Flight performance and competitive displacement of hummingbirds across elevational gradients
Flight performance and competitive displacement of hummingbirds across elevational gradients
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DOI：
10.1086/498622
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发表时间：
2006-02-01
影响因子：
2.9
通讯作者：
Altshuler, DL
中科院分区：
文献类型：
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作者：
Altshuler, DL
蜂鸟具有令人印象深刻的飞行能力和竞争性的空中竞赛，是应用机械方法研究社区结构的理想候选人。由于飞行成本受到非生物因素的影响，这些因素随海拔高度系统地变化，海拔梯度为蜂鸟飞行生态学提供了自然实验。以前的尝试依赖于翼盘载荷（WDL）作为飞行性能的形态替代，但最近的分析表明，这个变量并不影响领土行为或竞争能力。相比之下，空气动力学功率可以从性能的直接测量中得出，并且像WDL一样，在海拔高度上下降。在这里，我证明了一个不同的社区安第斯蜂鸟，爆发空气动力学的权力与领土行为。在科罗拉多，我沿着沿着第二个海拔梯度，测试了两只领地蜂鸟的空气动力和竞争能力的相关变化。这一行为分析表明，短翅Selasphorus rufus男性占主导地位的长翅Selasphorus platycercus男性在低海拔地区，但在较高的海拔地区的角色是颠倒的。有几条证据支持这一假设，即爆发而不是持续的空气动力学性能介导的高海拔竞争能力。爆发力的最小值可能是成功竞争所必需的，但当所有竞争者都有足够的肌肉力量时，其他机动性特征变得重要，如在低海拔地区。
Hummingbirds, with their impressive flight ability and competitive aerial contests, make ideal candidates for applying a mechanistic approach to studying community structure. Because flight costs are influenced by abiotic factors that change systematically with altitude, elevational gradients provide natural experiments for hummingbird flight ecology. Prior attempts relied on wing disc loading (WDL) as a morphological surrogate for flight performance, but recent analyses indicate this variable does not influence either territorial behavior or competitive ability. Aerodynamic power, by contrast, can be derived from direct measurements of performance and, like WDL, declines across elevations. Here, I demonstrate for a diverse community of Andean hummingbirds that burst aerodynamic power is associated with territorial behavior. Along a second elevational gradient in Colorado, I tested for correlated changes in aerodynamic power and competitive ability in two territorial hummingbirds. This behavioral analysis revealed that short-winged Selasphorus rufus males are dominant over long-winged Selasphorus platycercus males at low elevations but that the roles are reversed at higher elevations. Several lines of evidence support the hypothesis that the burst rather than sustained aerodynamic performance mediates competitive ability at high elevation. A minimum value for burst power may be required for successful competition, but other maneuverability features gain importance when all competitors have sufficient muscle power, as occurs at low elevations.