Sexual selection is often considered as a critical evolutionary force promoting sexual size dimorphism (SSD) in animals. However, empirical evidence for a positive relationship between sexual selection on males and male-biased SSD received mixed support depending on the studied taxonomic group and on the method used to quantify sexual selection. Here, we present a meta-analytic approach accounting for phylogenetic non-independence to test how standardized metrics of the opportunity and strength of pre-copulatory sexual selection relate to SSD across a broad range of animal taxa comprising up to 95 effect sizes from 59 species. We found that SSD based on length measurements was correlated with the sex difference in the opportunity for sexual selection but showed a weak and statistically non-significant relationship with the sex difference in the Bateman gradient. These findings suggest that pre-copulatory sexual selection plays a limited role for the evolution of SSD in a broad phylogenetic context.

性选择通常被认为是促进动物性大小二态性（SSD）的关键进化力量。然而，根据研究的分类群和用于量化性选择的方法，男性性选择和偏向男性的 SSD 之间存在正相关的经验证据得到了不同的支持。在这里，我们提出了一种解释系统发育非独立性的荟萃分析方法，以测试交配前性选择的机会和强度的标准化指标如何与包括来自 59 个物种的多达 95 个效应大小的广泛动物类群中的 SSD 相关。 。我们发现基于长度测量的 SSD 与性选择机会的性别差异相关，但与贝特曼梯度中的性别差异表现出微弱且统计上不显着的关系。这些发现表明，在广泛的系统发育背景下，交配前性选择对 SSD 的进化发挥的作用有限。