Our experimental study was designed to assess the effects of temperature on food isotopic integrity and trophic fractionations (of carbon and nitrogen stable isotopes: Δ13C and Δ15N) in chironomid larvae. A laboratory experiment was run using Chironomus riparius larvae at 15, 18 and 23°C, and under three pulverized food resources. There were significant changes in the stable isotopic composition of the uneaten food, revealing the difficulty of preventing food microbial degradation in rearing experiments. C/N ratios of chironomid larvae were also affected by temperature, regardless of the food resource, suggesting changes in lipid contents and associated effects on the larval δ13C values. Therefore, differences in calculation methods (with vs. without lipid normalizations, fresh vs. old food isotopic baselines) induced large variability in Δ13C and Δ15N values, but our trophic fractionation estimates were similar to those previously reported in literature. Therefore, we conclude that temperature is not a major driver of the variability in trophic fractionations for chironomid larvae, and stable isotope composition of aquatic consumers can be used in food webs studies under changing temperature conditions. Variability in trophic fractionation estimates should, however, be considered to avoid misinterpretations of food web structure.

中文翻译：

---

实验室实验温度对河岸摇蚊食物同位素完整性和营养分馏的影响

我们的实验研究旨在评估温度对摇蚊幼虫食物同位素完整性和营养分馏（碳和氮稳定同位素：Δ13C 和 Δ15N）的影响。使用河岸摇蚊幼虫在 15、18 和 23°C 和三种粉状食物资源下进行实验室实验。未食用食物的稳定同位素组成发生了显着变化，揭示了饲养实验中防止食物微生物降解的难度。无论食物来源如何，摇蚊幼虫的 C/N 比也受温度的影响，这表明脂质含量的变化和对幼虫 δ13C 值的相关影响。因此，计算方法的差异（有与没有脂质归一化，新鲜与新鲜）。旧的食物同位素基线）引起 Δ13C 和 Δ15N 值的很大变化，但我们的营养分级估计与先前在文献中报道的相似。因此，我们得出结论，温度不是摇蚊幼虫营养成分变化的主要驱动因素，水生消费者的稳定同位素组成可用于温度条件变化下的食物网研究。然而，应考虑营养分级估计的可变性，以避免对食物网结构的误解。水生消费者的稳定同位素组成可用于温度变化条件下的食物网研究。然而，应考虑营养分级估计的可变性，以避免对食物网结构的误解。水生消费者的稳定同位素组成可用于温度变化条件下的食物网研究。然而，应考虑营养分级估计的可变性，以避免对食物网结构的误解。