科学美国人60秒 SSS This Caterpillar Whistles While It Irks

This Caterpillar 1 Whistles While It Irks

毛虫会吹口哨？还是一种恐吓战术？

Songbirds produce a rich repertoire 2 of sounds: songs, of course, but also chatter 3 calls, flight calls and alarm calls: like this high-pitched warning from a black-capped chickadee: < seet call >. But chickadees aren't the only ones endowed with chirping 4 abilities. Turns out a certain type of caterpillar can, too. < caterpillar whistle > Once again, the bird, then the caterpillar. <seet call, caterpillar whistle > Sounds pretty darn similar.

鸣禽能发出各种丰富的声音：包括歌唱，交流鸣叫、飞行鸣叫和警报呼叫。比如黑顶山雀发出的高音警告。但山雀并非唯一拥有鸣叫功能的动物。事实证明，某种类型的毛虫也拥有这种能力。再听一次，先是鸟鸣，然后是毛虫发出的声音。（两种声音）听起来非常像。

\"Yeah it's pretty crazy." Jessica Lindsay is a biologist at the University of Washington. She says this species, the North American walnut 5 sphinx caterpillar, makes the sound using tiny pairs of breathing holes, called spiracles. "They compress themselves lengthwise like an accordion 6 and so that compression pushes air out of the spiracles, making whistling sounds."

“是的，这很疯狂。”杰西卡·琳赛是华盛顿大学的一名生物学家。她说，北美胡桃木毛虫这一物种，通过被称为“气门”的微小的呼吸孔发出此种声音。“他们像手风琴一样把自己压缩得很长，这种压缩会把空气从气门里吹出来，发出吹口哨的声音。”

A cool coincidence, for sure. But here's where it gets interesting. Lindsay then played the caterpillar whistle through a speaker near a bird feeder. And the birds—of many different species—dove for cover. "Sometimes we'd see nuthatches flicking 7 their wings, which is a big sign of distress 8 for them. Sometimes it would take a really long time to return to feeding, which is a big indicator 9 that they were taking that whistling noise pretty seriously."

当然，这只是一个很酷的巧合。但有一个很有趣的现象。琳赛在一个喂鸟器近用一个扬声器播放了毛虫的口哨声。这时，黑顶山雀以及其他许多不同种类的鸟都纷纷去寻找掩护。“有时我们会看到五子雀拍打着它们的翅膀——这对它们来说表示巨大不幸的信号。有时鸟儿们需要很长时间才能恢复进食——这在很大程度上表明它们把毛虫的口哨声当真了。”

And whereas the birds were unperturbed by the song of a house finch—a control sound—they responded to the caterpillar whistles with almost the same urgency as when they heard that real alarm call <seet call> from a chickadee. Suggesting the caterpillars 10… are onto something. "They're basically using bird speak to say that there's a dangerous predator 11 in the area and that the birds better get into cover."

然而，鸟儿们却没有受到家朱雀歌声的干扰——一种控制声音。它们听到毛虫发出的哨声做出的紧急反应，与它们听到黑顶山雀发出的真正的警报呼叫时反应几乎相同。这就说明毛虫……在表达一些信息。“基本上，它们就是在用鸟类的语言说，这里有一个危险的捕食者，鸟儿们最好赶紧找掩护。”

Lindsay presented the results at the International Symposium 12 on Acoustic 13 Communication by Animals in Omaha.

琳赛在奥马哈举行的国际动物声学传播研讨会上展示了这一结果。

Previous work suggests the caterpillars whistle when pecked at by birds. And they sometimes squeal 14, too: <caterpillar squeal> Suggesting they may have more than one scare tactic 15, to worm their way out of trouble.

之前的研究表明，毛虫在被鸟儿啄食时就会发出口哨声。它们有时也会尖叫。这表明它们可能会用不止一种恐吓战术来摆脱麻烦。