Zoology Department, University of Cape Town, Rondebosch, Cape Town, South Africa.
Biol Lett. 2012 Jun 23;8(3):390-2. doi: 10.1098/rsbl.2011.1022. Epub 2011 Dec 7.
We report on a newly discovered cockroach (Saltoblattella montistabularis) from South Africa, which jumps and therefore differs from all other extant cockroaches that have a scuttling locomotion. In its natural shrubland habitat, jumping and hopping accounted for 71 per cent of locomotory activity. Jumps are powered by rapid and synchronous extension of the hind legs that are twice the length of the other legs and make up 10 per cent of the body weight. In high-speed images of the best jumps the body was accelerated in 10 ms to a take-off velocity of 2.1 m s(-1) so that the cockroach experienced the equivalent of 23 times gravity while leaping a forward distance of 48 times its body length. Such jumps required 38 µJ of energy, a power output of 3.4 mW and exerted a ground reaction force through both hind legs of 4 mN. The large hind legs have grooved femora into which the tibiae engage fully in advance of a jump, and have resilin, an elastic protein, at the femoro-tibial joint. The extensor tibiae muscles contracted for 224 ms before the hind legs moved, indicating that energy must be stored and then released suddenly in a catapult action to propel a jump. Overall, the jumping mechanisms and anatomical features show remarkable convergence with those of grasshoppers with whom they share their habitat and which they rival in jumping performance.
我们报告了一种新发现的蟑螂（Saltoblattella montistabularis），来自南非，它会跳跃，因此与所有其他现存的以爬行方式移动的蟑螂不同。在其自然的灌木丛生境中，跳跃和跳跃占运动活动的 71%。跳跃是由后腿的快速和同步伸展提供动力的，后腿的长度是其他腿的两倍，占体重的 10%。在最佳跳跃的高速图像中，身体在 10 毫秒内加速到 2.1 m s(-1)的起飞速度，因此蟑螂在跳跃 48 倍体长的距离时，会经历相当于 23 倍重力的加速度。这样的跳跃需要 38 µJ 的能量，输出功率为 3.4 mW，并通过两条后腿施加 4 mN 的地面反作用力。后腿的股骨上有凹槽，胫骨在跳跃前完全嵌入其中，并且在股胫关节处有弹性蛋白。在后腿移动之前，伸肌胫骨肌肉收缩了 224 ms，这表明能量必须被储存起来，然后突然释放，以产生弹射作用来推动跳跃。总的来说，跳跃机制和解剖特征与它们共享生境的蝗虫有显著的趋同，并且在跳跃性能上与蝗虫相媲美。
