Kelber Almut, Balkenius Anna, Warrant Eric J
Department of Cell and Organism Biology, Vision Group, Lund University, Helgonavägen 3, S-22362 Lund, Sweden.
Nature. 2002 Oct 31;419(6910):922-5. doi: 10.1038/nature01065.
Humans are colour-blind at night, and it has been assumed that this is true of all animals. But colour vision is as useful for discriminating objects at night as it is during the day. Here we show, through behavioural experiments, that the nocturnal hawkmoth Deilephila elpenor uses colour vision to discriminate coloured stimuli at intensities corresponding to dim starlight (0.0001 cd x m(-2)). It can do this even if the illumination colour changes, thereby showing colour constancy-a property of true colour vision systems. In identical conditions humans are completely colour-blind. Our calculations show that the possession of three photoreceptor classes reduces the absolute sensitivity of the eye, which indicates that colour vision has a high ecological relevance in nocturnal moths. In addition, the photoreceptors of a single ommatidium absorb too few photons for reliable discrimination, indicating that spatial and/or temporal summation must occur for colour vision to be possible. Taken together, our results show that colour vision occurs at nocturnal intensities in a biologically relevant context.
人类在夜间是色盲，人们一直认为所有动物都是如此。但颜色视觉在夜间辨别物体时与白天一样有用。在这里，我们通过行为实验表明，夜间活动的鹰蛾（榆绿天蛾）能够利用颜色视觉在对应于昏暗星光（0.0001坎德拉·米-2）的强度下辨别有色刺激物。即使照明颜色发生变化，它也能做到这一点，从而展现出颜色恒常性——这是真正的颜色视觉系统的一种特性。在相同条件下，人类则完全是色盲。我们的计算表明，拥有三类光感受器会降低眼睛的绝对灵敏度，这表明颜色视觉在夜间蛾类中具有很高的生态相关性。此外，单个小眼的光感受器吸收的光子太少，无法进行可靠的辨别，这表明颜色视觉要成为可能，必须进行空间和/或时间总和。综上所述，我们的结果表明，在与生物学相关的环境中，颜色视觉在夜间强度下会出现。
