蝙蝠使用超声波回声定位，但它们捕食的一些飞蛾能感知到蝙蝠发出的超声波并据此躲避。英国一项最新研究说，一些蝙蝠因此又进化出了类似“隐形战机”的功能，可以改变所发出的超声波，让飞蛾难以察觉自己的存在。

英国布里斯托尔大学研究人员在新一期《当代生物学》（Current Biology）杂志上报告说，在蝙蝠与飞蛾之间长期的互动进化中，一些飞蛾已经可以感知到蝙蝠发出的超声波，从而躲避蝙蝠的捕食。但研究人员发现欧洲宽耳蝠仍然可以捕食到这些飞蛾，因此他们分析了这种蝙蝠发出的超声波。

研究人员发现，欧洲宽耳蝠在捕食飞蛾时会大幅降低所发出的超声波的振幅，与其他蝙蝠发出的高振幅超声波相比，其“安静”程度可提高约百倍。研究人员又在飞蛾耳中装入微小的探测器，记录它在听到不同超声波时耳朵神经的信号变化，结果也证实，其他种类的蝙蝠离飞蛾约30米时就会被飞蛾发觉，而具有“隐形”本领的欧洲宽耳蝠可逼近到3．5米还不被飞蛾察觉。

原文出处：

Current Biology　doi：10.1016/j.cub.2010.07.046

An Aerial-Hawking Bat Uses Stealth Echolocation to Counter Moth Hearing
Holger R. Goerlitz, Hannah M. ter Hofstede, Matt R.K. Zeale, Gareth Jones, Marc W. Holderied

Ears evolved in many nocturnal insects, including some moths, to detect bat echolocation calls and evade capture [1,2]. Although there is evidence that some bats emit echolocation calls that are inconspicuous to eared moths, it is difficult to determine whether this was an adaptation to moth hearing or originally evolved for a different purpose [2,3]. Aerial-hawking bats generally emit high-amplitude echolocation calls to maximize detection range [4,5]. Here we present the first example of an echolocation counterstrategy to overcome prey hearing at the cost of reduced detection distance. We combined comparative bat flight-path tracking and moth neurophysiology with fecal DNA analysis to show that the barbastelle, Barbastella barbastellus, emits calls that are 10 to 100 times lower in amplitude than those of other aerial-hawking bats, remains undetected by moths until close, and captures mainly eared moths. Model calculations demonstrate that only bats emitting such low-amplitude calls hear moth echoes before their calls are conspicuous to moths. This stealth echolocation allows the barbastelle to exploit food resources that are difficult to catch for other aerial-hawking bats emitting calls of greater amplitude.