Altshuler Douglas L, Dudley Robert
Section of Integrative Biology, University of Texas at Austin, Austin, TX 78712, USA.
J Exp Biol. 2002 Aug;205(Pt 16):2325-36. doi: 10.1242/jeb.205.16.2325.
The hovering ability, rapidity of maneuvers and upregulated aerobic capacity of hummingbirds have long attracted the interest of flight biologists. The range of intra- and interspecific variation in flight performance among hummingbirds, however, is equally impressive. A dominant theme in hummingbird evolution is progressive invasion of higher-elevation habitats. Hypobaric challenge is met behaviorally through compensatory changes in wingbeat kinematics, particularly in stroke amplitude. Over evolutionary time scales, montane colonization is associated with increases in body mass and relative wing area. Hovering ability has been well-studied in several North American hummingbird taxa, yet the broad range of interspecific variation in hummingbird axial and appendicular anatomy remains to be assessed mechanistically. Such varied features as tail length, molt condition and substantial weight change due to lipid-loading can dramatically alter various features of the flight envelope. Compared with our present knowledge of hovering performance in hummingbirds, the mechanics of forward flight and maneuvers is not well understood. Relationships among flight-related morphology, competitive ability and foraging behavior have been the focus of numerous studies on tropical and temperate hummingbirds. Ecologists have hypothesized that the primary selective agents on hummingbird flight-related morphology are the behaviors involved in floral nectar consumption. However, flight behaviors involved in foraging for insects may also influence the evolution of wing size and shape. Several comparisons of hummingbird communities across elevational gradients suggest that foraging strategies and competitive interactions within and among species vary systematically across elevations as the costs of flight change with body size and wing shape.
蜂鸟的悬停能力、动作敏捷性以及有氧能力的上调长期以来一直吸引着飞行生物学家的关注。然而，蜂鸟种内和种间飞行性能的变化范围同样令人印象深刻。蜂鸟进化的一个主要趋势是对高海拔栖息地的逐步入侵。通过翼拍运动学的补偿性变化，特别是冲程幅度的变化，行为上可以应对低压挑战。在进化时间尺度上，山地定居与体重和相对翼面积的增加有关。在几种北美蜂鸟分类群中，悬停能力已经得到了充分研究，但蜂鸟轴向和附属解剖结构种间差异的广泛范围仍有待从机制上进行评估。诸如尾长、换羽状况以及因脂质负载导致的体重显著变化等各种特征，都可能极大地改变飞行包线的各种特征。与我们目前对蜂鸟悬停性能的了解相比，向前飞行和机动的力学原理还没有得到很好的理解。飞行相关形态、竞争能力和觅食行为之间的关系一直是众多关于热带和温带蜂鸟研究的重点。生态学家推测，对蜂鸟飞行相关形态的主要选择因素是花蜜摄取所涉及的行为。然而，捕食昆虫所涉及的飞行行为也可能影响翅膀大小和形状的进化。对不同海拔梯度的蜂鸟群落进行的几次比较表明，随着飞行成本随体型和翅膀形状而变化，物种内和物种间的觅食策略和竞争相互作用会随着海拔高度而系统地变化。
