Hickory Horned Devil Caterpillars: Ferocious Looking, but Harmless
Nothing to Fear
Wow! Hickory horned devil caterpillars have really got their bluff in on everyone, including chickens that normally eat caterpillars! They are huge and look like they could swallow a mouse for lunch, but although their looks scream "get away...run," they are just some big, old harmless babies that wouldn't hurt a flea. They are usually about 5-6 inches long, so you can see why a chicken might be a little nervous tackling one of them.
This big, ugly sucker, however, will eventually turn into a large, colorful regal (or royal walnut) moth.
Even those scary, long red horns with black tips don't sting; it's all a ruse. These bright green caterpillars are actually pretty easy to handle, so when you see one, go ahead and pick him up, you'll be just fine.
They Burrow Instead of Spin
The hickory horned devil caterpillar differs from most other caterpillars that spin a cocoon. Instead, they actually burrow down into the ground to transform into an adult moth. In fact, you are unlikely to see one of these caterpillars until he climbs down out of a tree looking for a site for pupation. If you do see one of them on the pavement or any other area where burrowing would be difficult, you can help it out by picking it up and moving it to an area where the soil is soft enough for burrowing.
Did We Mention That They Are Large?
Hickory Horned Devils Love Shade Trees
Some of the trees these caterpillars like to hang out in include hickory, ash, persimmon, sweetgum, sycamore and walnut. And, even though a hickory horned devil caterpillar will eat the leaves of shade trees, usually the damage is minimal because their numbers are small.
When regal moths emerge from the soil during the summer, they mate and a female moth will spend most of her remaining life laying eggs, depositing them on leaves in clusters. It takes the eggs about 15-16 days to hatch, starting the four larval stages - embryo, larva, pupa and imago. In the final stages, these caterpillars have voracious appetites.
If you disturb a hickory horned devil caterpillar, it will throw its body from side to side trying to scare you away, but it is all an act and they really are harmless. In late summer to early fall, the caterpillar will burrow into the soil to pupate and overwinter. Most will remain as pupae for a little less than a year, although others take almost two years to turn into moths.
Populations of these caterpillars appear to be declining and they are generally not considered a pest. They can survive a very moderate frost and will continue to feed as it gets warmer, but because there are so few of them, no pest control is recommended.
In case you wondered about the taxonomic rank of the hickory horned devil caterpillar:
- Kingdom: Animalia
- Phylum: Arthropoda
- Subphylum: Atelocerata
- Class: Hexapoda (including Insecta)
- Infraclass: Neoptera
- Subclass: Pterygota
- Order: Lepidoptera
- Superfamily: Bombycoidea
- Family: Saturniidae
- Subfamily: Ceratocampinae
- Genus: Citheronia
- Subject: Citheronia regalis (Fabricius)
These Are Some Great Sites on the Subject
- The Hickory Horned Devil From Egg to Caterpillar
An online resource devoted to North American insects, spiders and their kin, offering identification, images, and information. Using photographs, this article shows the hickory horned devil changing from egg to caterpillar.
- The Hickory Horned Devil, a Fierce but Harmless Caterpillar
Kidsdiscover.com introduces children to the hickory horned devil caterpillars, which look fierce and can be almost as big as a hot dog, but are harmless.
- The Regal Moth or Hickory Horned Devil Caterpillar
The University of Florida has a great site on the Hickory Horned Devil caterpillar, as one of their featured creatures.
Questions & Answers
© 2017 Mike and Dorothy McKenney