Environmental Optics Laboratory, Department of Biological Physics, Physical Institute, Eötvös University, H-1117 Budapest, Pázmány sétány 1, Hungary.
Physiol Behav. 2012 Feb 28;105(4):1067-75. doi: 10.1016/j.physbeh.2011.11.020. Epub 2011 Dec 1.
The strongest known circular polarization of biotic origin is the left-circularly polarized (LCP) light reflected from the metallic shiny exocuticle of certain beetles of the family Scarabaeidae. This phenomenon has been discovered by Michelson in 1911. Although since 1955 it has been known that the human eye perceives a visual illusion when stimulated by circularly polarized (CP) light, it was discovered only recently that a stomatopod shrimp is able to perceive circular polarization. It is pertinent to suppose that scarab beetles reflecting LCP light in an optical environment (vegetation) being deficient in CP signals may also perceive circular polarization and use it to find each other (mate/conspecifics) as until now it has been believed. We tested this hypothesis in six choice experiments with several hundred individuals of four scarab species: Anomala dubia, Anomala vitis (Coleoptera, Scarabaeidae, Rutelinae), and Cetonia aurata, Potosia cuprea (Coleoptera, Scarabaeidae, Cetoniinae), all possessing left-circularly polarizing exocuticle. From the results of our experiments we conclude that the studied four scarab species are not attracted to CP light when feeding or looking for mate or conspecifics. We demonstrated that the light reflected by host plants of the investigated scarabs is circularly unpolarized. Our results finally solve a puzzle raised over one hundred years ago, when Michaelson discovered that scarab beetles reflect circularly polarized light.
已知最强的生物起源圆偏振光是某些金龟子科甲虫的金属光泽外骨骼反射的左旋圆偏振（LCP）光。这一现象是 Michelson 在 1911 年发现的。尽管自 1955 年以来，人们已经知道人眼在受到圆偏振（CP）光刺激时会产生视觉错觉，但直到最近才发现，一种螳螂虾能够感知圆偏振。可以合理假设，在 CP 信号不足的光学环境（植被）中反射 LCP 光的甲虫也可能感知圆偏振，并利用它来寻找彼此（配偶/同种），因为到目前为止，人们一直认为是这样。我们在六个选择实验中用几百只四种金龟子（鞘翅目，金龟科， Rutelinae 属：Anomala dubia，Anomala vitis；以及鞘翅目，金龟科， Cetoniinae 属：Cetonia aurata，Potosia cuprea）进行了这项假设测试，它们都具有左旋圆极化外骨骼。从我们的实验结果可以得出结论，研究的四种金龟子在觅食或寻找配偶或同种时，不会被 CP 光吸引。我们证明了被研究的金龟子的寄主植物反射的光是圆偏振的。我们的结果最终解决了一个一百多年前提出的难题，当时 Michaelson 发现金龟子反射圆偏振光。
