Repeated evolution of drag reduction at the air-water interface in diving kingfishers
Repeated evolution of drag reduction at the air-water interface in diving kingfishers
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DOI：
10.1098/rsif.2019.0125
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发表时间：
2019-05-01
影响因子：
3.9
通讯作者：
Falkingham, P. L.
中科院分区：
文献类型：
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作者：
Crandell, K. E.;Howe, R. O.;Falkingham, P. L.
食鱼鸟类有一套独特的适应水下觅食的方法。空中鸟类用来捕鱼的一种方法是俯冲，其中鸟类从高处俯冲以克服水中的阻力和浮力。翠鸟是一个著名的分支，包含陆地觅食和跳水物种，使我们能够测试在进化背景下觅食公会之间的形态和性能差异。潜水物种在背腹和矢状面有较窄的法案和较长的法案（尺寸校正数据，n = 71种，p，0.01的所有）。尽管这些差异受到遗传学的混淆（背腹侧p = 0.26和长度p = 0.14的遗传学校正的ANOVA），但矢状面中的喙宽仍然存在统计学差异（p < 0.001）。我们研究了喙形态对俯冲性能的影响，通过物理模拟潜水与三维打印模型的喙加上加速度计，并通过计算流体动力学（CFD）。从物理模拟潜水的法案模型，潜水物种有较低的峰值减速，因此更快地进入水中，比陆地和混合觅食物种（ANOVA p = 0.002），这一结果仍然不受遗传学（遗传学校正ANOVA p = 0.05）。CFD分析证实了三种代表性物种的这些趋势，并表明喙和头部之间的形态是减少水生物种阻力的关键部位。
Piscivorous birds have a unique suite of adaptations to forage under the water. One method aerial birds use to catch fish is the plunge dive, wherein birds dive from a height to overcome drag and buoyancy in the water. The kingfishers are a well-known clade that contains both terrestrially foraging and plunge-diving species, allowing us to test for morphological and performance differences between foraging guilds in an evolutionary context. Diving species have narrower bills in the dorsoventral and sagittal plane and longer bills (size-corrected data, n = 71 species, p, 0.01 for all). Although these differences are confounded by phylogeny (phylogenetically corrected ANOVA for dorsoventral p = 0.26 and length p = 0.14), beak width in the sagittal plane remains statistically different (p < 0.001). We examined the effects of beak morphology on plunge performance by physically simulating dives with three-dimensional printed models of beaks coupled with an accelerometer, and through computational fluid dynamics (CFD). From physically simulated dives of bill models, diving species have lower peak decelerations, and thus enter the water more quickly, than terrestrial and mixed-foraging species (ANOVA p = 0.002), and this result remains unaffected by phylogeny (phylogenetically corrected ANOVA p = 0.05). CFD analyses confirm these trends in three representative species and indicate that the morphology between the beak and head is a key site for reducing drag in aquatic species.