Jumping mechanisms and performance of snow fleas (Mecoptera, Boreidae)
Jumping mechanisms and performance of snow fleas (Mecoptera, Boreidae)
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DOI：
10.1242/jeb.056689
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发表时间：
2011-07-01
影响因子：
2.8
通讯作者：
Burrows, Malcolm
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文献类型：
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作者：
Burrows, Malcolm
不会飞的雪蚤（雪蝎蝇，长翅目，Boreidae）在北方的冬季以成虫形式生活，经常在雪表面跳跃和行走。用高速摄影技术分析了它们的跳跃机理和性能。跳跃是由中间和后腿的同时运动推动的，这是由5000帧的图像速率所提供的0.2ms分辨率来判断的。s（-1）。雄性的中腿占体长的140%，后腿占187%，腿长比为1：1.3：1.7（前：中：后）。在准备跳跃时，将中腿和后腿在其髋关节处向前旋转，使中胸和后胸融合。跳跃的第一个推进运动是转子绕着髋关节旋转，由胸腔内的大的减压肌提供动力。加速时间为6.6ms，男性最快起跳速度为1 m·s（-1），需要能量1.1 μ J，输出功率0.18mW，用力约为自身体重的16倍。约100 mm的跳跃距离不受温度影响。这一点，以及每质量肌肉所需的740 W kg（-1）的功率，表明使用了弹射机制。弹性蛋白Resilin在中腿和后腿的翼铰链与侧脊背头的关节处的四个垫中显示。相比之下，跳蚤只使用后腿跳跃，只有两个弹性蛋白垫。因此，这提供了一个功能的参考点，考虑雪蚤和真蚤之间的系统发育关系。
Flightless snow fleas (snow scorpion flies, Mecoptera, Boreidae) live as adults during northern hemisphere winters, often jumping and walking on the surface of snow. Their jumping mechanisms and performance were analysed with high speed imaging. Jumps were propelled by simultaneous movements of both the middle and hind pairs of legs, as judged by the 0.2ms resolution afforded by image rates of 5000 frames. s(-1). The middle legs of males represent 140% and the hindlegs 187% of the body length (3.4mm), and the ratio of leg lengths is 1:1.3:1.7 (front: middle: hind). In preparation for a jump the middle legs and hindlegs were rotated forwards at their coxal joints with the fused mesothorax and metathorax. The first propulsive movement of a jump was the rotation of the trochantera about the coxae, powered by large depressor muscles within the thorax. The acceleration time was 6.6 ms. The fastest jump by a male had a take-off velocity of 1m s(-1), which required 1.1 mu J of energy and a power output of 0.18mW, and exerted a force about 16 times its body weight. Jump distances of about 100mm were unaffected by temperature. This, and the power per mass of muscle requirement of 740 W kg(-1), suggests that a catapult mechanism is used. The elastic protein resilin was revealed in four pads at the articulation of the wing hinge with the dorsal head of the pleural ridge of each middle leg and hindleg. By contrast, fleas, which use just their hindlegs for jumping, have only two pads of resilin. This, therefore, provides a functional reference point for considerations about the phylogenetic relationships between snow fleas and true fleas.