Morphological values of three traits of adult male hummingbirds.

We compiled measurements of three traits in adult males: body mass, wing chord (i.e., closed wing-length), and length of exposed culmen (Graham et al. 2012). The three traits represent important morphological interfaces for hummingbird flight, physiology, feeding and behavior. Body mass is related to thermoregulatory adaptations to high elevation habitats, as well as aggressive interactions among territorial species (Altshuler and Dudley 2002; González-Gómez et al. 2011a; González-Gómez et al. 2011b). Wing chord is a component of hovering flight, which becomes more difficult at high elevations due to lower air density (Altshuler et al. 2004; Stiles et al. 2005). Bill length is associated with resource use, foraging efficiency, and the matching between bill lengths and corolla lengths in hummingbird pollinated plants (Feinsinger et al. 1979; Smith et al. 1996; Temeles et al. 2002). These three traits show a predicted trait environment-relationship when all species in an assemblage are considered: body mass increases with elevation, wing chord increases with elevation and bill length decreases with elevation (high elevation flowers have short corollas; (Stiles 2008)). All three traits can be well described by a Brownian motion model of trait evolution, indicating phylogenetic signal (Blombergs K ~ 1 for all traits; Graham et al. 2012).

我们收集了成年雄性个体的三项形态性状测量数据：体重、翼弦（wing chord，即闭合翅长）以及裸露嘴峰（exposed culmen）长度，相关数据源自Graham等人2012年的研究。该三项性状均为关联蜂鸟飞行、生理机能、取食行为与活动模式的关键形态学关联特征。体重与高海拔生境下的体温调节适应以及领地性物种间的攻击性互作紧密相关（Altshuler与Dudley 2002；González-Gómez等人2011a；González-Gómez等人2011b）。翼弦是悬停飞行的核心构成参数，由于高海拔地区空气密度更低，悬停飞行的难度显著升高（Altshuler等人2004；Stiles等人2005）。嘴峰长度与资源利用策略、取食效率以及蜂鸟传粉植物的花筒长度与嘴峰长度的匹配关系紧密相关（Feinsinger等人1979；Smith等人1996；Temeles等人2002）。当整合某一蜂鸟群落内所有物种的数据时，三项性状均呈现出预期的性状-环境关联规律：体重随海拔升高而增加，翼弦随海拔升高而增大，而嘴峰长度则随海拔升高而缩短——这一规律的成因是高海拔生境的植物花筒长度更短（Stiles 2008）。三项性状的演化过程均可通过布朗运动模型（Brownian motion model）较好地拟合，表明其存在系统发育信号（phylogenetic signal）（所有性状的Blomberg's K值均约为1；Graham等人2012）。