Evolutionary Ecology Research Group, Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Strasse 17, 10315 Berlin, Germany.
Biol Lett. 2011 Oct 23;7(5):793-5. doi: 10.1098/rsbl.2011.0313. Epub 2011 May 4.
Similar to insects, birds and pterosaurs, bats have evolved powered flight. But in contrast to other flying taxa, only bats are furry. Here, we asked whether flight is impaired when bat pelage and wing membranes get wet. We studied the metabolism of short flights in Carollia sowelli, a bat that is exposed to heavy and frequent rainfall in neotropical rainforests. We expected bats to encounter higher thermoregulatory costs, or to suffer from lowered aerodynamic properties when pelage and wing membranes catch moisture. Therefore, we predicted that wet bats face higher flight costs than dry ones. We quantified the flight metabolism in three treatments: dry bats, wet bats and no rain, wet bats and rain. Dry bats showed metabolic rates predicted by allometry. However, flight metabolism increased twofold when bats were wet, or when they were additionally exposed to rain. We conclude that bats may not avoid rain only because of sensory constraints imposed by raindrops on echolocation, but also because of energetic constraints.
与昆虫、鸟类和翼龙类似，蝙蝠也进化出了有动力的飞行能力。但与其他飞行生物不同的是，只有蝙蝠有皮毛。在这里，我们研究了当蝙蝠的皮毛和翅膀膜变湿时，飞行是否会受到影响。我们研究了短距离飞行的代谢过程Carollia sowelli，这是一种生活在新热带雨林中的蝙蝠，经常遭受强降雨的侵袭。我们预计当皮毛和翅膀膜吸收水分时，蝙蝠会遇到更高的体温调节成本，或者受到降低的空气动力学性能的影响。因此，我们预测潮湿的蝙蝠比干燥的蝙蝠面临更高的飞行成本。我们在三种处理方式下量化了飞行代谢：干燥的蝙蝠、潮湿的蝙蝠和没有降雨的情况、潮湿的蝙蝠和降雨的情况。干燥的蝙蝠表现出了根据比例定律预测的代谢率。然而，当蝙蝠变湿时，或者当它们额外暴露在雨中时，飞行代谢率增加了两倍。我们的结论是，蝙蝠可能不仅因为雨滴对回声定位的感官限制而避免降雨，还因为能量限制。
