Developmental, cellular, and biochemical basis of transparency in clearwing butterflies

The wings of butterflies and moths (Lepidoptera) are typically covered with thousands flat, overlapping scales that endow the colorful patterns. Yet, numerous species Lepidoptera have evolved highly transparent wings, which often possess altered morphology reduced size, presence membrane surface nanostructures dramatically reduce reflection. Optical properties anti-reflective been characterized for several ‘clearwing’ Lepidoptera, but developmental processes underlying wing transparency unknown. Here, we apply confocal electron microscopy to create a time-series in glasswing butterfly, Greta oto, comparing non-transparent regions. We find during early development, scale precursor cell density is regions, cytoskeletal organization growth differs between thin, bristle-like morphologies within regions round opaque Next, show on composed two layers: lower layer regularly arranged nipple-like nanostructures, an upper irregularly wax-based nanopillars predominantly long-chain n-alkanes. By chemically removing nanopillars, along optical spectroscopy analytical simulations, demonstrate their role generating properties. These findings provide insight into morphogenesis composition naturally organized micro- may bioinspiration new materials.