143: Io Moth
The Io moth, also known as the peacock moth, lives across a broad swath of North America, from southern Quebec and Ontario all the way to Utah. In Colorado they are found mainly along the Front Range and near Pueblo. They are in the family Saturniidae, who are some of the largest moths in the world, and many have “eyes” on their wings as the Io moth does. The name comes from Greek mythology – Io was one of Zeus’s lovers who he turned into a cow so his wife Hera wouldn’t find out about his philandering – but I could not find anything to tell me why this is their name aside from maybe a reference to their beauty.
These moths have strong sexual dimorphism, with the females being both larger and completely differently colored than the males. The females have a rust-brown coloration, while the males, like the one depicted below, are bright yellow. Both have a “startle response” designed to put off potential predators – if threatened, they will flash the “eyes” on their wings and duck their heads so they resemble owls, hopefully making small mammals or reptiles trying to predate them think twice.
When they are caterpillars, these animals have venomous spines along their body; after they transform into their adult moth forms, they do not eat, instead relying on food stored from their larval caterpillar stage. As a result, they have a short lifespan in which they are focused on mating and laying eggs. In Colorado, there is only one generation per year, but in warmer locations, they can produce two.
Vincent Van Gogh painted a Giant Peacock Moth, which is related to the Io Moth. Who did a better job?