Aquatic systems worldwide are threatened by the anthropogenic use of synthetic chemicals, including pesticides, pharmaceuticals, and road de‐icers. Exposure to contaminants can alter the behavior, morphology, and physiology of organisms if it occurs during sensitive life stages. For instance, past studies have documented feminization of male amphibians following herbicide exposure and skewed sex ratios among amphibian populations exposed to road salt. However, many of these studies lack the complexities found within natural environments, such as competition with conspecifics or threat of predation, which are also known to influence development. Thus, it is important to understand how anthropogenic and natural stressors interact to alter animal sex ratios. Given the growing concern of secondary salinization of freshwater systems, we exposed larval wood frogs (Rana sylvatica) to either road salt (sodium chloride [NaCl]) or an alternative salt mixture (NaCl, magnesium chloride [MgCl₂], and potassium chloride [KCl]) at 3 concentrations (200, 600, and 1000 mg Cl⁻/L) crossed with 3 biotic stressors (no‐stressor control, competition, or predator cues) to examine their potentially interactive effects on sex. Exposure to biotic stressors and NaCl did not influence wood frog sex ratios. In contrast, tadpole exposure to the intermediate salt mixture concentration significantly reduced the proportion of female frogs. Future studies are needed to determine whether such changes in sex are widespread among sensitive species with complex life cycles, and to assess the consequences of sex ratio changes on long‐term population dynamics. Environ Toxicol Chem 2021;40:231–235. © 2020 SETAC

中文翻译：

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路盐和生物胁迫对两栖动物性别比的综合影响

世界范围内的水生系统受到合成化学品（包括杀虫剂、药物和道路除冰剂）的人为使用的威胁。如果接触污染物发生在敏感的生命阶段，它会改变生物体的行为、形态和生理机能。例如，过去的研究记录了接触除草剂后雄性两栖动物的女性化，以及接触路盐的两栖动物种群的性别比例发生偏差。然而，其中许多研究缺乏在自然环境中发现的复杂性，例如与同类竞争或捕食威胁，这些也已知会影响发展。因此，了解人为和自然压力因素如何相互作用以改变动物性别比例非常重要。鉴于对淡水系统二次盐渍化的日益关注，蛙sylvatica）要么道路盐（氯化钠[NaCl的]）或可替换的盐混合物（NaCl的，氯化镁[氯化镁₂ ]和氯化钾[KCl的]）在3个浓度（200，600和1000毫克氯^- / L) 与 3 种生物压力源（无压力源控制、竞争或捕食者线索）交叉，以检查它们对性的潜在交互影响。暴露于生物压力源和 NaCl 不会影响林蛙的性别比例。相比之下，蝌蚪暴露于中等浓度的盐混合物显着降低了雌性青蛙的比例。未来的研究需要确定这种性别变化是否在具有复杂生命周期的敏感物种中普遍存在，并评估性别比例变化对长期种群动态的影响。环境毒理学化学2021；40：231-235。© 2020 SETAC