Ecology and Evolutionary Biology, School of Biosciences, University of Sheffield, Alfred Denny Building, Western bank, Sheffield, S10 2TN, UK.
Department of Physics and Astronomy, University of Sheffield, Hicks Building, Hounsfield Road, Sheffield, S3 7RH, UK.
Nat Commun. 2024 May 20;15(1):4073. doi: 10.1038/s41467-024-48060-3.
Vivid structural colours in butterflies are caused by photonic nanostructures scattering light. Structural colours evolved for numerous biological signalling functions and have important technological applications. Optically, such structures are well understood, however insight into their development in vivo remains scarce. We show that actin is intimately involved in structural colour formation in butterfly wing scales. Using comparisons between iridescent (structurally coloured) and non-iridescent scales in adult and developing H. sara, we show that iridescent scales have more densely packed actin bundles leading to an increased density of reflective ridges. Super-resolution microscopy across three distantly related butterfly species reveals that actin is repeatedly re-arranged during scale development and crucially when the optical nanostructures are forming. Furthermore, actin perturbation experiments at these later developmental stages resulted in near total loss of structural colour in H. sara. Overall, this shows that actin plays a vital and direct templating role during structural colour formation in butterfly scales, providing ridge patterning mechanisms that are likely universal across lepidoptera.
蝴蝶生动的结构色是由光子纳米结构散射光引起的。结构色是为了许多生物信号功能而进化的，具有重要的技术应用。从光学角度来看，这些结构已经得到了很好的理解，然而，对它们在体内的发育过程的了解仍然很少。我们表明，肌动蛋白在蝴蝶翅膀鳞片的结构色形成中起着密切的作用。通过比较成年和发育中的 H. sara 的彩虹色（结构色）和非彩虹色鳞片，我们表明彩虹色鳞片具有更密集的肌动蛋白束，导致反射脊的密度增加。在三个远缘蝴蝶物种中的超分辨率显微镜显示，肌动蛋白在鳞片发育过程中，特别是在光学纳米结构形成时，会反复重新排列。此外，在这些较晚的发育阶段进行肌动蛋白扰动实验，导致 H. sara 的结构色几乎完全丧失。总的来说，这表明肌动蛋白在蝴蝶鳞片的结构色形成过程中起着至关重要的直接模板作用，提供了可能在鳞翅目动物中普遍存在的脊模式形成机制。
