Mentesana Lucia, Hau Michaela, D'Amelio Pietro B, Adreani Nicolas M, Sánchez-Tójar Alfredo
Max Planck Institute for Biological Intelligence, Germany.
Department of Evolutionary Biology, Faculty of Biology, Bielefeld university, Bielefeld, Germany.
Ecol Lett. 2025 Mar;28(3):e70100. doi: 10.1111/ele.70100.
Egg-laying species are key models for understanding the adaptive significance of maternal effects, with egg hormones proposed as an important underlying mechanism. However, even thirty years after their discovery, the evolutionary consequences of hormone-mediated maternal effects remain unclear. Using evidence synthesis, we tested the extent to which increased prenatal maternal hormone deposition in eggs relates to fitness in wild birds (19 species, 438 effect sizes and 57 studies). Egg androgens, glucocorticoids, and thyroid hormones showed an overall near-zero mean effect for both maternal and offspring fitness proxies. However, heterogeneity was high, suggesting that egg hormone effects on fitness are context-dependent. Hormone type and age did not explain much of the observed variance, nor did methodological factors such as the type of study or experimental design. Heterogeneity decomposition showed that differences in effect sizes were mostly driven by within-study variability and phylogenetic relationships. Our study provides the most comprehensive investigation to date of the relationship between egg hormones and fitness in vertebrates. By synthesising current knowledge, we aim to overcome theoretical shortcomings in the field of maternal effects via egg hormone deposition and inspire new research into its many intriguing aspects.
产卵物种是理解母体效应适应性意义的关键模型，卵内激素被认为是一个重要的潜在机制。然而，即使在它们被发现30年后，激素介导的母体效应的进化后果仍不清楚。通过证据综合分析，我们测试了卵内产前母体激素沉积增加与野生鸟类（19个物种、438个效应量和57项研究）适应性之间的关联程度。卵雄激素、糖皮质激素和甲状腺激素对母体和后代适应性指标的总体平均效应接近零。然而，异质性很高，这表明卵激素对适应性的影响取决于具体情况。激素类型和年龄并不能解释所观察到的大部分变异，研究类型或实验设计等方法学因素也不能解释。异质性分解表明，效应量的差异主要由研究内部的变异性和系统发育关系驱动。我们的研究提供了迄今为止对脊椎动物卵激素与适应性之间关系最全面的调查。通过综合现有知识，我们旨在克服通过卵激素沉积产生的母体效应领域的理论缺陷，并激发对其许多有趣方面的新研究。
