2026-04-13 カリフォルニア大学バークレー校（UCB）
CT scans reveal striking bill and tongue differences between the Olive Sunbird (Cyanomitra olivacea, top) and Anna’s Hummingbird (Calypte anna, bottom). Cross sections at several places along the bill show that, from base to tip, the sunbird tongue shifts from a U-shaped trough to a closed tube, while the hummingbird tongue transforms from two solid rods into twin hollow tubes. The U-shaped base of the sunbird tongue interacts with the upper bill to create the suction the birds use to sip nectar from flowers.Cynthia Wang-Claypool/UC Berkeley
＜関連情報＞
- https://news.berkeley.edu/2026/04/13/sunbirds-suck-scientists-find-hummingbirds-dont/
- https://www.cell.com/current-biology/abstract/S0960-9822(26)00254-X
- https://academic.oup.com/iob/article/1/1/oby006/5267482?login=false
タイヨウチョウにおける舌内吸引によって明らかになった、多様な蜜摂取メカニズム Divergent nectar-feeding mechanisms evidenced by intralingual suction in sunbirds
David Cuban ∙ Cynthia Y. Wang-Claypool ∙ Yohanna Yohanna ∙ … ∙ Fabian Brau ∙ Steven D. Johnson ∙ Alejandro Rico-Guevara
Current Biology Published:March 27, 2026
DOI:https://doi.org/10.1016/j.cub.2026.02.067
Highlights
- Sunbirds use intralingual suction when feeding from floral nectar
- microCT, high-speed video, and fluid dynamics modeling reveal the novel mechanism
- This feeding mechanism shows biomechanical divergence despite niche convergence
Summary
Nectarivory has independently evolved many times among birds, yet little is known about the diversity of feeding mechanisms that enable specialized taxa to efficiently collect this energy-rich resource. Multiple avian groups have converged on evolving elongated bills and tube-like tongues adapted for nectar extraction. Old World sunbirds (family Nectariniidae) stand out as having the greatest degree of convergence in bill and tongue morphology with the well-studied and highly specialized New World hummingbirds (family Trochilidae), which fill their tongues via fluid trapping and expansive filling. However, using museum specimens, high-speed video, and fluid modeling, we show that sunbirds use a unique drinking mechanism not found in any other animal: intralingual suction. Using tube-like tongues, sunbirds are able to move nectar from flowers to their mouths by generating a pressure differential along the length of the tongue, a remarkable feat for animals without lips or cheeks. We show how this feeding mechanism works and how it can be modeled mathematically. This discovery raises new questions for both vertebrate and invertebrate groups that feed on liquid food, and we anticipate that our results will be used to evaluate both food capture mechanisms and their efficiencies. For example, knowing the feeding mechanism allows the energy intake rate to be accurately predicted and tested, leading to reliable energy budget models and minimum requirements that, in turn, circumscribe more complex ecological interactions.
蜜の抽出メカニズムとハチドリのくちばしの形態におけるパラダイムシフト Shifting Paradigms in the Mechanics of Nectar Extraction and Hummingbird Bill Morphology
A Rico-Guevara ,M A Rubega ,K J Hurme ,R Dudley
Integrative Organismal Biology Published:02 January 2019
DOI:https://doi.org/10.1093/iob/oby006
Abstract
As functional morphologists, we aim to connect structures, mechanisms, and emergent higher-scale phenomena (e.g., behavior), with the ulterior motive of addressing evolutionary patterns. The fit between flowers and hummingbird bills has long been used as an example of impressive co-evolution, and hence hummingbirds’ foraging behavior and ecological associations have been the subject of intense study. To date, models of hummingbird foraging have been based on the almost two-centuries-old assumption that capillary rise loads nectar into hummingbird tongue grooves. Furthermore, the role of the bill in the drinking process has been overlooked, instead considering it as the mere vehicle with which to traverse the corolla and access the nectar chamber. As a scientific community, we have been making incorrect assumptions about the basic aspects of how hummingbirds extract nectar from flowers. In this article, we summarize recent advances on drinking biomechanics, morphological and ecological patterns, and selective forces involved in the shaping of the hummingbird feeding apparatus, and also address its modifications in a previously unexpected context, namely conspecific and heterospecific fighting. We explore questions such as: how do the mechanics of feeding define the limits and adaptive consequences of foraging behaviors? Which are the selective forces that drive bill and tongue shape, and associated sexually dimorphic traits? And finally, what are the proximate and ultimate causes of their foraging strategies, including exploitative and interference competition? Increasing our knowledge of morphology, mechanics, and diversity of hummingbird feeding structures will have implications for understanding the ecology and evolution of these remarkable animals.
