Polyphemus Moth

The Polyphemus Moth (Antheraea polyphemus) is one of North America's largest and most spectacular. People seeing it for the first time generally remark, "That's a moth? I didn't know moths were so big and pretty!" With a wingspan of up to 6 inches, the Polyphemus Moth is a member of the silk moth family. Adults do not have functional mouth parts and do not eat during their portion of the life cycle. Instead they emerge locally in large numbers around the same time of year, when they live for less than a week and their only purpose is to mate (and in the case of females, lay eggs).

Adult moths have large eyespots, which they use to scare off predators. From a distance, these spots look like the eyes of a much bigger creature, causing many predators to head off in another direction. When you look closely at the eyespots, you'll notice that the center seems clear. In this area of the wing, there are no wing scales attached to the clear wing membrane, leaving it visible. In this microscope image, you can also see one of the veins that run through the wing, giving it support and structure.

You can tell male and female Polyphemus moths apart by their antennae. Females, like the one shown in the photo at the top of the post, have smaller antennae. Males, by contrast, have large feathery antennae, the better for picking up the scent of nearby females for mating.

Mating occurs at night, often in the early evening hours. Females lay eggs singly or in small groups. If host plants are available (oak, willow, maple, birch, wax myrtle), they will lay eggs on the leaves. If no host plant is available, females deposit their eggs anywhere, in the hopes that the larvae may be able to crawl to food. The eggs are very hard, and can take several weeks to hatch.

Polyphemus Moth caterpillars are bright green. When very small, their tubercles topped with stiff spiny hairs are more obvious. These caterpillars are harmless to humans, though their size in 5th instar just before they pupate can be a little alarming (as thick as your thumb and up to 4 inches long). Because the adult moth will not eat, it must store up large fat reserves during its caterpillar stage to sustain it.

2nd Instar

5th Instar

Like other moths, Polyphemus Moths make a cocoon for pupation. They spin these using silk, incorporating nearby leaves and twigs. The silk dries quite hard, creating a protective case for the pupating caterpillar inside. Polyphemus Moths can spend months in cocoon, especially up north where they only have one generation each year. In Florida, they seem to spend about 4-6 weeks or so in cocoon on average.

What's in a Name? The species epithet polyphemus comes from the giant eyespot on each lower wing. In Greek mythology, Polyphemus was a cyclops, a one-eyed giant, and was the son of Poseidon and Thoosa. The name "Polyphemus" itself meant "abounding in songs and legends."