Department of Biology, University of Washington, Seattle, Washington, USA.
Burke Museum of Natural History and Culture, Seattle, Washington, USA.
J Morphol. 2022 Dec;283(12):1483-1504. doi: 10.1002/jmor.21513. Epub 2022 Oct 18.
Nectar-feeding birds provide an excellent system in which to examine form-function relationships over evolutionary time. There are many independent origins of nectarivory in birds, and nectar feeding is a lifestyle with many inherent biophysical constraints. We review the morphology and function of the feeding apparatus, the locomotor apparatus, and the digestive and renal systems across avian nectarivores with the goals of synthesizing available information and identifying the extent to which different aspects of anatomy have morphologically and functionally converged. In doing so, we have systematically tabulated the occurrence of putative adaptations to nectarivory across birds and created what is, to our knowledge, the first comprehensive summary of adaptations to nectarivory across body systems and taxa. We also provide the first phylogenetically informed estimate of the number of times nectarivory has evolved within Aves. Based on this synthesis of existing knowledge, we identify current knowledge gaps and provide suggestions for future research questions and methods of data collection that will increase our understanding of the distribution of adaptations across bodily systems and taxa, and the relationship between those adaptations and ecological and evolutionary factors. We hope that this synthesis will serve as a landmark for the current state of the field, prompting investigators to begin collecting new data and addressing questions that have heretofore been impossible to answer about the ecology, evolution, and functional morphology of avian nectarivory.
以鸟类为研究对象，探究其在进化过程中形态与功能的关系，花蜜鸟是一个极佳的范例。鸟类中存在许多独立起源的花蜜取食行为，且花蜜取食是一种具有诸多固有生物物理限制的生活方式。我们综述了鸟类花蜜取食者的取食器官、运动器官、消化和肾脏系统的形态和功能，旨在综合现有信息，并确定不同解剖结构在形态和功能上的趋同程度。在这一过程中，我们系统地整理了不同鸟类适应花蜜取食的特征，并首次全面总结了不同身体系统和分类单元中适应花蜜取食的特征。我们还提供了鸟类中花蜜取食进化次数的首次系统发育信息估算。基于对现有知识的综合，我们确定了当前的知识空白，并提出了未来研究问题和数据收集方法的建议，这将有助于我们更好地了解适应特征在不同身体系统和分类单元中的分布，以及这些适应特征与生态和进化因素之间的关系。我们希望这一综述能成为该领域当前状况的一个里程碑，促使研究人员开始收集新的数据，并解决迄今为止难以回答的有关鸟类花蜜取食的生态学、进化和功能形态学的问题。
