Department of Biosciences , University of Oslo , P.O box 1066 Blindern, 0316 Oslo , Norway.
Environ Sci Technol. 2018 Nov 20;52(22):13535-13542. doi: 10.1021/acs.est.8b03685. Epub 2018 Oct 31.
To examine whether natural stressors like predation risk affect responses to anthropogenic contaminants, we exposed nauplii of the copepod Tigriopus brevicornis to chemical cues from fish (kairomones) and copper (Cu). We tested effects of these treatments, singly and combined, on copepod age and size at maturity, and development stage sensitivity, while controlling for effects of genetic heterogeneity (clutch identity). Predation risk, Cu and clutch identity interacted in their effect on development time. Predation risk alone had minor effects, but potentiated Cu toxicity in the combined treatment by doubling the delay in age at maturity, as compared to Cu exposure alone. This potentiating effect on developmental delay appeared already at the first copepodite stage. The specific strength of response varied among nauplii from different females' clutches. There were no differences in copepod size at maturity among treatments. We did, however, find an interaction between the effect of Cu and clutch identity on copepod growth. Our results demonstrate the importance of ecological interactions for potentiating the toxicity of environmental contaminants. We also demonstrate the need to consider genetic heterogeneity in ecotoxicology. Natural variation in stressor responses has implications for the interpretation of results from toxicological studies using single-clone or inbred culture populations.
为了研究自然应激源（如捕食风险）是否会影响对人为污染物的反应，我们将桡足类的桡足幼体暴露于鱼类（信息素）和铜（Cu）的化学信号中。我们测试了这些处理方式单独和组合对桡足类成熟时的年龄和大小以及发育阶段敏感性的影响，同时控制了遗传异质性（卵鞘身份）的影响。捕食风险、Cu 和卵鞘身份在发育时间上的相互作用。捕食风险本身的影响较小，但在联合处理中增强了 Cu 的毒性，与单独暴露于 Cu 相比，成熟时的年龄延迟了一倍。这种对发育延迟的增强作用在第一桡足幼体阶段就已经出现。来自不同雌性卵鞘的桡足幼体的反应强度存在差异。在成熟的桡足类中，各处理之间没有大小差异。然而，我们确实发现 Cu 的作用与卵鞘身份对桡足类生长的影响之间存在相互作用。我们的结果表明，生态相互作用对于增强环境污染物的毒性非常重要。我们还表明，在生态毒理学中需要考虑遗传异质性。在应激反应方面的自然变异会影响使用单克隆或近交培养种群进行毒理学研究的结果的解释。
