據(jù)美國生活科學(xué)網(wǎng)站報道，科學(xué)家最新研究顯示,，毛毛蟲可以吹口哨,，發(fā)出吱吱尖叫，讓掠食者鳥類望而卻步,。
毛毛蟲并不能皺褶嘴唇吹口哨,，因為它們并沒有嘴唇，代替這一功能的是吹動身體兩側(cè)的通氣孔,。100多年前,，科學(xué)家們就知道一些毛毛蟲可以產(chǎn)生咔嚓聲或者嘯嘯的噪音。然而,，直到近期研究人員才開始用實驗手段調(diào)查這些噪音是如何發(fā)出的,，以及它們具有何種作用。
加拿大渥太華市卡爾頓大學(xué)神經(jīng)行為研究專家杰恩-亞克(Jayne Yack)顯示,，絲蛾毛毛蟲(學(xué)名為：Antheraea polyphemus)通過猛咬下顎產(chǎn)生咔嚓聲,。目前,，她和同事們首次揭示胡桃毛毛蟲(學(xué)名為：Amorpha juglandis)可從兩側(cè)發(fā)出短鳴。
使用高速攝像儀器,，研究人員發(fā)現(xiàn)這些毛毛蟲在“吹口哨”時,，有意地將頭部向后縮，壓縮身體兩側(cè)的通氣孔,。不同于爬行動物,、鳥類和哺乳動物，昆蟲不會使用口腔進行呼吸,，而是使用身體兩側(cè)的通氣孔(spiracles)進行呼吸,。科學(xué)家發(fā)現(xiàn)毛毛蟲通過壓迫通氣孔中的氣體產(chǎn)生口哨,，從而產(chǎn)生嘯嘯的噪音,。
卡爾頓大學(xué)研究員為了證實他們的觀點，輕輕地將乳膠涂在毛毛蟲兩側(cè)的8對通氣孔,，在捕捉幼體毛毛蟲時,，有序地揭開每對通氣孔。研究結(jié)果顯示,，嘯嘯噪音是從這8對通氣孔中傳出來,，每對通氣孔產(chǎn)生的嘯聲可持續(xù)4秒，其聲音頻率可使鳥類和人類聽到,，并覆蓋超聲波段,。
絲蛾毛毛蟲發(fā)出的咔嚓聲可以警告掠食者，告誡它們自己是令人討厭的食物,，但胡桃毛毛蟲發(fā)出的短鳴卻意味著什么呢,？為了揭示其中的奧秘，亞克在加拿大皇后大學(xué)研究人員的協(xié)助下研究了黃鶯(學(xué)名為：Dendroica petechia),，這種鳥類經(jīng)常吞食毛毛蟲,，并生活在胡桃毛毛蟲棲息的區(qū)域。
在研究實驗中,，科學(xué)家將胡桃毛毛蟲放在黃鶯籠子旁的樹枝上,，并耐心地拍攝期間發(fā)生的狀況。令他們吃驚的是,，當(dāng)黃鶯試圖展開攻擊時,，毛毛蟲發(fā)生的“口哨”使黃鶯退縮畏懼，單足回跳或者快速飛離,。在觀測的一段時間內(nèi),，黃鶯展開了兩次攻擊，卻均被嚇退,，而毛毛蟲毫無損傷,。
亞克說：“黃鶯被突如其來的毛毛蟲噪音所震驚,，這些噪音或許不能說明胡桃毛毛蟲是味道不佳的食物，但鳥兒卻顯然出現(xiàn)震驚,，這是由該聲音是預(yù)料之外的,。”目前,，這項最新研究發(fā)表在12月10日出版的《實驗生物學(xué)》雜志上,。（生物谷Bioon.com）
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生物谷推薦原文出處：
Journal of Experimental Biology doi: 10.1242/jeb.046805
Whistling in caterpillars (Amorpha juglandis, Bombycoidea): sound-producing mechanism and function
Veronica L. Bura1, Vanya G. Rohwer2, Paul R. Martin2 and Jayne E. Yack1,*
1 Department of Biology, Carleton University, Ottawa, ON, Canada, K1S 5B6
2 Department of Biology, Queen's University, Kingston, ON, Canada, K7L 3N6
* Author for correspondence ([email protected])
Caterpillar defenses have been researched extensively, and, although most studies focus on visually communicated signals, little is known about the role that sounds play in defense. We report on whistling, a novel form of sound production for caterpillars and rare for insects in general. The North American walnut sphinx (Amorpha juglandis) produces whistle ‘trains’ ranging from 44 to 2060 ms in duration and comprising one to eight whistles. Sounds were categorized into three types: broadband, pure whistles and multi-harmonic plus broadband, with mean dominant frequencies at 15 kHz, 9 kHz and 22 kHz, respectively. The mechanism of sound production was determined by selectively obstructing abdominal spiracles, monitoring air flow at different spiracles using a laser vibrometer and recording body movements associated with sound production using high-speed video. Contractions of the anterior body segments always accompanied sound production, forcing air through a pair of enlarged spiracles on the eighth abdominal segment. We tested the hypothesis that sounds function in defense using simulated attacks with blunt forceps and natural attacks with an avian predator – the yellow warbler (Dendroica petechia). In simulated attacks, 94% of caterpillars responded with whistle trains that were frequently accompanied by directed thrashing but no obvious chemical defense. In predator trials, all birds readily attacked the caterpillar, eliciting whistle trains each time. Birds responded to whistling by hesitating, jumping back or diving away from the sound source. We conclude that caterpillar whistles are defensive and propose that they function specifically as acoustic ‘eye spots’ to startle predators.
Key words: sound production, caterpillar, acoustic communication, defense, Amorpha juglandis, whistle, yellow warbler
