Wednesday, June 8, 2011
The Polyphemus Moth
The Polyphemus Moth (Antheraea polyphemus) is a giant silk moth, with a wingspan reaching up to 6 inches (15 cm). This particular one had a wingspan of about 5 inches and has an injured right forewing. The moth is nocturnal, so it's possible the cause of the injury or the injury itself was the reason it was out during the daylight.
The distinctive purplish eyespots on the hindwings give it its name, from the Greek myth of the cyclops Polyphemus. This distractive pattern is a defense mechanism to protect itself against predators, probably through misdirection. Underneath, the wings look like dead leaves, which also deters predators.
It lays flat, light brown eggs on the leaves of its host plant. The eggs hatch into small yellow caterpillars that molt 5 times, with the 5th being into a pupa. In this 5th stage, the caterpillars are a bright green with yellow stripes and red and silver spots on their sides and can grow 3 to 4 inches long.
The caterpillars are vulnerable to predators including birds, small mammals and some predatory insects. One type of wasp is a parasite of the caterpillars. It injects eggs into the caterpillar where the larvae hatch and feed on the caterpillar's body.
When they emerge from the cocoon, typically in late May or early June, their purpose is to mate. Once mated, the female spends the remainder of her life laying eggs, while the male may mate several more times. Because they have reduced mouth parts, they do not eat and typically live for less than a week.
The Polyphemus is a very interesting moth, which I feel fortunate to have seen and photographed.