Population dynamics of organisms are shaped by the variation in phenotypic traits, often expressed even among individuals from the same cohort. For example, individual variation in the timing of ontogenetic shifts in diet and/or habitat greatly influences subsequent growth and survival of some organisms, with critical effects on population dynamics. Few studies of natural systems have, however, demonstrated that marked phenotypic variation in growth rates or body size among individuals within a modelled cohort is linked to dietary shifts and food availability. Population irruptions of the crown-of-thorns starfish are one of the foremost contributors to the global degradation of coral reefs, but causes of irruptions have been debated for decades. Here we demonstrate, based on extensive field sampling of juvenile starfish (n = 3532), that marked variation in body size among juvenile starfish is linked to an ontogenetic diet shift from coralline algae to coral. This transition in diet leads to exponential growth in juveniles and is essential for individuals to reach maturity. Because smaller individuals experience higher mortality and growth is stunted on an algal diet, the ontogenetic shift to corallivory enhances individual fitness and replenishment success. Our findings suggest that the availability of coral prey facilitates early ontogenetic diet shifts and may be fundamental in initiating population irruptions.

中文翻译：

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与个体遗传饮食变化相关的幼年棘冠海星的对比大小和命运

生物体的种群动态受表型特征的变化影响，甚至在同一队列的个体中也经常表现出来。例如，饮食和/或栖息地个体遗传变化时间的个体差异极大地影响了某些生物的后续生长和存活，对种群动态产生了关键影响。然而，很少有关于自然系统的研究表明，模型队列中个体的生长率或体型的显着表型变化与饮食变化和食物供应有关。棘冠海星的种群数量激增是全球珊瑚礁退化的最重要原因之一，但几十年来，人们一直在争论种群数量激增的原因。在这里，我们证明，基于对幼年海星（n = 3532）的广泛实地采样，幼年海星体型的显着差异与个体遗传饮食从珊瑚藻转变为珊瑚有关。这种饮食转变导致幼鱼呈指数增长，对个体达到成熟至关重要。由于体型较小的个体死亡率较高，而且藻类饮食会阻碍生长，因此个体遗传向珊瑚食的转变增强了个体的健康和补充成功。我们的研究结果表明，珊瑚猎物的可用性促进了早期个体遗传饮食的转变，并且可能是引发种群爆发的基础。由于体型较小的个体死亡率较高，而且藻类饮食会阻碍生长，因此个体遗传向珊瑚食的转变增强了个体的健康和补充成功。我们的研究结果表明，珊瑚猎物的可用性促进了早期个体遗传饮食的转变，并且可能是引发种群爆发的基础。由于体型较小的个体死亡率较高，而且藻类饮食会阻碍生长，因此个体遗传向珊瑚食的转变增强了个体的健康和补充成功。我们的研究结果表明，珊瑚猎物的可用性促进了早期个体遗传饮食的转变，并且可能是引发种群爆发的基础。