United in difference: on the divergence in floral preferences between Galápagos birds and insects

Dataset Sixteen morphological and nectar traits of 31 Galápagos plant species studied in the arid zone between March 2016 and April 2017. Study AbstractThe characteristic scarcity of insects on remote oceanic islands has driven non-flower specialized vertebrates to broaden their trophic niches and explore floral resources. From our previous studies in the Galápagos, we know that native insectivorous and frugivorous Galápagos birds visit a wide range of typical entomophilous flowers and can also act as effective pollinators. Here, we tested whether opportunistic Galápagos birds show any preference for specific floral traits, and if this preference differs from that of insects. Sixteen morphological and nectar traits of 31 Galápagos plant species were studied, as well as their visitation frequency by birds and insects. Non-metric multidimensional scaling (NMDS) was used to evaluate the dispersal of flower trait values along two main dimensions and measure the similarity between the plants visited mostly by birds versus those by insects. A NMDS of floral traits resulted in two species groups: i) larger, bell-shaped flowers with slight larger nectar volume, associated with high bird visitation rates; and ii) smaller, bowl-shaped flowers with lower nectar volume, associated with high insect visitation rates. Galápagos birds preferred species with floral traits intermediate between those of insect- and bat-pollination syndromes. This finding is coherent with the existence of a transitional or bet-hedging phenotype between insect and bird pollination and underscores the importance of coevolution and floral diversification in non-specialized plant-pollinator mutualisms.

数据集：本数据集涵盖2016年3月至2017年4月间在干旱带研究的31种加拉帕戈斯（Galápagos）植物的16项形态与花蜜性状。
研究摘要
偏远海洋岛屿上昆虫资源的典型匮乏，促使非特化访花脊椎动物拓展自身营养生态位，并探索花部资源。基于我们此前在加拉帕戈斯开展的研究，已知本地食虫、食果的加拉帕戈斯鸟类会造访多种典型虫媒花，同时可作为有效的传粉者。本研究旨在检验机会主义型加拉帕戈斯鸟类是否对特定花部性状存在偏好，且该偏好是否与昆虫的偏好存在差异。本研究对31种加拉帕戈斯植物的16项形态与花蜜性状，以及鸟类、昆虫对这些植物的造访频率进行了观测与分析。本研究采用非度量多维标度法（Non-metric Multidimensional Scaling, NMDS），评估花部性状值在两个主维度上的分布格局，并比较主要被鸟类造访与主要被昆虫造访的植物类群间的相似性。基于花部性状的非度量多维标度分析将供试植物划分为两个类群：① 花型较大、呈钟形、花蜜体积略高的类群，对应较高的鸟类造访频率；② 花型较小、呈碗形、花蜜体积较低的类群，对应较高的昆虫造访频率。加拉帕戈斯鸟类偏好花部性状介于虫媒传粉与蝠媒传粉综合征之间的植物类群。该发现与昆虫传粉与鸟类传粉之间存在过渡型或风险对冲表型的结论相符，同时凸显了协同进化与花部多样化在非特化植物-传粉者互利共生关系中的重要性。