Data from: Experimental reduction of intromittent organ length reduces male reproductive success in a bug

Data all.xlsx:
All data from processus manipulation experiments 1-3.

CT scan files.zip:
Raw slice images from CT scans, and VAXML files and 3D pdfs of 3D reconstructions.

It is now clear in many species that male and female genital evolution has been shaped by sexual selection. However, it has historically been difficult to confirm correlations between morphology and fitness, as genital traits are complex and manipulation tends to impair function significantly. In this study, we investigate the functional morphology of the elongate male intromittent organ (or processus) of the seed bug Lygaeus simulans, in two ways. We first use micro-computed tomography (micro-CT) and flash-freezing to reconstruct in high resolution the interaction between the male intromittent organ and the female internal reproductive anatomy during mating. We successfully trace the path of the male processus inside the female reproductive tract. We then confirm that male processus length influences sperm transfer by experimental ablation and show that males with shortened processi have significantly reduced post-copulatory reproductive success. Importantly, male insemination function is not affected by this manipulation per se. We thus present rare, direct experimental evidence that an internal genital trait functions to increase reproductive success and show that, with appropriate staining, micro-CT is an excellent tool for investigating the functional morphology of insect genitalia during copulation.

Data all.xlsx:
所有来自插入器官操控实验1至3的实验数据。

CT scan files.zip:
CT扫描原始切片图像，以及三维重建的VAXML文件与3D PDF文件。

目前学界已明确，诸多物种的雌雄生殖器演化均由性选择塑造。然而长期以来，受限于生殖器性状结构复杂且操控操作往往会显著损伤其功能，难以验证生殖器形态与适合度之间的相关性。本研究从两个维度探究模拟长蝽（Lygaeus simulans）的长形雄性插入器官（或称processus）的功能形态学：其一，通过显微计算机断层扫描（micro-computed tomography, micro-CT）与快速冷冻技术，以高分辨率重建交配过程中雄性插入器官与雌性内生殖解剖结构的相互作用，成功追踪到雄性processus在雌性生殖道内的行进路径；其二，通过实验性切除验证雄性processus长度对精子转移的影响，发现processus缩短的雄性其交配后繁殖成功率显著降低。值得注意的是，此类操控本身并不会影响雄性的授精功能。因此本研究提供了罕见的直接实验证据，证明内部生殖器性状可提升繁殖成功率；同时表明，经恰当染色后，micro-CT是探究昆虫交配过程中生殖器功能形态学的优质工具。