Can butterfly colors be preserved in resin? What I learned about embedding insects with wing scales
When butterfly or moth specimens are embedded in resin,the shape of the wings and the three-dimensional feel of the body remain within the transparent block. When light passes through, they look different from dried specimens, making them attractive as both artworks and specimens.
However, there is one difficult point with butterflies and moths.
It is that there are "scales" on the surface of the wings.
In conclusion, insects with scales like butterflies and moths can be embedded in resin. However, "encasing the shape" and "preserving the wing color and powdery texture as they are" are separate issues. By putting them in resin, yellows and whites may become transparent, blue-green luster may dull, or the scales may flow.
In other words, resin embedding is not just preservation, but a small experiment to see the compatibility between the specimen and the transparent resin.
Scales are the "color surface" of a butterfly
The wings of butterflies and moths are not colored by the thin membrane itself. The surface of the wings is densely lined with tiny scale-like structures called scales.
These scales can be broadly divided into two ways of appearing colored.
One is color due to pigments. Black, brown, yellow, red, and orange colors can be heavily influenced by pigments.
The other is structural color. Some colors like blue, green, and metallic luster are visible because the fine structures within the scales reflect light. In this case, the color is created by "how light bounces" rather than the "color of the material".
This is important for resin embedding. Structural color is based on the premise of being visible in the air. When resin enters, the path of light changes. As a result, colors that were vivid in dried specimens may become dark or look like different colors in resin.
Research that actually embedded butterflies in epoxy resin
In 2026, a Chinese research group embedded adult butterflies in five types of epoxy resin and compared them [Wu, 2026, Anhui Agric Sci Bull] DOI: 10.16377/j.cnki.issn1007-7731.2026.05.023.
In this study, dried *Papilio xuthus* (Asian swallowtail) and others were placed in silicone molds, a bottom layer of resin was created, the specimens were placed, and then the top layer was poured to embed them. As a result, partial dissolution and discoloration of wing scales were reported in all epoxy resins tested.
What is particularly easy to understand is that the way changes appear differs depending on the color. While black patterns were relatively easy to preserve, transparency was noticeable in yellow parts. In other butterflies, cases where orange-yellow markings changed significantly have also been reported.
Why does structural color change?
A helpful reference for considering why structural color changes is the 2024 study by Jessop et al. [Jessop, 2024, J R Soc Interface] DOI: 10.1098/rsif.2024.0185.
In this study, the green scales of a butterfly called Erora opisena were immersed in liquids with different refractive indices, and their reflection spectra were examined. The results showed that the reflection that appeared green in air became weaker in liquid, and the peak wavelength shifted toward the longer wavelength side.
This is not an experiment using epoxy resin itself. However, it serves as a basis for considering why the structural color seen in air changes when resin enters the microscopic gaps of the scales.
“Drying” and “pouring in thin layers” are fundamental
In guides for resin embedding of natural history specimens, it is stated that it is important that the specimen be dried or freeze-dried [Pajak, 2009, NatSCA News]. If moisture remains, it can cause cloudiness, bubbles, decay, and curing failure.
Also, resin generates heat when it cures. If you pour it too thick at once, the specimen may be damaged by heat, or air bubbles may become difficult to remove. For large specimens or those with thin wings, it is safer to layer thin coats.
Protocols for resin embedding of arthropod specimens for education also use a step-by-step method of creating a first layer, placing the specimen, and pouring the upper layer [Bejcek, 2018, J Insect Sci] DOI: 10.1093/jisesa/iey030, [Garza, 2026, J Vis Exp] DOI: 10.3791/69206.
However, it has been pointed out that for delicate insects with scales like mosquitoes, scales and legs are easily lost during casting. For butterflies and moths as well, it is necessary to handle them by not touching the wing surfaces directly, not applying the resin flow directly, and determining the posture from the body side.
Do not use coating agents on actual specimens right away
You might think that to protect the scales, you should spray them with varnish or a fixative before embedding.
However, this should not be done immediately on the actual specimen. This is because the coating agent itself can wet the scales, change their refractive index, and alter their color.
If you are going to try it, always compare it using damaged wings or surplus specimens. Divide the conditions into small groups such as “untreated,” “thinly coated,” and “different resin,” and photograph them before and after embedding under the same light.
The VITA CAST approach
Resin specimens made with VITA CAST do not just trap living things in a transparent material. The appearance of the specimen changes slightly in the light.
That change should not be viewed only as a failure. Sometimes, a sense of transparency and depth that was not visible in the dried specimen emerges. On the other hand, the powdery texture and vivid structural color that the dried specimen had may be lost.
Therefore, in resin embedding, you must first decide “what you want to preserve.”
Shape? Color? Structure? Or do you prioritize transparency as a work of art?
Once this goal is determined, the choice of specimen, type of resin, thickness of casting, and method of image recording will change.
Safety
Uncured epoxy resin and hardeners can cause dermatitis, sensitization, and respiratory irritation. When working, read the product's SDS and follow basic safety protocols: ensure ventilation, wear nitrile gloves, protective eyewear, and long sleeves. Keep materials away from food and living spaces, and place them in a location where they will not be touched while curing.
Also, resin embedding is irreversible. It is best not to embed research specimens, type specimens, specimens important for collection records, or individuals that are difficult to reacquire. Distinguish between specimens that should be preserved for museum collections and those that can be embedded for artistic or educational purposes.
Summary
Butterflies and moths can be embedded in resin.
However, for insects with wing scales, you must design your project with the understanding that the color and texture of the wings will change. While black patterns may remain visible, yellow and white colors tend to become transparent, and the structural colors of blue and green are likely to change in appearance within the resin.
The most important thing is not to use a valuable specimen for your first attempt. Create small test pieces. Take photos before and after embedding. Observe the compatibility between the resin and the specimen.
Resin embedding is not just a preservation process; it is an exercise in observing how the structures of living things are re-perceived within a transparent medium.
References and Image Sources
[Wu, 2026, Anhui Agric Sci Bull] Wu Mingxuan, Jin Feng, Yang Nana. Effects of different epoxy resins on the embedding effects of adult butterfly specimens. Anhui Agricultural Science Bulletin. 2026;32(5):100-103. DOI: 10.16377/j.cnki.issn1007-7731.2026.05.023
[Jessop, 2024, J R Soc Interface] Jessop AL, Pirih P, Wang L, Patel NH, Clode PL, Schroder-Turk GE, Wilts BD. Elucidating nanostructural organization and photonic properties of butterfly wing scales using hyperspectral microscopy. Journal of the Royal Society Interface. 2024;21(218):20240185. DOI: 10.1098/rsif.2024.0185
[Pajak, 2009, NatSCA News] Pajak M. Guide to Resin Embedding of Natural History Handling Specimens. NatSCA News. 2009;(17):68-74. No DOI. PDF: NatSCA News Issue 17
[Bejcek, 2018, J Insect Sci] Bejcek DA, Curtis-Robles R, Riley M, Hamer GL. Clear Resin Casting of Arthropods of Medical Importance for Use in Educational and Outreach Activities. Journal of Insect Science. 2018;18(2):34. DOI: 10.1093/jisesa/iey030
[Garza, 2026, J Vis Exp] Garza M, Curtis-Robles R, Sittenauer S, Hamer GL. Clear Resin Casting of Arthropods for Use in Education, Outreach, and Research. Journal of Visualized Experiments. 2026. DOI: 10.3791/69206
[Vukusic, 2009, J R Soc Interface] Vukusic P, Stavenga DG. Physical methods for investigating structural colours in biological systems. Journal of the Royal Society Interface. 2009;6 Suppl 2:S133-S148. DOI: 10.1098/rsif.2008.0386.focus
[Pérez Goodwyn, 2009, Naturwissenschaften] Pérez Goodwyn P, Maezono Y, Hosoda N, Fujisaki K. Waterproof and translucent wings at the same time: problems and solutions in butterflies. Naturwissenschaften. 2009. DOI: 10.1007/s00114-009-0531-z
*The figure from Jessop et al. 2024 is used under CC BY 4.0. Other cited paper data belongs to the respective authors. This article is intended for educational purposes, and there is no intent to infringe on copyright. The VITA CAST photos and the tables in this article are creations of VITA CAST.