Experimental studies of the use of visual and olfactory cues by flower-visiting animals can shed light on the evolution of floral signalling traits. We examined the functional significance of floral traits in Clivia miniata (Amaryllidaceae). This forest lily with large orange trumpet-shaped flowers is pollinated mainly by swallowtail butterflies and belongs to a lineage with ancestral bird pollination. We used C. miniata flowers varying in colour, orientation and scent, and arrays of artificial flowers varying in colour, pattern, orientation, size, shape, and scent to assess foraging preferences of the butterflies that pollinate C. miniata. Butterflies preferred orange over yellow colour morphs of C. miniata and preferred red and orange model flowers over yellow ones. Orange models with a central yellow target ‘nectar guide’ were favoured over plain orange models. Butterflies also favoured large over small model flowers and preferred to alight on upward-facing flowers. Addition of scent compounds emitted by C. miniata flowers increased butterfly visitation to model and natural flowers. These results identify the importance of particular combinations of visual and olfactory signals for attraction of swallowtail butterflies and shed light on the floral modifications associated with a shift from bird to butterfly pollination.

访花动物对视觉和嗅觉线索的使用的实验研究可以揭示花卉信号特性的演变。我们检查了君子兰（Amaryllidaceae）中的花卉性状的功能意义。这种森林百合具有大的橙色喇叭形花，主要由燕尾蝴蝶授粉，属于祖先鸟授粉的血统。我们使用C.君子兰花颜色，取向和气味变化，和人造花在颜色，图案，取向，尺寸，形状，和气味改变阵列来评估觅食授粉蝴蝶的偏好C.君子兰。过的黄色变种蝴蝶优选橙C.君子兰并且比黄色的花朵更喜欢红色和橙色的模特花朵。具有中心黄色目标“花蜜引导”的橙色模型优于纯橙色模型。蝴蝶还偏爱大型花朵而不是小型花朵，并且偏爱落在朝上的花朵上。小花C. miniata花散发出的香气化合物增加了蝴蝶对模型花和天然花的访问。这些结果表明，视觉和嗅觉信号的特定组合对于燕尾蝶的吸引和阐明从鸟授粉到蝶粉授粉相关的花卉修饰的重要性。