Intraspecific morphological variation fundamentally influences individual resource exploitation. In plant–pollinator systems, variation in floral morphologies and pollinator mouthparts may affect pollinators' resource use. This relationship has frequently been studied across species, but hardly ever at the intraspecific level in natural circumstances. We studied flower visits of clouded Apollo butterflies, Parnassius mnemosyne. (1) We investigated whether proboscis (mouthpart) length variability influenced individual nectar plant choice within a single population. We hypothesized that flower depths would constrain butterflies’ flower visits via their proboscis lengths. (2) We studied whether individual proboscis length constrained feeding on the sticky catchfly, Silene viscaria, a species with ample nectar and the deepest corolla among the plants visited. We hypothesized that individuals observed visiting S. viscaria had longer proboscides than those not observed on this nectar source. We captured clouded Apollos, then measured proboscis length. We surveyed the population daily, identified marked individuals and recorded feeding on nectar plant species. We compared proboscis length to the flower depth of the six most-visited nectar plants and investigated whether individual visits on flowering plants were related to proboscis length. We found large intrapopulation variation in proboscis length, and high intra- and interspecific variation in flower depth of the six nectar plants. Flower depth of S. viscaria largely overlapped with proboscis length, while the other five plants had shorter flowers. Individuals with longer proboscides visited S. viscaria flowers more often than those with short proboscides. These results indicate the importance of morphological variation in the interaction between plants and pollinators. We provide the first evidence that individual variation in mouthpart length affects lepidopteran foraging in natural circumstances. We suggest that interactions between species in plant–pollinator systems are partially based on individually different continuous traits, rather than on well-defined discrete traits of different taxa as implied by the pollination syndrome hypothesis.

中文翻译：

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所有的蝴蝶都是平等的吗？种群明智的长鼻长度变化预测蝴蝶的花朵选择

种内形态变异从根本上影响个体资源开发。在植物传粉系统中，花的形态和传粉者口器的变化可能会影响传粉者的资源利用。这种关系经常被跨物种研究，但在自然环境中几乎没有在种内水平上进行过研究。我们研究了云雾缭绕的阿波罗蝴蝶 Parnassius mnemosyne 的访花。(1) 我们调查了长鼻（口器）长度变异是否影响单个种群内的个体花蜜植物选择。我们假设花的深度会通过它们的长鼻限制蝴蝶的花访问。(2) 我们研究了个体长鼻是否限制了捕食粘蝇、Silene viscaria、一种花蜜充足、花冠最深的植物。我们假设观察到访问 S. viscaria 的个体比在该花蜜源上未观察到的个体具有更长的长鼻。我们捕获了云雾缭绕的阿波罗，然后测量了长鼻长度。我们每天对种群进行调查，确定标记个体并记录对花蜜植物物种的摄食。我们将长鼻长度与六种访问量最大的花蜜植物的花深进行了比较，并调查了开花植物的个体访问是否与长鼻长度有关。我们发现六种花蜜植物的长鼻长度存在较大的种群内变异，以及花深的高种内和种间变异。S. viscaria 的花深与长鼻长度基本重叠，而其他五种植物的花较短。长鼻的个体比长鼻的个体更频繁地访问 S. viscaria 花。这些结果表明形态变异在植物和传粉者之间的相互作用中的重要性。我们提供了第一个证据，表明口器长度的个体差异会影响自然环境中鳞翅目昆虫的觅食。我们建议植物-传粉系统中物种之间的相互作用部分基于个体不同的连续性状，而不是传粉综合征假说所暗示的不同分类群的明确定义的离散性状。我们提供了第一个证据，表明口器长度的个体差异会影响自然环境中鳞翅目昆虫的觅食。我们建议植物-传粉系统中物种之间的相互作用部分基于个体不同的连续性状，而不是传粉综合征假说所暗示的不同分类群的明确定义的离散性状。我们提供了第一个证据，表明口器长度的个体差异会影响自然环境中鳞翅目昆虫的觅食。我们建议植物-传粉系统中物种之间的相互作用部分基于个体不同的连续性状，而不是传粉综合征假说所暗示的不同分类群的明确定义的离散性状。