Consumer diet estimation with biotracer-based mixing models provides valuable information about trophic interactions and the dynamics of complex ecosystems. Here, we assessed the performance of four Bayesian and three numerical optimization-based diet estimation methods for estimating the diet composition of herbivorous zooplankton using consumer fatty acid (FA) profiles and resource library consisting of the results of homogeneous diet feeding experiments. The method performance was evaluated in terms of absolute errors, central probability interval checks, the success in identifying the primary resource in the diet, and the ability to detect the absence of resources in the diet. Despite occasional large inconsistencies, all the methods were able to identify the primary resource most of the time. The numerical optimization method QFASA using χ 2 (QFASA-CS) or Kullback­–Leibler (QFASA-KL) distance measures had the smallest absolute errors, most frequently found the primary resource, and adequately detected the absence of resources. While the Bayesian methods usually performed well, some of the methods produced ambiguous results and some had much longer computing times than QFASA. Therefore, we recommend using QFASA-CS or QFASA-KL. Our systematic tests showed that FA models can be used to accurately estimate complex dietary mixtures in herbivorous zooplankton. This article is part of the theme issue ‘The next horizons for lipids as ‘trophic biomarkers': evidence and significance of consumer modification of dietary fatty acids'.

中文翻译：

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草食浮游动物贝叶斯和基于数值优化的饮食估计的比较

使用基于生物示踪剂的混合模型进行消费者饮食估计提供了有关营养相互作用和复杂生态系统动态的宝贵信息。在这里，我们评估了四种贝叶斯和三种基于数值优化的饮食估计方法的性能，用于使用消费者脂肪酸（FA）概况和由均质饮食喂养实验结果组成的资源库来估计草食性浮游动物的饮食组成。该方法的性能根据绝对误差、中心概率区间检查、成功识别饮食中主要资源以及检测饮食中资源缺乏的能力进行评估。尽管偶尔会出现很大的不一致，但所有方法在大多数情况下都能够识别主要资源。使用 χ 的数值优化方法 QFASA2(QFASA-CS) 或 Kullback-Leibler (QFASA-KL) 距离测量的绝对误差最小，最常找到主要资源，并充分检测资源的缺失。虽然贝叶斯方法通常表现良好，但有些方法产生的结果不明确，有些方法的计算时间比 QFASA 长得多。因此，我们建议使用 QFASA-CS 或 QFASA-KL。我们的系统测试表明，FA 模型可用于准确估计草食性浮游动物的复杂膳食混合物。本文是主题“脂质作为‘营养生物标志物’的下一个前景：消费者改变膳食脂肪酸的证据和意义”的一部分。