UV wing patterns in saturniid moths: diversity and mechanisms

Ultraviolet wing patterns are commonly used for intra- and inter-species communication in butterflies. However, as moths have distinct wing resting positions and crepuscular or nocturnal lifestyles, findings in butterflies might not be generalizable to all Lepidoptera. Here, we investigated the location, size and UV reflectance of wing patterns in both sexes of three species of saturniid moths using UV photography. We also investigated the UV reflection mechanisms at the level of individual scales using microspectrophotometry and focused-ion beam scanning electron microscopy. We found that female wings are more UV reflective than male wings and ventral surfaces are more reflective than dorsal surfaces, which is the opposite of what is generally seen in butterflies. The same trend was observed for UV area with an expansion of size in females and ventral wing surfaces. The mechanisms of UV reflection, however, seem to be conserved between saturniid moths and nymphalid butterflies, but not pierids.