Invertebrates
Promethea Moth
Callosamia promethea · also called promethea moths, spicebush silkmoth
A dark moth glides through the forest canopy in broad daylight, moving with the unmistakable flutter of a toxic swallowtail butterfly, and only a closer look reveals it is actually a male promethea moth, borrowing a butterfly’s reputation to survive.
Overview
The promethea moth, Callosamia promethea, is a distinctive giant silk moth native to forest habitat across the eastern United States and southeastern Canada. Its unusual daytime-flying, butterfly-mimicking males, dusk-active pheromone-releasing females, and cleverly camouflaged overwintering cocoon make it one of the more behaviourally striking moths in eastern North America.
Two moths in one species
Few moths show as sharp a split between the sexes as the promethea, with males flying by day disguised as a toxic butterfly and females waiting for darkness to call in mates with scent alone.
Status
Least Concern — widespread and common across suitable forest habitat throughout eastern North America.
Promethea Moth: common questions
Why does the male promethea moth fly during the day?
A male promethea moth is unusual among giant silk moths for flying during daylight hours, and its dark colouration closely resembles the foul-tasting pipevine swallowtail butterfly, a resemblance that likely offers the moth some protection from predators that have learned to avoid that toxic butterfly's pattern.
How is the female promethea moth different from the male?
The female promethea moth is paler and more reddish-tan than the dark male, and rather than flying by day, she waits until dusk to release powerful pheromones into the air, a scent that males can detect and follow from a considerable distance to find a mate.
How does a promethea moth protect its cocoon over winter?
A promethea moth caterpillar spins its cocoon inside a leaf that it curls and secures to a twig with silk, effectively camouflaging the cocoon among the tree's own dried, unshed foliage, where it remains dormant through the cold winter months until spring.
What plants does the promethea moth caterpillar eat?
The promethea moth caterpillar feeds on the leaves of several specific host plants, most notably spicebush, sassafras, tulip tree, and wild cherry, and adult moths do not feed at all, surviving entirely on fat reserves stored during the caterpillar stage.