When hatchlings outperform adults: locomotor development in Australian brush turkeys (Alectura lathami, Galliformes)
When hatchlings outperform adults: locomotor development in Australian brush turkeys (Alectura lathami, Galliformes)
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DOI：
10.1098/rspb.2010.1984
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发表时间：
2011-06-07
影响因子：
4.7
通讯作者：
Jackson, Brandon E.
中科院分区：
文献类型：
--
作者：
Dial, Kenneth P.;Jackson, Brandon E.
在鸡形目中，大足类（刷火鸡，malleefowl，scrubfowl）表现出独特的父母照顾和生长形式。雏鸟孵化后没有得到父母的照顾，表现出所有现存鸟类中最夸张的早熟发育，孵化时前肢发育完全，能够飞行。而不是飞到安全，幼鸟优先采用翅膀辅助倾斜运行。新孵化的澳大利亚刷火鸡（Alectura lathami）非常精通谈判所有纹理倾斜的表面，可以皮瓣步行超过垂直倾斜。然而，随着灌木火鸡的成长，它们依赖前肢的运动能力下降。在试图阐明如何孵化执行这么好，我们分析了后肢的力量和前肢运动学。我们测量了动物在整个生长范围（110-2000 g）内的地面反作用力（GRF），因为它们爬上了一个装有测力板的倾斜坡道。这些数据进行了比较与一个类似的数据集的一个chukar paradigm（Alecomarchukar），表现出典型的增长策略，大多数其他鸡形目，并表现出改善的倾斜性能，随着年龄的增长。灌丛火鸡在倾斜奔跑中的个体发育性下降伴随着在陡峭角度下的牵引力丧失、GRF降低和翼载增加。我们假设，澳大利亚刷火鸡，与其他鸡形目，从前肢为主的年轻，利用可变的地形（e。G.土墩巢、巨石、灌木丛、悬崖、灌木丛和树木）转变为后肢为主的成年动物，依赖于大小和奔跑速度以避免被捕食。
Within Galliformes, megapods (brush turkey, malleefowl, scrubfowl) exhibit unique forms of parental care and growth. Hatchlings receive no post-hatching parental care and exhibit the most exaggerated precocial development of all extant birds, hatching with fully developed, flight-capable forelimbs. Rather than flying up to safety, young birds preferentially employ wing-assisted incline running. Newly hatched Australian brush turkeys (Alectura lathami) are extraordinarily proficient at negotiating all textured inclined surfaces and can flap-walk up inclines exceeding the vertical. Yet, as brush turkeys grow, their forelimb-dependent locomotor performance declines. In an attempt to elucidate how hatchlings perform so well, we analysed hindlimb forces and forelimb kinematics. We measured ground reaction forces (GRFs) for animals spanning the entire growth range (110-2000 g) as they ascended a variably positioned inclined ramp that housed a forceplate. These data are compared with a similar dataset for a chukar partridge (Alectoris chukar) that exhibit a growth strategy typical of most other Galliformes and that demonstrate improved incline performance with increasing age. The brush turkeys' ontogenetic decline in incline running performance is accompanied by loss of traction at steep angles, reduced GRFs and increased wing-loading. We hypothesize that Australian brush turkeys, in contrast to other Galliformes, develop from forelimb-dominated young that exploit a variable terrain (e. g. mound nests, boulders, embankments, cliffs, bushes and trees) into hindlimb-dominated adults dependent on size and running speed to avoid predation.