Spicebush swallowtail caterpillar is master of disguise

If there is one critter in the animal kingdom that stakes claim as being the master of disguise, it's the spicebush swallowtail caterpillar. And talk about having a bag of tricks up its sleeve with some of the most ingenious gadgets of camouflage and mimicry.

This amazing little fellow never ceases to amaze me, and once again it held true to its grandeur.

A few days ago, I had visited Todd Price Nursery near Canadensis to purchase some native wildflowers.

After chatting with Operations Manager, Peggy Chirico, about wildflowers our discussion somehow changed from showy blossoms to a small native tree called spicebush.

Peggy said that spicebush is quite common at the nursery, especially along the Brodhead Creek.

I concurred and informed Peggy that spicebush is one of the dominant understory trees along the Susquehanna River, where I live in Luzerne County.

On the way out of the nursery, I noticed a stand of spicebush growing along the bank of the Brodhead Creek.

Going on a hunch, I pulled alongside the dirt road and walked toward the stand of spicebush to test my visual acuity in an attempt to find a spicebush swallowtail caterpillar.

Based upon past experience, it is best to search the upper branches, as the tiny caterpillars seem to have a preference to feed upon the tender new-growth leaves.

After 15 minutes of pulling down high branch tips and diligently searching for larvae amongst the leaves, I was about to give up, until I discovered a freshly coiled spicebush leaf.

This is a good indicator that a spicebush caterpillar was hiding inside as it often seals itself inside the coiled leaf with silk.

"You can't fool me," I boasted, while confidently uncoiling the sticky leaf to unveil the hidden caterpillar.

Empty? I questioned the outcome and widened the leaf between my thumbs and searched once again. Same result and same outcome. I knew there was a spicebush caterpillar nearby so, I kept on searching.

Just before I was about ready to grab another and let go of the branch tip I was holding previously, I saw two tiny, life-like eyeballs staring right at me.

"How in the world did I overlook you?" I pondered.

Well, Mother Nature says I'm supposed to as this little fellow is the master of camouflage and mimicry.

Less than one-half inch in length the little caterpillar did a good job in concealment by attaching itself onto an adjacent leaf stem.

The lime green coloration of its slender body blended remarkably with the greenish stem of the spicebush leaf.

It would have remained invisible but, I was very fortunate to face it "eye-to-eye" as its peculiar-looking fake eyes located near the upper section of its body was a dead give away to me but, to a surprised ravenous bird, those large fake eye balls look quite intimidating.

Being a vulnerable caterpillar living in a world of hungry predators, Mother Nature has designed the spicebush caterpillar to perfection.

I say "designed" in not a singular sense of description but, in transformations of weird and unusual variations throughout stages of its development, from larva to butterfly. As mentioned earlier, this amazing caterpillar is a master of camouflage and mimicry, and before I lose sight of it, let's explore all of its illusion.

There are many animals, especially insects that exhibit spectacular examples of camouflage. However, the spicebush swallowtail caterpillar demonstrates the art of camouflage and mimicry throughout all stages of its life in the most fascinating illustrations.

Bird Dropping Mimic

Let's begin with its earliest stage of life after hatching from an egg in which the mother spicebush swallowtail butterfly undoubtedly laid her upon a green leaf of her host plant such as spicebush or sassafras.

Caterpillar larvae typically go through 4 to 5 instars or molts, in which they grow out of their old skin before forming a chrysalis. The newly hatched larvae and early instars of the spicebush caterpillar has body colorations that are mottled dark brown and white and remarkably resembles a bird dropping. What better defense is there than to mimic bird poop?

Snake Head Mimic

Upon its final instar, the caterpillar grow much larger and transforms from a bird dropping mimic into a leafy green creature with two life-like eye balls on top of its thorax, which amazingly resembles the head of a green snake.

Many species of vulnerable caterpillars are nocturnal feeders to avoid conflicts with daytime feeding birds. So during the day the spicebush caterpillar often hides inside a leaf aided by sticking silk, which transforms the broad leaf into a green sleeping blanket.

The caterpillar positions itself vertically with its head facing up. If by chance a bird or other predator peeks inside the leaf and sees two big snake eyes staring right back at them, they must quickly decide if it's an optical illusion or the real deal?

I have seen spicebush caterpillar in the snake-eye stage move about leaves and stems and quite frankly become mesmerized at the comical expression of the fake eye spots. Sometimes the caterpillar lifts its head upward which really mimics a snake.

The fake eyes are precisely marked and colored with black eye rings, yellow eyelids, black pupils and even with a dab of white, which gives the eyeball a wet sheen look.

Snake Tongue Mimic

If that artistic mimicry somehow does not fool the predator, the spicebush caterpillar as well as the black swallowtail caterpillar has another trick up its sleeve, or in this case, up inside its head. If threatened, the caterpillar can project out from the head its osmeterium, which mimics the forked tongue of a snake.

Not only does it mimic a snake tongue but, it is brightly colored yellow, which is a warning color. As an added deterrent, the osmeterium gives off an foul-scented odor, which might discourage predators. I have tried many times to capture a photo of this bizarre form of mimicry but, the only successful photo was that of the black swallowtail caterpillar.

Dead Leaf Mimic

The final caterpillar stage is the formation of a chrysalis, in which the caterpillar securely attaches the head of its body with a line of silk to a leaf, limb or branch. At first the newly formed chrysalis is leafy green in color and very hard to detect but, afterwards its turns light brown resembling the color of a dead leaf and the perfect camouflage for the over-wintering chrysalis.

Pipevine Swallowtail Mimic

When the caterpillar transforms into the adult stage called the spicebush swallowtail butterfly, it too has to avoid being consumed by predators. The butterfly is no longer leafy green in color but beautifully iridescent. The body of the butterfly is black with aqua blue wings. In some degree of mimicry protection the butterfly exhibits rows of orange spots on the underside of the hind wings and a row of white spots on the upper side of the hind wings. These bright contrasting colors with small eyes spots might scare would-be predators but, its best defense is that the spicebush swallowtail butterfly mimics the color and patterns of the poisonous pipevine swallowtail butterfly.

So, now you learned the magic show of the spicebush swallowtail and all of its illusional glory. It is one of nature's finest fakers being a master of mimicry, commander of camouflage, denizen of disguise and best yet, a stage full of comical deception. One moment it's a turd from a bird, and another time it'll gamble and roll a pair of snake eyes. Don't listen to its rhetoric as its speaks with a forked tongue but, it really does have bad breath. It sleeps on a leaf of a different color and, when its awakens it wears an iridescent evening dress full of poison and terror. But, we really know it's all synonyms and spice and everything nice