The thermal environment of sperm affects offspring success: a test of the anticipatory paternal effects hypothesis in a broadcast spawner

There has been an explosion of recent evidence that environments experienced by fathers or their ejaculates can influence offspring phenotypes (paternal effects). However, little is known about whether such effects are adaptive, which would have far-reaching implications for the many species facing rapidly changing environments. For example, some arguments suggest paternal effects might be a source of cross-generational plasticity, preparing offspring to face similar conditions to their father (anticipatory hypothesis). Alternatively, ejaculate-mediated effects on offspring may be non-adaptive by-products of stress. Here, we conduct an experiment to distinguish between these predictions, exposing ejaculates of the externally fertilizing mussel Mytilus galloprovincialis to ambient (19 °C) and high (24 °C) temperatures, then rearing offspring groups in temperatures that match and mismatch those of sperm. We find that, overall, high-treated sperm induced higher rates of normal offspring development, and higher success in transitioning to second-stage larvae, which may represent adaptive epigenetic changes or selection on sperm haplotypes. However, progeny of high-treated sperm did not perform better than those of ambient-treated sperm when rearing temperatures were high. Overall, these findings offer little support for anticipatory hypothesis and suggest instead that beneficial paternal effects may be eroded when offspring develop under stressful conditions.,These data were collected from an experiment testing whether ejaculate-mediated paternal effects of temperature are adaptive for offspring, using the externally fertilizing mussel Mytilus galloprovincialis. Mussels were induced to spawn, and ejaculates from males (n = 34) were split into two aliquot; one aliquot was exposed to ambient temperature (19 °C) and the other to high temperature (24 °C). The aliquots were used to fertilise separate batches of pooled eggs (i.e., eggs pooled from mulriple females), and fertilization rates measured after 2 h. Each batch of eggs was then split into two aliquots that were exposed to different rearing temperatures over 48 h; again using ambient (19 °C) and high (24 °C) temperature treatments. After 48 h, the number of surviving offspring was counted, along with the proportion that were trocophore (first-stage) vs. veliger (second-stage) larvae and the portion that exhibited normal vs. abnormal morphology and swimming.,The dataset is ordered with variables in columns and samples in rows. Columns represent 'Block' (experimental day), 'Male' (unique ID for each male sperm donor), 'Sperm_temp' (sperm temperature treatment), 'Rearing_temp' (rearing temperature treatment), 'Sample' (unique ID for each sample), 'Trocophore' (number of trocophore larvae), 'Veliger' (number of veliger larvae), 'Abnormal' (number of larvae with abnormal morphology or swimming), 'Normal' (number of larvae with normal morphology and swimming), 'Total' (total number of surviving larvae at 48 h), 'Fert' (number of fertilized eggs out of a haphazard count of 100 in the original batch of eggs), and 'Fert_rate' (fertilization expressed as a proportion).,

近年来已有大量研究证据表明，父亲所处环境或其射精液可影响后代表型，即父本效应（paternal effects）。然而，学界对这类效应是否具有适应性仍知之甚少——而这一问题对诸多面临快速变化环境的物种而言，具有深远的研究意义。例如，部分观点提出父本效应可能是跨代可塑性（cross-generational plasticity）的来源，可使后代提前适应与亲本相似的环境条件（预期假说，anticipatory hypothesis）；与之相对，射精液介导的后代效应也可能仅是应激反应的非适应性副产物。本研究通过实验对这两种预测进行区分：将体外受精的贻贝（Mytilus galloprovincialis）的射精液分别暴露于常温（19℃）与高温（24℃）环境中，随后将后代分别置于与精子处理温度匹配或不匹配的环境中培育。研究发现，总体而言，经高温处理的精子可诱导后代产生更高的正常发育率，且在向第二期幼虫阶段的转换中成功率更高，这可能代表适应性表观遗传变化或精子单倍型的选择效应。但当后代在高温环境下培育时，经高温处理的精子所产生的后代并未比常温处理精子的后代表现更优。综上，本研究结果几乎不支持预期假说，反而表明当后代在应激环境下发育时，有益的父本效应可能会被抵消。
本数据集来自一项实验，旨在检验温度介导的射精液父本效应是否对贻贝（Mytilus galloprovincialis）的后代具有适应性。研究人员诱导贻贝产卵，将34尾雄性个体的射精液均分为两份：一份置于常温（19℃）环境，另一份置于高温（24℃）环境。随后利用两份处理后的射精液分别对混合的卵子批次（即从多尾雌性个体中收集的混合卵子）进行受精，并在受精2小时后测量受精率。每个卵子批次再被均分为两份，分别在常温（19℃）与高温（24℃）环境中培育48小时。培育48小时后，统计存活后代的数量，同时记录担轮幼虫（trocophore，第一期幼虫）与面盘幼虫（veliger，第二期幼虫）的占比，以及形态与游动状态正常与异常的幼虫比例。
本数据集以列代表变量、行代表样本的格式进行组织。各列分别为：Block（实验日期）、Male（每个雄性精子供体的唯一标识）、Sperm_temp（精子处理温度）、Rearing_temp（后代培育温度）、Sample（每个样本的唯一标识）、Trocophore（担轮幼虫数量）、Veliger（面盘幼虫数量）、Abnormal（形态或游动异常的幼虫数量）、Normal（形态与游动均正常的幼虫数量）、Total（48小时时存活幼虫的总数量）、Fert（原始卵子批次中随机计数100枚卵子时的受精卵子数）、Fert_rate（以比例表示的受精率）。