Molecular basis of wax-based color change and UV reflection in dragonflies.

Ryo Futahashi,Yuji Hirai,Takahiko Hariyama,Takema Fukatsu,Shunsuke Yajima,Yumi Yamahama,Genta Okude,Ryouka Kawahara-Miki,Kazutoshi Yoshitake,Naoki Mori,Migaku Kawaguchi,Daisuke Ishii

doi:10.7554/elife.43045

Abstract

Many animals change their body color for visual signaling and environmental adaptation. Some dragonflies show wax-based color change and ultraviolet (UV) reflection, but the biochemical properties underlying the phenomena are totally unknown. Here we investigated the UV-reflective abdominal wax of dragonflies, thereby identifying very long-chain methyl ketones and aldehydes as unique and major wax components. Little wax was detected on young adults, but dense wax secretion was found mainly on the dorsal abdomen of mature males of Orthetrum albistylum and O. melania, and pruinose wax secretion was identified on the ventral abdomen of mature females of O. albistylum and Sympetrum darwinianum. Comparative transcriptomics demonstrated drastic upregulation of the ELOVL17 gene, a member of the fatty acid elongase gene family, whose expression reflected the distribution of very long-chain methyl ketones. Synthetic 2-pentacosanone, the major component of dragonfly's wax, spontaneously formed light-scattering scale-like fine structures with strong UV reflection, suggesting its potential utility for biomimetics.

Highlights

Many organisms exhibit a variety of body color patterns for visual communication and environmental adaptation
UV reflection was hardly detected on the body surface of immature males and females (Figure 1B,D,G and I; Video 1)
As adult aging proceeded further, males and females developed pruinose wax on the entire body surface (Figure 1A), which resulted in considerable UV reflection even in females

Summary

Introduction

Many organisms exhibit a variety of body color patterns for visual communication and environmental adaptation. The diversity of the color patterns encompasses the ultraviolet (UV) range, reflecting the fact that many animals can detect UV light as well as green, blue and/or red light (Osorio and Vorobyev, 2008). UV reflection has been reported from numerous organisms and may be important for protection against UV-induced damage and for visual signaling This ability may protect them from some of the damaging effects of sunlight; materials with similar properties would have a range of uses, including as coatings on windows that protect our homes and furniture or as cosmetics that protect ourselves in the same way

Methods

Results

Conclusion