Data supporting Francis and Wilkins (2021) Testing the strength and direction of selection on vocal frequency using metabolic scaling theory

This dataset supports the following publication:<br>Francis, C.D &amp; Wilkins, M.R. 2021. Testing the strength and direction of selection on vocal frequency using metabolic scaling theory. Ecosphere.<br>Included are two files: "Francis&amp;Wilkins_Data.csv" are the data supporting the results of the paper and "Francis&amp;Wilkins_README.txt" provides descriptions of the dataset.<br>Below is an abstract from the paper:A major challenge for studies assessing drivers of phenotypic divergence is the statistical comparison of taxa with unique, often unknown, evolutionary histories, and for which there are no clear expected trait values. Because many traits are fundamentally constrained by energy availability, we suggest that trait values predicted by scaling theories such as the metabolic theory of ecology (MTE) can provide baseline expectations. Here, we introduce a metabolic scaling-based approach to test theory involving the direction and magnitude of ecological and sexual selection, using vocal frequency as an example target of selection. First, we demonstrate that MTE predicts the relationship between the natural log of body size and natural log of vocal frequency across 795 bird species, controlling for phylogeny. Family-wide deviations in slope and intercepts from MTE estimates reveal taxa with potentially important differences in physiology or natural history. Further, species-level frequency deviations from MTE expectations are predicted by factors related to ecological and sexual selection and, in some cases, provide evidence that differs from current understanding of the direction of selection and identity of ecological selective agents. For example, our approach lends additional support to the findings from many cross-habitat studies that suggest that dense vegetation selects for lower frequency signals. However, our analysis also suggests that birds in non-forested environments vocalize at frequencies higher than expected based on MTE, prompting intriguing questions about the selective forces in non-forest environments that may act on vocal frequency. Additionally, vocal frequency deviates more strongly from MTE expectations among species with smaller repertoires and those with low levels of sexual dichromatism, complicating the use of these common sexual selection surrogates. Broad application of our metabolic scaling approach might provide an important complementary approach to understanding how selection shapes phenotypic evolution by offering a common baseline across studies and taxa, and providing the basis to explore evolutionary tradeoffs within and among multicomponent and multimodal traits.<br>

本数据集支持以下发表成果：<br>Francis, C.D. 与 Wilkins, M.R. 2021. 《基于代谢缩放理论（metabolic scaling theory）检验鸣声频率的选择强度与方向》. Ecosphere<br>本数据集包含两个文件：`Francis&Wilkins_Data.csv` 为支撑该论文研究结果的原始数据，`Francis&Wilkins_README.txt` 则对本数据集进行了详细说明。<br>以下为该论文的摘要：<br>评估表型分化驱动因素的研究面临一大核心挑战，即对拥有独特且往往未知演化历史的类群开展统计比较，且此类类群并无明确的预期性状值。由于多数性状本质上受能量可获得性的约束，我们提出，由生态代谢理论（metabolic theory of ecology, MTE）这类缩放理论所预测的性状值，可作为基准预期值。本文以鸣声频率作为选择作用的目标示例，提出了一种基于代谢缩放的方法，以检验涉及生态选择（ecological selection）与性选择（sexual selection）的方向和强度的相关理论。<br>首先，我们证明了在控制系统发育（phylogeny）影响的前提下，生态代谢理论可预测795种鸟类的体型自然对数与鸣声频率自然对数之间的相关性。科水平上的斜率与截距相对于生态代谢理论预测值的偏离，揭示了在生理或自然历史特征上存在潜在重要差异的类群。<br>进一步而言，物种水平上的鸣声频率偏离生态代谢理论预期值的程度，可由与生态和性选择相关的因素预测；在部分案例中，该偏离结果还提供了与当前对选择方向及生态选择作用因子认知不同的证据。例如，本研究为多项跨生境研究的结论提供了额外支撑——这些研究认为，植被茂密的生境会选择偏向低频鸣声信号。但本分析同时表明，非森林生境中的鸟类的鸣声频率高于生态代谢理论的预期值，这引发了一系列关于非森林生境中可能作用于鸣声频率的选择压力的有趣问题。<br>此外，鸣声曲目（vocal repertoires）较少以及性二色性（sexual dichromatism）程度较低的物种，其鸣声频率偏离生态代谢理论预期值的程度更为显著，这使得这类常见的性选择替代指标的应用变得更为复杂。<br>将本研究提出的代谢缩放方法进行广泛应用，可为理解选择如何塑造表型演化提供重要的互补路径：该方法可为不同研究与类群提供统一的基准，并为探索多组分、多模态性状内部及之间的演化权衡关系奠定基础。