But since these gyroids are only a few hundred nanometers across, scientists had only captured the structures in fuzzy 2-D snapshots.
Now, thanks to an x-ray imaging technique, "we were able for the first time to unambiguously diagnose the 3-D structures of these complex materials," said study co-author Vinodkumar Saranathan, a biologist at Yale University.
"Evolutionarily speaking, each of these butterfly families have independently stumbled upon this," Saranathan said. "By using these butterflies as templates, we could reproduce [the gyroids] for artificial technological purposes."
For example, gyroids could be used to produce fade-resistant fabrics that don't require pigments and are visible from all directions.
Emerald-patched Cattleheart Butterfly
The green patches on an emerald-patched Cattleheart butterfly (pictured) are the result of gyroids embedded in the wing scales.
"The green color is very similar to the leaves [in the butterfly's environment], so we think it helps with camouflage," study co-author Saranathan said.
Scientists think the gyroids only form during the butterflies' cocoon phase, and can't be replaced once the adult insects emerge from their cases.