Evolutionary Stress Ecology and Ecotoxicology, University of Leuven, Charles Deberiotstraat 32, B-3000 Leuven, Belgium.
Evolutionary Stress Ecology and Ecotoxicology, University of Leuven, Charles Deberiotstraat 32, B-3000 Leuven, Belgium.
Sci Total Environ. 2018 Mar 15;618:60-69. doi: 10.1016/j.scitotenv.2017.10.311. Epub 2017 Nov 8.
To predict the impact of pesticides in a warming world we need to know how species differ in the interaction pathways between pesticides and warming. Trait-based approaches have been successful in identifying the 'pace of life' and body size as predictors of sensitivity to pesticides among distantly related species. However, it remains to be tested whether these traits allow predicting differences in sensitivity to pesticides between closely related species, and in the strength of the interaction pathways between pesticides and warming. We tested the effects of multiple pulses of chlorpyrifos (allowing accumulation) under warming on key life history traits, heat tolerance (CTmax) and physiology of two congeneric damselfly species: the fast-paced (fast growth and development, high metabolic rate), small Ischnura pumilio and the slow-paced, large I. elegans. Chlorpyrifos reduced survival and growth, but contrary to current trait-based predictions I. pumilio was 8× less sensitive than I. elegans. The lower sensitivity of I. pumilio could be explained by a higher fat content, and higher activities of acetylcholinesterase and of detoxifying and anti-oxidant enzymes. While for I. pumilio the effect of chlorpyrifos was small and did not depend on temperature, for I. elegans the impact was higher at 20°C compared to 24°C. This matches the higher pesticide accumulation in the water after multiple pulses at 20°C than at 24°C. The expected reduction in heat tolerance after pesticide exposure was present in I. elegans but not in I. pumilio. Our results demonstrate that closely related species can have very different sensitivities to a pesticide resulting in species-specific support for the "toxicant-induced climate change sensitivity" and the "climate-induced toxicant sensitivity" interaction pathways. Our results highlight that trait-based approaches can be strengthened by integrating physiological traits.
为了预测在变暖世界中农药的影响，我们需要知道物种在农药与变暖之间的相互作用途径上的差异。基于特征的方法已经成功地确定了“生活节奏”和体型作为预测不同亲缘物种对农药敏感性的指标。然而，这些特征是否能够预测亲缘物种之间对农药敏感性的差异，以及农药与变暖之间相互作用途径的强度，仍有待检验。我们测试了在变暖条件下，多次施用氯吡硫磷（允许积累）对两个同属蜻蜓物种关键生活史特征、耐热性（CTmax）和生理机能的影响：快速生活节奏（快速生长和发育、高代谢率）、体型较小的 I. pumilio 和缓慢生活节奏、体型较大的 I. elegans。氯吡硫磷降低了存活率和生长率，但与当前基于特征的预测相反，I. pumilio 的敏感性比 I. elegans 低 8 倍。I. pumilio 的敏感性较低可能是由于脂肪含量较高，以及乙酰胆碱酯酶和解毒及抗氧化酶的活性较高。虽然氯吡硫磷对 I. pumilio 的影响较小且不依赖于温度，但对 I. elegans 的影响在 20°C 时比在 24°C 时更高。这与在 20°C 下多次脉冲后，水中农药积累量高于 24°C 的情况相符。在 I. elegans 中观察到暴露于农药后耐热性降低，但在 I. pumilio 中没有。我们的研究结果表明，亲缘关系密切的物种对农药可能具有非常不同的敏感性，从而为“有毒物质引起的气候变化敏感性”和“气候变化引起的有毒物质敏感性”相互作用途径提供了特定物种的支持。我们的研究结果强调，基于特征的方法可以通过整合生理特征得到加强。
