Marine heatwaves (MHWs) are projected to increase in intensity and frequency over the coming decades, and it is imperative to assess the adaptive capacity of marine organisms to these extreme temperature events. Given the nature of MHWs to last days to weeks in a region, these events may have overarching impacts on phenological events like reproduction and development. Here, the role of adult thermal history and transgenerational plasticity may be an important pathway by which MHWs are transduced to impact community structure. In this study, we sought to explore the effects of paternal thermal history in the purple urchin, Strongylocentrotus purpuratus, on a crucial aspect of reproduction, fertilization. Using ecologically relevant temperatures representative of both MHW events that occurred in 2014–2020 and non-MHW temperatures in our region of the California Large Marine Ecosystem, we conditioned male S. purpuratus for 28 days to either a high, MHW or a low, non-MHW temperature. Following the temperature acclimation of adults, sperm performance was tested for individual males by conducting fertilization success trials at varying temperatures and sperm concentrations. While sperm appeared robust to elevated temperature during fertilization, sperm produced by high-temperature-acclimated males had overall diminished performance as compared to those acclimated to non-MHW temperatures. These results suggest MHW events will have a negative impact on fertilization in situ for S. purpuratus populations. Furthermore, these results highlight the importance of considering both male and female environmental history in projections of reproduction under climate change scenarios.

预计未来几十年海洋热浪 (MHW) 的强度和频率将增加，因此必须评估海洋生物对这些极端温度事件的适应能力。鉴于 MHW 在一个地区持续数天到数周的性质，这些事件可能对繁殖和发育等物候事件产生总体影响。在这里，成体热史和跨代可塑性的作用可能是 MHW 被转导影响群落结构的重要途径。在这项研究中，我们试图探索父本热史对紫海胆Strongylocentrotus purpuratus 的影响，在繁殖的一个关键方面，受精。使用代表 2014-2020 年发生的 MHW 事件和加州大型海洋生态系统地区的非 MHW 温度的生态相关温度，我们调节了雄性紫癜保持 28 天，达到高 MHW 或低非 MHW 温度。在成人适应温度后，通过在不同温度和精子浓度下进行受精成功试验来测试个体男性的精子性能。虽然精子在受精过程中对升高的温度似乎很健壮，但与适应非 MHW 温度的精子相比，高温驯化的雄性产生的精子的性能总体下降。这些结果表明 MHW 事件将对S. purpuratus种群的原位受精产生负面影响。此外，这些结果强调了在气候变化情景下的生殖预测中考虑男性和女性环境历史的重要性。