近日,，一項新的研究發(fā)現,，斑馬紋可干擾采采蠅和馬蠅用來尋找水和食物的光模式。相關論文發(fā)表在The Journal of Experimental Biology上,。因此,，如果你要去非洲旅行，記得帶上一件斑馬紋的襯衣,。
專家表示,，該發(fā)現是解決為什么在斑馬身上會產生這種獨特的花紋這個謎題上的一個令人激動的進展,。“這是從人們開始討論這個話題120年以來第一次真正有說服力的證據，”并未參與該項煙酒店餓加州大學行為生態(tài)學家Tim Caro說道,。
人們對斑馬的條紋進行了多年的推測,，各種理由都有，比如迷惑捕食者,、便于在草叢中偽裝,、利于同伴在龐大的獸群中找到彼此等等。
但是沒有人對這些假說進行實驗驗證,，這項新研究的作者,、瑞典蘭德大學的進化生物學家Susanne ?kesson說。她對斑馬是否容易招虻類昆蟲感到很好奇,。虻是一類臭名昭著的昆蟲,，包括采采蠅和馬蠅，會傳染諸如昏睡癥和美洲錐蟲病等疾病,。早期有關虻蠅對黑色,、白色或條紋著陸面的偏好性實驗發(fā)現，它們更喜歡黑色方塊,，但是沒有解釋為什么,。
?kesson和她的同事從她們對馬蠅的認識開始著手研究。他們此前的研究發(fā)現,，相比于白馬,，深顏色的馬更容易招蟲子，因為深顏色的外皮反射同一方向的光,。這種極化的光與蠅類產卵用的水池所反射的光是一樣的,。而白色外皮則不能反射這種極化光。
為了考證斑馬的白色條帶是否對虻類的吸引力較低,，該研究團隊在一個馬場設置了一系列的實驗,。他們測試了純黑、純白以及黑白相間方塊對虻類的吸引力,，也測試了與真馬同樣大的黑色,、棕色、白色或帶狀外表的塑料馬對虻類的吸引力,。他們還以各種數量及寬度的灰色方塊來測試花紋模式對馬蠅偏好性的影響,。研究者們用植物油來吸引虻落下，并且在塑料馬上涂上無色無味的膠水來粘住落下的虻,。
結果發(fā)現,，條狀對虻的吸引力甚至還不如純黑色的吸引力強。這是因為條狀花紋反射多種模式的光，相反,，純黑色則反射這些蠅類喜歡的統(tǒng)一模式的光,，作者們說。因此,，即使是純白方塊也比條狀更有吸引力,。該研究結果發(fā)表在The Journal of Experimental Biology上。
該團隊強調,，他們的研究結果需要在生活在自然棲息地的斑馬上進一步確認,。氣味能讓顏色更加吸引虻蠅，他們指出,，而野外的斑馬發(fā)出的氣味非常強烈,，這種氣味可能會使覓食的虻類忽視視覺上的不適。
斑馬并不會在空曠的平地中遭遇,，虻蠅，Caro說,。不過kesson指出,，斑馬和虻蠅都會在水邊逗留。
盡管存在這些需要特別說明的問題,，這還是一項非常令人激動的工作,，Ruxton說。這無疑是有關斑馬條紋的最為嚴密的實驗,，他說,。(生物谷Bioon.com)
doi:10.1242/jeb.065540
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Polarotactic tabanids find striped patterns with brightness and/or polarization modulation least attractive: an advantage of zebra stripes
Ádám Egri, Miklós Blahó, György Kriska, Róbert Farkas, Mónika Gyurkovszky, Susanne Åkesson and Gábor Horváth
The characteristic striped appearance of zebras has provoked much speculation about its function and why the pattern has evolved, but experimental evidence is scarce. Here, we demonstrate that a zebra-striped horse model attracts far fewer horseflies (tabanids) than either homogeneous black, brown, grey or white equivalents. Such biting flies are prevalent across Africa and have considerable fitness impact on potential mammalian hosts. Besides brightness, one of the likely mechanisms underlying this protection is the polarization of reflected light from the host animal. We show that the attractiveness of striped patterns to tabanids is also reduced if only polarization modulations (parallel stripes with alternating orthogonal directions of polarization) occur in horizontal or vertical homogeneous grey surfaces. Tabanids have been shown to respond strongly to linearly polarized light, and we demonstrate here that the light and dark stripes of a zebra’s coat reflect very different polarizations of light in a way that disrupts the attractiveness to tabanids. We show that the attractiveness to tabanids decreases with decreasing stripe width, and that stripes below a certain size are effective in not attracting tabanids. Further, we demonstrate that the stripe widths of zebra coats fall in a range where the striped pattern is most disruptive to tabanids. The striped coat patterns of several other large mammals may also function in reducing exposure to tabanids by similar mechanisms of differential brightness and polarization of reflected light. This work provides an experimentally supported explanation for the underlying mechanism leading to the selective advantage of a black-and-white striped coat pattern.
