"Invisible Wings" Revealed: How Transparent Patches Help Butterflies and Moths Defend Predators

A study published today in the journal eLife showed that partially transparent wing patches not only hide butterflies and moths, but also warn predators not to disturb them
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This discovery reveals how some butterflies and moths with partially transparent wings have evolved to mimic other species that already have this characteristic

Despite their delicate appearance, butterflies and moths have many defenses
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They may use camouflage or transparent patches on their wings to avoid the attention of predators, or they may use bright contrasting colors to warn predators that they are poisonous or unpalatable

“We started to explore the structure and optical characteristics of transparent patches of different species, which also have warning colors,” said lead author Charline Pinna, who is a member of the Muséum National Museum of Natural History (national d'histoire naturrelle, Sorbonne Université) PhD student
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"By doing this, we hope to determine how butterflies and moths evolve these defenses, and how bird predators perceive them

Pinna and her colleagues used a method called spectrophotometry to measure the transmittance of light through transparent patches on 62 butterfly wings
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Then, they used computer modeling to determine whether these transparent patches looked similar to their mimics in the eyes of bird predators

Next, the research team used digital microscopes and scanning electron microscopes to examine the tiny structures on the transparent patches
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This is to help researchers understand how the insect's wings produce transparency-under normal circumstances, the wings are completely covered with colored scales

The author also pointed out that for species that mainly live in humid tropical regions, transparent patches may not be as waterproof as opaque wing patches
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Another potential price is the insect's ability to regulate body temperature

"Our findings indicate that species with transparent wing patches can benefit from double protection from predators," concludes Marianne Elias, who is the National Museum of Natural History (national d'histoire) in the Muséum.
naturrelle, a senior researcher at Sorbonne Université, and Doris Gomez (Doris Gomez) are the senior authors of this study
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"At a distance, transparent spots may make butterflies and moths more difficult to see by predators, but when viewed at close range, their warning color patterns may also remind predators not to disturb them