許多動(dòng)物利用保護(hù)色來逃避獵捕,,包括利用斑紋降低被天敵發(fā)現(xiàn)的風(fēng)險(xiǎn)(偽裝),,向天敵暗示自己有毒或不可食用(警告色),,或者裝扮成其它動(dòng)物或物體(“擬態(tài)”和“偽裝”),。
除此以外,,很多小動(dòng)物例如蝴蝶,、蛾子和魚類擁有兩對甚至多對“眼點(diǎn)”(eye spot)。許多眼點(diǎn)能嚇跑掠食者,,可以十分有效地防止天敵的攻擊,。在過去長達(dá)150年里,人們都認(rèn)定這是因?yàn)檠埸c(diǎn)模仿了掠食者自己的天敵的眼睛的緣故,。但是,由劍橋大學(xué)的動(dòng)物學(xué)家Martin Stevens,、Chloe Hardman 和Claire Stubbins等人進(jìn)行的最近研究表明,,這一流行觀點(diǎn)沒有任何實(shí)驗(yàn)依據(jù)。
根據(jù)2月13日在線發(fā)表于《行為生態(tài)學(xué)》(Behavioral Ecology)上的研究結(jié)果,,蝴蝶等小動(dòng)物身上的環(huán)狀斑紋能有效對抗掠食者,,是因?yàn)檫@些斑紋本身十分顯眼,而不是因?yàn)樗鼈兡7铝寺邮痴咛鞌车难劬Α?/p>
Stevens,、Hardman和Stubbins用防潮紙做成假蛾子,,把各種形狀、各種大小,、數(shù)目不等,、對眼睛模仿程度不一的眼點(diǎn)組成嚇人的圖案,用高清打印機(jī)打印到紙上,,他們在這些假蛾子身上拴上小蟲子,,然后釘?shù)铰淙~混交林里的各種樹上,觀測野生鳥類對這些假蛾子的反應(yīng),。
動(dòng)物學(xué)家發(fā)現(xiàn),,與其它印著顯著圖案的人造蛾子相比,身上帶有環(huán)狀斑紋的人造蛾子受到的攻擊不見得更少,。他們發(fā)現(xiàn),,總的說來,最能嚇退掠食者的眼點(diǎn)恰恰是那些花紋最大,、最多,、最顯眼的眼點(diǎn)。
Stevens博士解釋說:“和那些身帶眼狀斑紋的假蛾子相比,,鳥兒們一樣不喜歡長著條形和方形圖案的蛾子,。由此我們可以斷言,眼點(diǎn)是否奏效,,主要看它們是否鮮艷和顯眼,,而不是因?yàn)樗鼈兡7铝寺邮痴咛鞌车难劬Α_@說明很多動(dòng)物身上的環(huán)形斑紋,,并不是像很多人說的那樣,,是在模仿其它動(dòng)物的眼睛,。”(科學(xué)網(wǎng) 崔月雷/編譯)
生物谷推薦原始出處:
(Behavioral Ecology),doi:10.1093/beheco/arm162,,Martin Stevens, Claire L. Stubbins
Conspicuousness, not eye mimicry, makes "eyespots" effective antipredator signals
Martin Stevens, Chloe J. Hardman and Claire L. Stubbins
Abstract
Many animals bear colors and patterns to reduce the risk of predation from visually hunting predators, including warning colors, camouflage, and mimicry. In addition, various species possess paired circular features often called "eyespots," which may intimidate or startle predators preventing or postponing an attack. Most explanations for how eyespots work assert that they mimic the eyes of the predators own enemies. However, recent work has indicated that spots may reduce the risk of predation based purely on how conspicuous they are to a predator's visual system. Here, we use a field technique involving artificial prey marked with stimuli of various shapes, numbers, and sizes, presented to avian predators in the field, to distinguish between the eye mimicry and conspicuousness theories. In 3 experiments, we find that the features which make effective antipredator wing markings are large size and higher numbers of spots. Stimuli with circles survived no better than those marked with other conspicuous shapes such as bars, and changing the spatial construction of the spots to increase the level of eye mimicry had no effect on the protective value of the spots. These experiments support other recent work indicating that conspicuousness, and not eye mimicry, is important in promoting avoidance behavior in predators and that eyespots on real animals need not necessarily, as most accounts claim, mimic the eyes of other animals.