Animals have encountered novel foods at points throughout history, due to factors such as range expansions and niche shifts driven by competition. One of the first challenges presented by novel foods is how to eat them. Mouthpart morphology is thus critical during the process of host shifts. Developmental plasticity in mouthparts is one potential mechanism that may allow animals to tolerate new foods and eventually to thrive upon them. Here, we investigated the extent to which insect mouthparts from two geographically distant populations can converge in morphology when feeding on common resources. We conducted a common garden/reciprocal transplant experiment using two populations of the cactus bug, Narnia femorata, that differ in mouthpart length. This insect uses straw-like mouthparts (hereafter "beak") to get through the cactus fruit wall to reach the pulp inside. Our experimental results revealed clear developmental plasticity in beak length. Insects from both populations grew longer beaks when they fed on the cactus fruit with the thicker walls, and they grew shorter beaks when they fed on the cactus fruit with the thinner walls. Thus, insects from distant populations exhibited immediate developmental responses to a new food, and in the predicted directions. These results suggest that some fauna may be able to respond more rapidly than predicted when they encounter novel plants.

中文翻译：

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半翅目口器对物理障碍的快速和适应性反应的证据

由于范围扩大和竞争驱动的生态位转变等因素，动物在历史上的各个时期都遇到过新食物。新食物带来的首要挑战之一是如何食用。因此，口器形态在宿主转移过程中至关重要。口器的发育可塑性是一种潜在机制，可以让动物耐受新食物并最终在这些食物上茁壮成长。在这里，我们调查了来自两个地理上遥远种群的昆虫口器在以共同资源为食时在形态上会聚的程度。我们使用口器长度不同的两个仙人掌虫种群 Narnia femorata 进行了一个普通的花园/相互移植实验。这种昆虫使用稻草状的口器（以下简称“喙”）) 穿过仙人掌果壁到达里面的果肉。我们的实验结果揭示了喙长度的明显发育可塑性。两个种群的昆虫在以壁较厚的仙人掌果实为食时都长出较长的喙，而在以壁较薄的仙人掌果实为食时，它们的喙部较短。因此，来自遥远种群的昆虫表现出对新食物的直接发育反应，并朝着预测的方向发展。这些结果表明，当某些动物遇到新植物时，它们的反应速度可能比预期的要快。当它们以壁较薄的仙人掌果实为食时，它们的喙会变短。因此，来自遥远种群的昆虫表现出对新食物的直接发育反应，并朝着预测的方向发展。这些结果表明，当某些动物遇到新植物时，它们的反应速度可能比预期的要快。当它们以壁较薄的仙人掌果实为食时，它们的喙会变短。因此，来自遥远种群的昆虫表现出对新食物的直接发育反应，并朝着预测的方向发展。这些结果表明，当某些动物遇到新植物时，它们的反应速度可能比预期的要快。