Applied Zoology, TU Dresden, Dresden, Germany.
Department of Zoology, Stockholm University, Stockholm, Sweden.
Ecol Lett. 2024 Sep;27(9):e14515. doi: 10.1111/ele.14515.
Size differences between males and females are common across the tree of life (termed sexual size dimorphism; SSD), and have fundamental implications for ecology, life history and behaviour of both sexes. Conventionally, SSD is thought to evolve in response to sex-specific sexual selection but more recent work suggests that ecological processes can also promote sex-differences in size. Here, we provide a global test for the role of sexual selection in the evolution of sexual size dimorphism using data from 77 comparative studies spanning the major classes of the animal kingdom. We show that intense sexual selection typically correlates with male-biased SSD across species. Importantly, pre-copulatory but not post-copulatory sexual selection predicts SSD, suggesting a pervasive role of premating male-male competition and female choice to drive sex differences in body size. Collectively, our findings suggest that pre-copulatory sexual selection plays a major role in the evolution of male-biased SSD.
雄性和雌性之间的大小差异在生命之树上很常见（称为性二型性；SSD），并且对两性的生态学、生活史和行为都有根本的影响。传统上，SSD 被认为是对特定性别的性选择的反应而进化的，但最近的研究表明，生态过程也可以促进大小上的性别差异。在这里，我们使用来自动物王国主要类群的 77 项比较研究的数据，对性选择在性二型性进化中的作用进行了全球检验。我们表明，强烈的性选择通常与物种间的雄性偏斜 SSD 相关。重要的是，前交配而不是后交配的性选择预测 SSD，这表明交配前的雄性-雄性竞争和雌性选择在驱动体型性别差异方面具有普遍作用。总的来说，我们的研究结果表明，前交配性选择在雄性偏斜 SSD 的进化中起着主要作用。
