续时间都是恒定的，这使得可以预测温度变化情况下的蜕皮动力学。因为这可以让我们考虑温度对生殖标记物测量的混杂影响，讨论了这些发现对以最佳方式原产地进行G. fossarum生殖生物测定的意义。在伴随研究中测试了这种建模方法在原位实施过程中的相关性。Environ Toxicol Chem 2020； 39：667-677。©2019 SETAC。