Alexander Abril, Iglesias-Carrasco Maider, Lozano Miguel, Garcia-Gonzalez Francisco
Lancaster Environment Centre, Lancaster University, Lancaster, United Kingdom.
Department of Ecology and Evolution, Doñana Biological Station, CSIC, Seville, Spain.
Sci Rep. 2025 Jun 4;15(1):19646. doi: 10.1038/s41598-025-00180-6.
A key factor influencing the reproductive success and fitness of an individual is the allocation of resources to reproductive tissue. Previous research has documented positive influences of sexual selection on the evolution of male traits such as testes size. However, few studies have focused on whether sexual selection shapes overall reproductive tissue investment patterns, and even fewer have studied it in both males and females. Furthermore, whether the ecological/demographic context modulates these effects is not known. We used experimental evolution on an insect model system to assess the independent and interactive effects of sexual selection intensity (intense [polygamy] vs. relaxed [monogamy]) and metapopulation structure (absent vs. present) on reproductive tissue investment in both sexes. Counterintuitively, we found that both males and females evolving under monogamy had higher relative reproductive tissue investment than individuals evolving under polygamy. We found no independent effect of metapopulation structure or any interactive effect with sexual selection on reproductive tissue investment of either sex. Our findings suggest that trade-offs between pre- and post-copulatory sexual selection may constrain reproductive tissue investment under intense sexual selection, and that selection under monogamy removes this constraint. Generally, our study underscores the complexities underpinning the evolution of reproductive allocation strategies.
影响个体繁殖成功率和适应性的一个关键因素是对生殖组织的资源分配。先前的研究已证明性选择对雄性特征（如睾丸大小）的进化具有积极影响。然而，很少有研究关注性选择是否塑造了整体生殖组织投资模式，而研究雄性和雌性两者情况的更是少之又少。此外，生态/人口统计学背景是否会调节这些影响尚不清楚。我们在一个昆虫模型系统上进行了实验进化，以评估性选择强度（强烈[一夫多妻制]与宽松[一夫一妻制]）和集合种群结构（不存在与存在）对两性生殖组织投资的独立和交互作用。与直觉相反，我们发现一夫一妻制下进化的雄性和雌性都比一夫多妻制下进化的个体具有更高的相对生殖组织投资。我们没有发现集合种群结构对两性生殖组织投资有独立影响，也没有发现与性选择的任何交互作用。我们的研究结果表明，交配前和交配后性选择之间的权衡可能会限制强烈性选择下的生殖组织投资，而一夫一妻制下的选择消除了这种限制。总体而言，我们的研究强调了生殖分配策略进化背后的复杂性。
