Complete raw data.

Many organisms show flexible resource allocation to adjust for optimal reproductive investment across different environments. How such reproductive plasticity occurs in hermaphroditic organisms—allocating resources to both oocytes and sperm—are central questions of sex allocation research. Self-fertilizing hermaphrodites of the androdioecious nematode Caenorhabditis elegans exhibit a sequential transition from spermatogenesis to oogenesis, so the extent of self-sperm production determines both fertilization onset and lifetime reproductive potential under selfing. Despite this key role, it remains largely unclear whether such sequential hermaphrodites flexibly adjust sperm production to optimize self-fertilization across different environments. Here we directly quantified plasticity in C. elegans hermaphrodite self-sperm production in diverse experimental environments. We found that: (a) Sperm production was developmentally plastic, but such changes did not consistently translate into changes in self-progeny number, suggesting C. elegans self-fecundity is likely often oocyte-limited rather than sperm-limited; (b) Contrary to expectations, plastically increased sperm production did not delay the onset of fertilization across various environments; (c) Subtle environmental challenges, such as mild dietary restriction, did not affect sperm production but had a significant impact on developmental time, age at reproductive maturity, and germline proliferation. This emphasizes the relative environmental insensitivity of sperm production compared to other reproductive traits in hermaphrodites. (d) Plasticity in sperm and germline traits varied by genetic background, with notable differences between the laboratory strain N2 and wild strains. These findings contribute to our understanding of reproductive plasticity in C. elegans and the developmental plasticity of sex allocation in sequential hermaphrodites.诸多生物会通过灵活的资源分配策略，在不同环境中调整生殖投入以实现最优适配。在雌雄同体生物中，这类生殖可塑性如何实现——即同时向卵母细胞与精子分配资源——是性分配研究的核心议题之一。雄两性同体共存的线虫物种秀丽隐杆线虫（Caenorhabditis elegans）的自体受精雌雄同体个体，会经历从精子发生向卵发生的顺序性转变，因此自体精子的产生量直接决定了自体受精时的受精起始时间与终生生殖潜能。尽管自体精子发挥如此关键的作用，但这类顺序性雌雄同体生物是否会在不同环境中灵活调整精子产生量以优化自体受精效率，目前仍尚未明确。本研究针对多种实验环境下的秀丽隐杆线虫（C. elegans）雌雄同体个体的自体精子产生可塑性进行了直接量化分析，结果发现：(a) 精子产生量具有发育可塑性，但此类变化并未稳定转化为自体子代数量的改变，这表明秀丽隐杆线虫的自体生殖力通常更易受卵母细胞数量限制，而非精子数量限制；(b) 与预期相悖的是，在各类环境中，可塑性提升的精子产生量并未延迟受精起始时间；(c) 轻度饮食限制这类温和的环境胁迫，并不会影响精子产生量，但会显著改变发育时长、生殖成熟年龄与生殖系增殖能力。这一结果凸显出，相较于雌雄同体的其他生殖性状，精子产生量对环境变化的相对不敏感性；(d) 精子与生殖系性状的可塑性会因遗传背景而异，实验室标准菌株N2与野生菌株之间存在显著差异。本研究结果有助于加深我们对秀丽隐杆线虫生殖可塑性，以及顺序性雌雄同体生物性分配发育可塑性的理解。