The Polyphemus moth (Antheraea polyphemus) is a large North American silk moth. It is widely distributed across southern Canada, much of the United States, and Mexico. This moth has a wingspan of 10 to 15 centimeters (approximately 4 to 6 inches). Its coloring typically ranges from reddish to yellowish brown, and its body is covered in fine hairs.
The Polyphemus moth is known for the purplish eyespots on its hindwings. These eyespots inspired the moth’s name, referencing the one-eyed giant Polyphemus from Greek mythology. These moths commonly reside in deciduous hardwood forests, orchards, urban areas, and wetlands.
The Caterpillar’s Feast
The Polyphemus caterpillar is a voracious eater. As herbivores, they consume large quantities of plant material to fuel rapid growth and accumulate energy reserves. A newly hatched caterpillar will even eat its own eggshell before beginning to feed on plant leaves. These caterpillars grow significantly, reaching lengths of up to 7.5 centimeters (around 3 inches) before they are fully developed. They can consume 86,000 times their initial body weight in less than two months.
Polyphemus caterpillars are polyphagous, meaning their diet includes a wide variety of host plants. Common trees and shrubs they feed on include:
- Oak
- Maple
- Birch
- Willow
- Elm
- Apple
- Cherry
- Alder
- Chestnut
- Hickory
- Rose
- Basswood
- Ash
- Dogwood
- Hazel
- Walnut
- Beech
- Honey locust
- Pear
- Sassafras
- Sweetgum
- Sumac
These caterpillars are bright green, often with small red and silver spots or orange tubercles. They are solitary feeders, remaining on their chosen host plants throughout their development. Once fully grown, they spin a silk cocoon, often incorporating leaves, either on the host tree or among leaf litter on the ground.
The Adult Moth’s Fast
Adult Polyphemus moths do not feed at all. They possess vestigial, or non-functional, mouthparts, rendering them unable to consume food. The sole purpose of the adult moth is reproduction, and they rely entirely on the energy reserves accumulated during their caterpillar stage. This non-feeding nature contributes to their short adult lifespan, which typically ranges from 7 to 15 days.
Adult Polyphemus moths are nocturnal, becoming active after dusk. The males have large, feathery antennae that are highly sensitive, allowing them to detect pheromones released by females from long distances. This enables them to locate mates efficiently within their brief adult lives. Females lay eggs shortly after mating, continuing the species’ life cycle. The short duration of the adult stage underscores the importance of the caterpillar’s extensive feeding period for the species’ survival.