Coral bleaching, the stress‐induced breakdown of coral‐algal symbiosis, threatens reefs globally. Paradoxically, despite adverse fitness effects, corals bleach annually, even outside of abnormal temperatures. This generally occurs shortly after the once‐per‐year mass coral spawning. Here, we propose a hypothesis linking annual coral bleaching and the transmission of symbionts to the next generation of coral hosts. We developed a dynamic model with two symbiont growth strategies, and found that high sexual recruitment and low adult coral survivorship and growth favour bleaching susceptibility, while the reverse promotes bleaching resilience. Otherwise, unexplained trends in the Indo‐Pacific align with our hypothesis, where reefs and coral taxa exhibiting higher recruitment are more bleaching susceptible. The results from our model caution against interpreting potential shifts towards more bleaching‐resistant symbionts as evidence of climate adaptation—we predict such a shift could also occur in declining systems experiencing low recruitment rates, a common scenario on today's reefs.

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我应该走还是留？从共生体的角度来看珊瑚白化

珊瑚白化是压力引起的珊瑚藻共生破坏，威胁着全球的珊瑚礁。矛盾的是，尽管对健康产生不利影响，珊瑚每年都会白化，即使在异常温度之外也是如此。这通常发生在每年一次的珊瑚大规模产卵后不久。在这里，我们提出了一个假设，将每年的珊瑚白化与共生体向下一代珊瑚宿主的传播联系起来。我们开发了一个具有两种共生生长策略的动态模型，发现高性招募和低成年珊瑚存活率和生长有利于白化敏感性，而相反则促进白化恢复力。否则，印度太平洋地区无法解释的趋势与我们的假设相符，即表现出较高补充量的珊瑚礁和珊瑚类群更容易发生白化。我们的模型结果警告不要将向更耐白化共生体的潜在转变解释为气候适应的证据——我们预测这种转变也可能发生在经历低补充率的衰退系统中，这是当今珊瑚礁的常见情况。