Reproductive output of old males is limited by seminal fluid, not sperm number

Male reproductive senescence is typically characterised by a decline in the number of sperm produced and transferred by old males, a phenomenon that may be exacerbated in polygynous species where males mate-multiply. However, males also transfer seminal fluid to females, and little is known about its role in modulating male reproductive senescence. Here, we explore the contributions of sperm and seminal fluid towards male reproductive senescence in a series of sequential matings, using Drosophila melanogaster. As expected, old males produce fewer offspring than young males. However, this pattern is not driven by sperm limitation: old males have more sperm and transfer similar numbers to females, compared to young males. Instead, females storing fewer sperm of old males compared to that of young males, over a long-term, drives male reproductive senescence. We are able to mitigate the age-related decline in male reproductive output by supplementing females with the seminal fluid of a youn..., We conducted experiments and colelcted data directly through observations., , # Reproductive output of old males is limited by seminal fluid, not sperm number Note: In the dataset, the labels for Experiment ID are contrasting the paper: in the dataset, Experiment B is actually experiment C from the paper, and experiment C in the dataset is experiment B in the paper. [https://doi.org/10.5061/dryad.mpg4f4r99](https://doi.org/10.5061/dryad.mpg4f4r99) ## Description of the data and file structure 1\. BG.csv : csv data file for plotting batemans’s gradient in R code 2\. Stripping simple.rmd: R code needed to run all analysis (all data provided on OSF) 3\. Stripping: data from experiments A and C on reproductive output 4\. gfp_f.csv : data on sperm numbers inside females after dissection of females, to be used in R code. Also has data on the numbers of offspring produced by females over 24 hours of egg laying, in a male’s mating sequence, for experiment B. 5\. gfp_m.csv : data on sperm numbers inside male SV and size of male Accessory glands...雄性生殖衰老通常以老年雄性产生并传递的精子数量下降为典型特征，在雄性多次交配的多配制物种中，这一现象可能会进一步加剧。然而，雄性还会向雌性传递精浆，目前学界对其在调控雄性生殖衰老中的作用尚不清楚。本研究以黑腹果蝇（Drosophila melanogaster）为实验模型，通过一系列连续交配实验，探究精子与精浆对雄性生殖衰老的具体贡献。 正如预期，老年雄性产生的后代数量少于年轻雄性。但该模式并非由精子限制所驱动：与年轻雄性相比，老年雄性拥有更多精子，且向雌性传递的精子数量并无显著差异。相反，长期观察发现，雌性储存的老年雄性精子数量显著低于年轻雄性的精子，这才是导致雄性生殖衰老的核心原因。我们可通过向雌性补充年轻雄性的精浆，缓解雄性生殖产出随年龄增长的衰退。本研究通过直接观察开展实验并收集相关数据。 # 老年雄性的生殖产出受精浆限制，而非精子数量 注意：本数据集的实验ID标注与论文存在不一致：数据集中的实验B实际上对应论文中的实验C，而数据集中的实验C则对应论文中的实验B。 [https://doi.org/10.5061/dryad.mpg4f4r99](https://doi.org/10.5061/dryad.mpg4f4r99) ## 数据与文件结构说明 1. BG.csv：用于在R代码中绘制贝特曼梯度的CSV数据文件 2. Stripping simple.rmd：用于运行所有分析的R代码（所有数据已上传至开放科学框架（Open Science Framework, OSF）） 3. Stripping：来自实验A与实验C的生殖产出相关数据 4. gfp_f.csv：包含雌性解剖后体内精子数量的相关数据，可用于R代码分析；同时收录了实验B中，雌性在雄性交配序列内24小时产卵期所产生的后代数量数据。 5. gfp_m.csv：包含雄性储精囊（seminal vesicle, SV）内精子数量与雄性副腺（accessory glands）大小的相关数据……