Hierarchical woven fibrillar structures in developing single gyroids in butterflies

Area of Science:

• Biomaterials Science
• Nanotechnology
• Structural Biology

Background:

• Nature self-organizes complex nanomaterials with unique properties.
• Gyroid nanostructures, known for symmetry and topology, exist across biological kingdoms.
• In butterflies, gyroids act as photonic crystals, generating structural colors.

Purpose of the Study:

• To investigate the formation mechanism of gyroid nanostructures in butterfly wing scales.
• To challenge the assumption of smooth gyroid formation in nature.
• To understand the structural basis of color generation in *Parides sesostris*.

Main Methods:

• Ultramicroscopy of pupal tissue from *Parides sesostris*.
• Electron diffraction analysis of wing scale material.
• Comparative analysis of normal and surgically altered pupal development.

Main Results:

• Gyroid structures in *Parides sesostris* are composed of helical weavings of fibers.
• Absence of crystalline order was detected within the fibrillar gyroid material.
• Fibrillar structures were also observed in wing scales with altered pupal development, correlating with blue coloration.

Conclusions:

• Butterfly gyroids can form as woven fibrillar structures, not solely smooth constructs.
• The fibrillar nature and arrangement influence the optical properties, such as color.
• Findings offer insights into biological self-organization and bioinspired nanomaterial design.