With rising ocean temperatures, extreme weather events such as marine heatwaves (MHWs) are increasing in frequency and duration, pushing marine life beyond their physiological limits. The potential to respond to extreme conditions through physiological acclimatization, and pass on resistance to the next generation, fundamentally depends on the capacity of an organism to cope within their thermal tolerance limits. To elucidate whether heat conditioning of parents could benefit offspring development, we exposed adult sea urchins (Heliocidaris erythrogramma) to ambient summer (23°C), moderate (25°C) or strong (26°C) MHW conditions for 10 days. Offspring were then reared at constant temperature along a thermal gradient (22–28°C) and development was tracked to the 14-day juvenile stage. Progeny from the MHW-conditioned adults developed through to metamorphosis faster than those of ambient conditioned parents, with most individuals from the moderate and strong heatwaves developing to the larval stage across all temperatures. In contrast, the majority of offspring from the control summer temperature died before metamorphosis at temperatures above 25°C (moderate MHW). Juveniles produced from the strong MHW-conditioned adults were also larger across all temperatures, with the largest juveniles in the 26°C treatment. In contrast, the smallest juveniles were from control (current-day summer) parents (and reared at 22 and 25°C). Surprisingly, initial survival was higher in the progeny of MHW exposed parents, even at temperatures hotter than predicted MHWs (28°C). Importantly, however, there was substantial mortality of juveniles from the strong MHW parents by day 14. Therefore, while carryover effects of parental conditioning to MHWs resulted in faster growing, larger progeny, this benefit will only persist beyond the more sensitive juvenile stage and enhance survival if conditions return promptly to normal seasonal temperatures within current thermal tolerance limits.

中文翻译：

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活得快死得早：暴露在热浪中的成年海胆对下一代发育的遗留影响

随着海洋温度升高，海洋热浪 (MHW) 等极端天气事件的频率和持续时间都在增加，从而使海洋生物超出其生理极限。通过生理适应来应对极端条件并将抵抗力传递给下一代的潜力，从根本上取决于生物体在其热耐受限度内应对的能力。为了阐明父母的热调节是否有利于后代发育，我们暴露了成年海胆（Heliocidaris erythrogramma) 环境夏季 (23°C)、中等 (25°C) 或强 (26°C) MHW 条件 10 天。然后沿着热梯度 (22–28°C) 在恒定温度下饲养后代，并追踪发育至 14 天的幼体阶段。MHW 条件成虫的后代比环境条件父母的后代更快地发育到变态，大多数个体从中等和强烈的热浪发展到所有温度的幼虫阶段。相比之下，控制夏季温度的大多数后代在温度高于 25°C（中等 MHW）的变态前死亡。由强 MHW 条件成虫生产的幼鱼在所有温度下也更大，在 26°C 处理中最大的幼鱼。相比之下，最小的幼鱼来自对照（当前夏季）父母（并在 22 和 25°C 下饲养）。令人惊讶的是，即使在比预测的 MHW (28°C) 更高的温度下，暴露于 MHW 的父母的后代的初始存活率更高。然而，重要的是，到第 14 天，强 MHW 父母的幼鱼死亡率很高。因此，虽然父母条件对 MHW 的遗留影响导致后代生长更快、更大，但这种好处只会持续到更敏感的幼年期之后并增强如果条件迅速恢复到当前热耐受限度内的正常季节性温度，则生存。