Head to head
Imperial Moth vs Regal Moth
An imperial moth and a regal moth are both enormous members of the giant silk moth family found in eastern North American forests, each famous less for the adult moth itself than for an extraordinary caterpillar stage.
| Imperial Moth | Regal Moth | |
|---|---|---|
| Scientific name | Eacles imperialis | Citheronia regalis |
| Caterpillar strategy | Extreme colour variation between individuals | Intimidating spines, harmless bluff |
| Caterpillar nickname | None widely used | Hickory horned devil |
| Adult wing colour | Yellow with purple-brown patches | Orange and grey |
| Adult feeding | Does not feed | Does not feed |
| Pupation | Underground, no cocoon | Underground, no cocoon |
| Host plants | Oak, maple, pine, sweetgum, and more | Hickory, walnut, and related trees |
| Conservation status | Least Concern | Least Concern |
Imperial Moth vs Regal Moth: common questions
Which caterpillar is more dangerous, the imperial moth's or the regal moth's?
Neither is actually dangerous; the regal moth's hickory horned devil caterpillar looks the more intimidating of the two thanks to its large size and curved spines, but it is entirely harmless and relies purely on that fearsome appearance to bluff predators, while the imperial moth's caterpillar relies instead on dramatic colour variation between individuals to make it harder for predators to form a consistent search image.
Why don't the adult imperial moth or regal moth eat anything?
Both species lack functional feeding mouthparts as adults, a trait shared across much of the giant silk moth family, so each survives for only a brief period, roughly a week or two, purely on fat reserves built up during the much longer caterpillar stage, with that short adult life focused entirely on finding a mate before dying.
How can you tell an imperial moth from a regal moth?
Look at the wing colour and pattern: the imperial moth displays broad yellow wings marked with variable purple-brown patches, while the regal moth shows a more orange-and-grey pattern and is generally the larger of the two species by wingspan, one of the biggest moths found anywhere in North America.