Carnegie Museum of Natural History

One of the Four Carnegie Museums of Pittsburgh

Poisons of the Carnegie: Io Moth

Female Io moth
Female Io moth

 

Male Io moth
Male Io moth

 

by Vanessa Verdecia

The Io moth (Automeris io) is in the subfamily Hemileucinae, which belongs in the family called Saturniidae—the Giant Silkworm Moths. Caterpillars in the hemileucine subfamily have urticating spines that are filled with poison. There are many
different species in this group, some more toxic than others.

The Io moth occurs here in Pennsylvania as well as other parts of the eastern United States. The last instar of the caterpillar is green and has a red and white stripe down the side as seen in the image below.

instar of the caterpillar of an Io moth

The caterpillar is covered in spines that can break off and embed themselves in one’s skin if it is handled. The broken spines cause an irritation on the skin that can last for some time after the sting. Seen above are pictures of the adult male and female moths from the Carnegie collection. The female moth has a wingspan of about 8 centimeters and is reddish-brown in appearance, while the male has yellow wings and is a little smaller. They both have eyespots on the hindwings which serve as a
defense mechanism against predators, such as birds, that might confuse them for an animal looking back at them.

This summer is all about poison at Carnegie Museum of Natural History. Staff will be sharing fascinating pieces of our collection that are toxic, poisonous, or venomous to celebrate our summer blockbuster exhibition The Power of Poison. For more information about this highly interactive, family-friendly exhibition, visit pop.carnegiemnh.org.