Centre d'Écologie Fonctionnelle et Évolutive, UMR 5175 CNRS, Université de Montpellier, École Pratique des Hautes Études, Montpellier, France.
Applied Zoology, Technical University Dresden, Zellescher Weg 20b, Dresden 01062, Germany.
Biol Lett. 2021 Sep;17(9):20210251. doi: 10.1098/rsbl.2021.0251. Epub 2021 Sep 15.
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二型性（SSD）进化的关键力量。然而，根据所研究的分类群和用于量化性选择的方法，雄性性选择与雄性偏斜 SSD 之间存在正相关关系的实证证据存在混合支持。在这里，我们提出了一种元分析方法，考虑到系统发育非独立性，以测试在广泛的动物分类群中，预先交配性选择的机会和强度的标准化指标如何与 SSD 相关，这些分类群包括来自 59 个物种的高达 95 个效应大小。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 Bateman 梯度的性别差异呈弱且统计上不显著的关系。这些发现表明，在广泛的系统发育背景下，预先交配性选择对 SSD 的进化作用有限。
