史前素描的爱好者们现在可以用更少的猜测为自己喜爱的古昆虫填色了。
从甲虫到蝴蝶的现代昆虫因为它们的金属色调而闻名于世。这些复杂且斑斓的色彩模式起源于沿着生物外骨骼外层的细微结构发生的调整，例如超薄组织的交互层向不同方向发出的反射光。
许多甲虫化石也具有类似的色彩，但是科学家们无法确定的是石化过程是否会改变它们的色彩。
为了解开这道关于颜色的难题，美国耶鲁大学的古生物学家Maria E. McNamara和同事在显微镜下对古老昆虫——距今约1500万年到5000万年——的纳米结构进行了分析。
果然，结果显示，与它们的外骨骼结构所表现的颜色相比，许多甲虫具有不同的颜色。研究小组在本周的英国《皇家学会学报B》网络版上报告了这一研究成果。
研究人员断定，石化过程中的分子变化很可能将甲虫的颜色向着彩色光谱的红色端推进，例如，一只通常为黄色的甲虫会变为橙色。（生物谷 Bioon.com）
doi:10.1098/rspb.2011.1677
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The original colours of fossil beetles
McNamara, Maria E.; Briggs, Derek E. G.; Orr, Patrick J.; Noh, Heeso; Cao, Hui
Structural colours, the most intense, reflective and pure colours in nature, are generated when light is scattered by complexnanostructures. Metallic structural colours are widespread among modern insects and can be preserved in their fossil counterparts,but it is unclear whether the colours have been altered during fossilization, and whether the absence of colours is alwaysreal. To resolve these issues, we investigated fossil beetles from five Cenozoic biotas. Metallic colours in these specimensare generated by an epicuticular multi-layer reflector; the fidelity of its preservation correlates with that of other keycuticular ultrastructures. Where these other ultrastructures are well preserved in non-metallic fossil specimens, we can inferthat the original cuticle lacked a multi-layer reflector; its absence in the fossil is not a preservational artefact. Reconstructionsof the original colours of the fossils based on the structure of the multi-layer reflector show that the preserved coloursare offset systematically to longer wavelengths; this probably reflects alteration of the refractive index of the epicuticleduring fossilization. These findings will allow the former presence, and original hue, of metallic structural colours to beidentified in diverse fossil insects, thus providing critical evidence of the evolution of structural colour in this group.
