More than 50% of all animal species are insects that undergo complete metamorphosis. The key innovation of these holometabolous insects is a pupal stage between the larva and adult when most structures are completely rebuilt. Why this extreme lifestyle evolved is unclear. Here, we test the hypothesis that a trade-off between growth and differentiation explains the evolution of this novelty. Using a comparative approach, we find that holometabolous insects grow much faster than hemimetabolous insects. Using a theoretical model, we then show how holometaboly evolves under a growth-differentiation trade-off and identify conditions under which such temporal decoupling of growth and differentiation is favored. Our work supports the notion that the holometabolous life history evolved to remove developmental constraints on fast growth, primarily under high mortality.

中文翻译：

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昆虫的快速生长和完全变态的进化


超过 50% 的动物物种是经历完全变态的昆虫。这些全变态昆虫的关键创新是幼虫和成虫之间的蛹阶段，此时大多数结构都完全重建。为什么会形成这种极端的生活方式尚不清楚。在这里，我们检验了这样一个假设：增长和分化之间的权衡解释了这种新颖性的演变。通过比较方法，我们发现全变态昆虫比半变态昆虫生长得快得多。然后，我们使用理论模型展示了全变态如何在生长-分化权衡下进化，并确定了有利于生长和分化的这种时间解耦的条件。我们的工作支持这样的观点，即全变态生命史的进化是为了消除快速生长的发育限制，主要是在高死亡率的情况下。