Briscoe Adriana D, Bernard Gary D, Szeto Allan S, Nagy Lisa M, White Richard H
Department of Ecology and Evolutionary Biology, 321 Steinhaus Hall, University of California, Irvine, CA 92697, USA.
J Comp Neurol. 2003 Apr 14;458(4):334-49. doi: 10.1002/cne.10582.
Surveys of spectral sensitivities, visual pigment spectra, and opsin gene sequences have indicated that all butterfly eyes contain ultraviolet-, blue-, and green-sensitive rhodopsins. Some species also contain a fourth or fifth type, related in amino acid sequence to green-sensitive insect rhodopsins, but red shifted in absorbance. By combining electron microscopy, epi-microspectrophotometry, and polymerase chain reaction cloning, we found that the compound eye of Vanessa cardui has the typical ultrastructural features of the butterfly retina but contains only the three common insect rhodopsins. We estimated lambda-max values and relative densities of the rhodopsins in the Vanessa retina (0.72, P530; 0.12, P470; and 0.15, P360) from microspectrophotometric measurements and calculations based on a computational model of reflectance spectra. We isolated three opsin-encoding cDNA fragments that were identified with P530, P470, and P360 by homology to the well-characterized insect rhodopsin families. The retinal mosaic was mapped by opsin mRNA in situ hybridization and found to contain three kinds of ommatidia with respect to their patterns of short wavelength rhodopsin expression. In some ommatidia, P360 or P470 was expressed in R1 and R2 opposed receptor cells; in others, one cell expressed P360, whereas its complement expressed P470. P530 was expressed in the other seven cells of all ommatidia. P470-expressing cells were abundant in the ventral retina but nearly absent dorsally. Our results indicated that there are major differences between the color vision systems of nymphalid and papilionid butterflies: the nymphalid Vanessa has a simpler, trichromatic, system than do the tetrachromatic papilionids that have been studied.
对光谱敏感性、视觉色素光谱和视蛋白基因序列的调查表明,所有蝴蝶的眼睛都含有对紫外线、蓝光和绿光敏感的视紫红质。一些物种还含有第四种或第五种视紫红质,其氨基酸序列与对绿光敏感的昆虫视紫红质相关,但吸收峰发生了红移。通过结合电子显微镜、落射显微分光光度法和聚合酶链反应克隆,我们发现菜粉蝶的复眼具有蝴蝶视网膜典型的超微结构特征,但只含有三种常见的昆虫视紫红质。我们通过基于反射光谱计算模型的显微分光光度测量和计算,估算了菜粉蝶视网膜中视紫红质的最大吸收波长值(λ-max)和相对密度(0.72,P530;0.12,P470;0.15,P360)。我们分离出了三个视蛋白编码cDNA片段,通过与特征明确的昆虫视紫红质家族进行同源性比较,确定它们分别对应P530、P470和P360。通过视蛋白mRNA原位杂交绘制了视网膜镶嵌图,发现就短波长视紫红质的表达模式而言,视网膜含有三种小眼。在一些小眼中,P360或P470在R1和R2相对的受体细胞中表达;在其他小眼中,一个细胞表达P360,而其对应的细胞表达P470。P530在所有小眼的其他七个细胞中表达。表达P470的细胞在腹侧视网膜中丰富,但在背侧几乎不存在。我们的结果表明,蛱蝶科和凤蝶科蝴蝶的色觉系统存在重大差异:蛱蝶科菜粉蝶的色觉系统比已研究的具有四色视觉的凤蝶科蝴蝶更简单,是三色视觉系统。