Feller K D, Cronin T W
University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA
University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA.
J Exp Biol. 2014 Sep 15;217(Pt 18):3263-73. doi: 10.1242/jeb.108076.
Opaque screening pigments are a fundamental requisite for preserving resolution in image-forming eyes. Possession of any type of image-forming eye in a transparent, pelagic animal will thus undermine the ability of that animal to be invisible in the water column. Transparent, pelagic animals must therefore deal with the trade-off between the ability to see and the ability of other animals to see them. Stomatopod larvae, like many transparent crustaceans, possess specialized optics in their compound eyes that minimize the volume of the opaque retina. Though the volumes of these retinas are reduced, their opacity remains conspicuous to an observer. The light reflected from structures overlying the retinas of stomatopod crustacean larval eyes, referred to here as eyeshine, is hypothesized to further reduce the visibility of opaque retinas. Blue or green wavelengths of light are most strongly reflected in stomatopod larval eyeshine, suggesting a putative spectral matching to the light environment against which the larval eyes are viewed. We tested the efficacy of stomatopod crustacean larval eyeshine as an ocular camouflaging mechanism by photographing larvae in their natural light environment and analysing the contrast of eyes with the background light. To test for spectral matching between stomatopod larval eyeshine and the background light environment, we characterized the spectrum of eyeshine and calculated its performance using radiometric measurements collected at the time of each photographic series. These results are the first to demonstrate an operative mirror camouflage matched in both spectrum and radiance to the pelagic background light environment.
不透明的屏蔽色素是在成像眼睛中保持分辨率的基本要素。因此，在透明的远洋动物中拥有任何类型的成像眼睛都会削弱该动物在水柱中隐形的能力。所以，透明的远洋动物必须在视觉能力和被其他动物看到的能力之间进行权衡。口足类幼虫，就像许多透明的甲壳类动物一样，在其复眼中拥有专门的光学结构，可将不透明视网膜的体积最小化。尽管这些视网膜的体积减小了，但它们的不透明度对观察者来说仍然很明显。从口足类甲壳动物幼虫眼睛视网膜上方的结构反射的光，在这里称为眼耀光，据推测它会进一步降低不透明视网膜的可见性。口足类幼虫的眼耀光中蓝光或绿光波长的反射最强，这表明它可能与幼虫眼睛所处的光环境在光谱上相匹配。我们通过在自然光环境下拍摄幼虫并分析眼睛与背景光的对比度，测试了口足类甲壳动物幼虫眼耀光作为一种眼部伪装机制的效果。为了测试口足类幼虫眼耀光与背景光环境之间的光谱匹配，我们对眼耀光的光谱进行了表征，并使用在每个摄影系列时收集的辐射测量数据计算其性能。这些结果首次证明了一种在光谱和辐射度上都与远洋背景光环境相匹配的有效镜面伪装。
