Ilia Underwing

Catocala ilia — the Ilia underwing — is one of about 250 species in genus Catocala (the underwing moths) and one of the most striking groups of moths in NA Lepidoptera. The species is widespread across all of eastern North America from southern Canada south through the eastern US to Texas. Adults are 6-9 cm wingspan, with the species' two diagnostic wing-pattern features. The FOREWINGS are intricately patterned in gray, white, and black bands and irregular markings that exactly resemble TREE BARK — the species and most other Catocala underwings are essentially INVISIBLE against tree trunks of oak, hickory, and other deciduous host trees, providing nearly perfect cryptic camouflage when the moth is at rest with wings folded over the back. The HINDWINGS, hidden when at rest, are dramatically colored: Catocala ilia has stunning ORANGE-AND-BLACK BANDED hindwings with two black bands on a bright orange ground color. Different Catocala species have different hindwing colors: red, orange, yellow, white, pink, and combinations are all represented across the 250+ NA species, making genus Catocala one of the most visually diverse Lepidopteran groups in NA. The species is one of the most-cited examples of FLASH COLORATION in NA Lepidoptera. At rest with wings folded over the back, underwing moths are essentially invisible — birds and other predators that systematically search tree bark for prey items either miss the moths entirely or fail to recognize them as edible. When the moth is touched, jostled, or otherwise threatened, it RAPIDLY OPENS THE WINGS to expose the brilliant hindwings — the sudden color contrast STARTLES THE PREDATOR (causing hesitation, retreat, or attack confusion), and the moth flies away to a new perch. The flash-and-startle defense is one of the most-cited examples in modern textbook discussions of insect anti-predator defense. Genus Catocala is one of the most-collected groups of moths by amateur lepidopterists because of the dramatic hindwing color diversity — different species are valued for their unique color patterns, and many populations contain regional COLOR VARIATIONS that further increase collection interest. Larvae are slender brown-gray caterpillars that feed on deciduous tree leaves (especially oak and hickory) and are themselves bark-camouflaged when at rest on host trees. The species is harmless to humans and one of the most-photographed moth groups in eastern NA macro nature photography.