Catania Kenneth C
Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America.
PLoS One. 2008;3(10):e3472. doi: 10.1371/journal.pone.0003472. Epub 2008 Oct 14.
For generations many families in and around Florida's Apalachicola National Forest have supported themselves by collecting the large endemic earthworms (Diplocardia mississippiensis). This is accomplished by vibrating a wooden stake driven into the soil, a practice called "worm grunting". In response to the vibrations, worms emerge to the surface where thousands can be gathered in a few hours. Why do these earthworms suddenly exit their burrows in response to vibrations, exposing themselves to predation?
Here it is shown that a population of eastern American moles (Scalopus aquaticus) inhabits the area where worms are collected and that earthworms have a pronounced escape response from moles consisting of rapidly exiting their burrows to flee across the soil surface. Recordings of vibrations generated by bait collectors and moles suggest that "worm grunters" unknowingly mimic digging moles. An alternative possibility, that worms interpret vibrations as rain and surface to avoid drowning is not supported.
Previous investigations have revealed that both wood turtles and herring gulls vibrate the ground to elicit earthworm escapes, indicating that a range of predators may exploit the predator-prey relationship between earthworms and moles. In addition to revealing a novel escape response that may be widespread among soil fauna, the results show that humans have played the role of "rare predators" in exploiting the consequences of a sensory arms race.
几代以来，佛罗里达州阿巴拉契科拉国家森林及其周边的许多家庭通过采集当地特有的大型蚯蚓（密西西比双心蚓）维持生计。这是通过振动一根插入土壤中的木桩来实现的，这种做法叫做“诱蚓发声”。作为对振动的反应，蚯蚓会爬到地表，几个小时内就能聚集数千条。为什么这些蚯蚓会因振动突然离开洞穴，将自己暴露于被捕食的风险中呢？
研究表明，美国东部鼹鼠（美洲鼹）种群栖息在蚯蚓采集区域，并且蚯蚓对鼹鼠有明显的逃避反应，即迅速离开洞穴，在土壤表面逃窜。诱饵采集者和鼹鼠产生的振动记录表明，“诱蚓发声者”在不知不觉中模仿了挖掘的鼹鼠。蚯蚓将振动解读为降雨并爬到地表以避免溺水这种另一种可能性未得到证实。
先前的研究表明，木雕水龟和银鸥都会振动地面来引发蚯蚓逃窜，这表明一系列捕食者可能利用了蚯蚓与鼹鼠之间的捕食关系。除了揭示一种可能在土壤动物中广泛存在的新逃避反应外，研究结果还表明，人类在利用感官军备竞赛的后果方面扮演了“罕见捕食者”的角色。
