Pink Horn

It’s the horns of a dilemma, no question about it.

~Steven Jeffrey

Melissa needed a few caterpillars for a teacher workshop this week, so I went out the other night with our UV flashlight to scan the vegetation around the house. A reminder that many species of caterpillars glow under UV light at night, making them much easier to spot. It was slim pickings but I did see one sphinx moth larva (aka horn worm, due to the presence of a spike on the posterior end). It had just molted so I didn’t want to disturb it. Its size and behavior (feeding on the underside of a leaf) gave the impression of a Walnut Sphinx caterpillar, a species I have found several times in our yard. Plus, when I glanced at the host plant and saw the compound leaves, I assumed it was a hickory, one of the hosts of Walnut Sphinx larvae. I noted the location and headed inside, hoping the caterpillar would still be there in the morning.

A beautiful sphinx moth caterpillar on the underside of a leaf (click photos to enlarge)

When I went out the next day to retrieve it, I saw that the sapling was not a hickory, but an ash, and that the larva was not a Walnut Sphinx…but, what is it? I had not paid close attention to detail in the glow of the UV light and the pattern and colors were not yet evident in the freshly molted caterpillar. I took a few quick photos and went inside to search my well-worn copy of Wagner’s Caterpillars of Eastern North America. There are six species of horn worm larvae that feed on ash so it made the search a bit easier. None of the images matched the bold pinkish splotches along the sides of my caterpillar, but reading the descriptions helped me decide that this beauty is a Waved Sphinx caterpillar, Ceratomia undulosa. They are quite variable as larvae, with most being green overall, others pink and yellow, or some combination.

The black dots on the anal plate and the textured pink horn are diagnostic of a Waved Sphinx larva

But they all tend to have the textured pinkish horn and black dots on the anal plate (the hardened area on the top of the last abdominal segment). A quick search online ( showed the diversity of this species’ caterpillar colors and confirmed this variation for a Waved Sphinx larva. I am guessing this is a 4th instar, so it has some growing to do before its final stage. Just goes to show, never assume you know what you are seeing without paying attention to the details. But, no matter the name, it is a stunning caterpillar and a joy to discover just outside our home in the woods.


The larva of the Royal Walnut Moth is a striking object. With its curved horns and numerous spines it presents to the uninitiated a truly repellent aspect.

~W.J. Holland, in The Moth Book, 1968

Hickory Horned Devil

Hickory horned devil caterpillar (click photo to enlarge)

I must agree with Mr. Holland in that I have seen many “uninitiated” people react with horror on their first sighting of a hickory horned devil. But I, and many of my caterpillar-loving friends, think this gargantuan larva is one of the sweetest finds you can make on any summer walk in the woods. And that is exactly how I reacted a few weeks ago as we hiked out to Morgan Creek with our 16 summer campers for some creek dipping. As we neared the creek bottom, I spied some frass (caterpillar poop) in the trail. Anytime I find a cluster of frass on the ground (especially large ones like this), I look up in anticipation. After some searching, I found it, and was thrilled to see it was a hickory horned devil. It was feeding on sourwood, a host species I have never found one on before. I left it until we had finished with the creek sampling and then collected it on the way back to the classroom.

The kids were amazed at its size and further astonished that it still had some growing to do before it was done as a caterpillar. We named it Harvey (why not?) and they excitedly checked on it every day. On Friday, Harvey stopped feeding and hung under a branch, motionless. I decided to take it home for the weekend to watch it and provide fresh food, but the larva did not move until Sunday morning when I looked in and saw this…

hickory horned devil after shedding its skin

Hickory horned devil after shedding its skin

Harvey sat motionless for two entire days prior to this molt. He remained in that position much of that morning and then finally turned around and began to eat his shed skin, something I have seen these larvae do every time I have raised one.

Hickory horned devil starting to eat its shed skin

Eating the shed skin, horns first

Over the next couple of hours, I checked on its progress as the larva slowly consumed the shed skin, starting with the formidable spines.

Hickory horned devil eating its shed skin

Almost done

By the next morning, Harvey had acquired his new set of colors, the bold green with stripes and the orange “horns” that cause people to worry (unnecessarily) about their safety should they encounter this behemoth.


Final instar of a hickory horned devil

Harvey then did what caterpillars do best – he ate and ate and produced a lot of rabbit  scat sized frass. He did this for another week (with a new group of admiring summer campers) and then the final change began. It starts with a blue-ish tint appearing in the green background color. Then he stopped feeding and began crawling about the cage, a sure sign that the search is on for a place to pupate (this species burrows into the soil to form its pupa).

hickory horned devil shrinking for pupation

Harvey shrinking and getting ready for the long sleep

Over the next couple of days Harvey started to shrink. By week’s end, he was about 1/3 his original size, but would still wriggle if touched.

Hickory horned devil approaching pupation

The day before the pupa

The last morning of camp, I looked in the container and the final shed had occurred, his old skin lying next to the fresh pupa.

Hickory horned devil  fresh pupa

Shortly after the last shed, the beginnings of a pupa (it darkens over time)

The pupa took a couple of days to harden and darken. Harvey will now wait until at least next summer (some overwinter as pupa for 2 years I have read) before emerging as a beautiful Royal Walnut Moth. Thanks, Harvey, for allowing two groups of summer campers (and some astonished adults) a glimpse into part of your amazing life.

Royal walnut moth

The final product (a Royal Walnut Moth)…next year








Inside a Rolled Leaf

Everything has beauty, but not everyone sees it.


It has been so busy lately that I tend to forget to “stop and smell the roses”, to take advantage of where I work and live, and to make the time to just look around, ponder, and be amazed. Luckily, I remembered to do just that a couple of weeks ago when I saw some rolled leaves on one of our water garden plants, Powdery Alligator Flag, Thalia dealbata. I am not that familiar with this species, but it seems as though something has taken a liking to the large, canna-like leaves this spring. Horticulture staff commented that this type of defoliation on this species was not common. We were all curious as to who the leaf-rollers might be.

rolled Thalia leaf

Rolled leaf caused by caterpillar (click photos to enlarge)

I peeked into some of the rolled leaves and could see a green caterpillar in some of them. Leaf-rolling is a great way to provide some shelter for yourself and is seen in many types of caterpillars. I googled leaf-rolling on Thalia and quickly discovered that this was probably the work of the larva of a Brazilian skipper, Calpodes ethlius. Larvae are commonly found on leaves of canna, although Thalia is also mentioned as a host.

Brazilian skipper larva inside rolled Thalia leaf

Peeking under the leaf reveals the leaf-roller tucked inside

To create their feeding shelter, the newly hatched larva chews two parallel lines of leaf tissue from the leaf margin toward the center of the leaf. It attaches silk strands to both the outer and inner edges. As the silk dries, it contracts, pulling the leaf into an open-ended tube in which the larva hides.

Brazilian skipper larva in powdery alligator flag (Thalia)

Teasing open the leaf roll reveals the prepupa

That first day, I had teased open a shelter and seen the small caterpillars but did not have my camera. On my next visit, several days later, I found some huge larvae and a prepupa. I must confess I didn’t notice it was already in the prepupa stage until I looked at the images. Close inspection of the photo above reveals the silk strand that forms a girdle attaching the larva to the leaf ,about 1/3 the way down the body from the head. You also can see the large amount of silk along the leaf midrib and how it appears the posterior end of the larva may be attached by silk strands.

Brazilian skipper chrysalis in rolled leaf

On another leaf, a chrysalis

Inspecting another rolled leaf, I found the strange-looking chrysalis of this species. I had seen a photo online and had hoped to be able to see one for myself, and here is was!

Brazilian skipper chrysalis a few days before emergence

An unusual shape

Brazilian skipper chrysalis close up of head region

Small horn-like projection at the anterior of the chrysalis along with a silk girdle

Brazilian skipper chrysalis close up of tail region

The posterior of the chrysalis with the proboscis sheath extending from below

There is a small anterior horn (could this be the antenna inside?) and a long tube coming from the underside that extends beyond the posterior part of the chrysalis. We wondered what that was and I finally found a reference that said it contains the long proboscis of the skipper. I cut this leaf and brought it into my office where I set it up in a vial of water in the window, hoping to witness the emergence of the adult.

Brazilian skipper chrysalis a day before emergence

The day before emergence – an odd-looking pupa

Five days passed, and the pupa took on a new look. You could see more of the developing skipper inside.

Brazilian skipper chrysalis closeup right before emergence

The eye looks huge in the developing pupa

The huge eye of the adult was particularly noticeable. In many species, when you can see more of the adult inside the pupa, that is a signal that it will soon emerge. As luck would have it, I had off-site first aid training the next morning, and when I returned…

Brazilian skipper a few hours after emergence 1g

The freshly emerged Brazilian skipper

I found an empty chrysalis, and, at first, no skipper. Searching the office, I finally saw some movement under some of the debris-pile on my table next to the window. I grabbed a twig and gently picked up the fresh skipper. What a beauty (and that eye is huge)!

Brazilian skipper a few hours after emergence

According to the official record-keepers of The Butterflies of North Carolina, the Brazilian skipper is a somewhat rare species in our state, especially in the Piedmont. Details of the flight period and life history in our state are not well known. It is a migrant from further south (it is more common in Florida), but it does breed in North Carolina. I’ll drop a note to the compilers of the list and let them know we have this rare beauty this summer at NCBG. I’m really glad I peeked inside that leaf roll.


BugFest Residue

If you have a chance to play in nature, if you are sprayed by a beetle, if the color of a butterfly’s wing comes off on your fingers, if you watch a caterpillar spin its cocoon– you come away with a sense of mystery and uncertainty.

~Michael Crichton

BugFest, the NC Museum of Natural Sciences’ premier special event, is over. Somewhere around 29,000 people visited this year, and, as always, we talked to a lot of them about the caterpillars we collected in the days leading up to the event. A lot of effort goes into preparing for the event, by everyone involved. For us caterpillar wranglers, it means finding and caring for a variety of fascinating critters, and then releasing them all back into the wild. Every year we have specimens that never make it to the big day because they either pupate or have been parasitized and die. So, there are many things that our visitors miss seeing. Here is something that only a few us were privileged to witness this year.


Mystery cocoon (click photos to enlarge)

Let’s start with a mystery. I found this cocoon on a leaf in one of the cages with multiple species of larvae we collected right before BugFest. It reminded me of a tussock moth cocoon of some sort since it appears some of the “hairs” from the caterpillar have been incorporated into the cocoon covering. I didn’t have time to do much with it until after the event. I looked at it more closely, and then remembered we had collected a very nice spotted apatelodes (Apatelodes torrefacta) caterpillar who had started to shed its setae the day before BugFest.


Spotted apatelodes caterpillar

I was disappointed at the time, because these large larvae are certainly in the cute category of caterpillars, especially if you manage to get a look at their undersides…

Spotted Apatelodes showing red proleg feet 1

This caterpillar looks like it is wearing red socks

They are one of the only larvae I know that dress like a friend of mine from my museum days (you know who you are) and wear outlandishly bright “socks” (in this case, red, instead of the purple ones my friend still wears). When I realized I had not seen the pupa of this particular specimen, I googled it, and there it was, mystery solved – it is a spotted apatelodes cocoon.

I’ll share a few more of the leftovers from our caterpillar collecting efforts in the next post.

Last Larva?

…one’s first impression might be that this creature has somehow lost its way out of an Amazonian jungle.

~David L. Wagner, describing the Crowned Slug caterpillar in Caterpillars of Eastern North America

When I returned from our California trip, I looked around the yard and saw what lies ahead – lots of yard work. Seems as though autumn had arrived while we were away – leaves changing colors and dropping, branches and twigs littering the ground, and an accumulation of acorns on the back deck. This is apparently a good year for the mast crop (acorns and hickory nuts). So, I began by sweeping off the walkway and deck.

bucket of acorns

Cleaning up the acorns on the deck (click photos to enlarge)

The two large oaks out back drop an impressive number of acorns every few years (usually with a resounding clang on the metal roof and deck). I swept up almost a 5-gallon bucket of nuts that had fallen in a week and a half.

Crowned Slug 1

Crowned Slug caterpillar

As I finished sweeping up, I noticed a splash of color on one of the fallen oak leaves – a caterpillar. And not just any caterpillar, one of my favorites, the Crowned Slug (Isa textula). This is one of the more bizarre-looking of the “stinging” caterpillars.

Crowned Slug close up

Close up of stinging spines

This unusual species is characterized by a series of lobes projecting from the sides of the body, each lobe containing an array of long, stinging spines. Additional stinging spines are found in clusters near the middle of the dorsal surface. The head region is marked by two elongate projections edged in red.

Crowned Slug from below

Crowned Slug feeding on dried oak leaf

I was initially surprised to find one so late in the season, and to see it feeding on an obviously dry fallen leaf. But when I looked it up in Caterpillars of Eastern North America, the author said these caterpillars may be active very late in the season, sometimes dropping down with autumn rains and wind. So, I guess it is not so unusual after all.

Crowned Slug

A beautiful way to finish another great caterpillar season

After spending a few minutes photographing it, I placed this late larva on a fresh oak leaf out back. If this is the last larva of the season, it is a memorable one…slug royalty. I’m already looking forward to next year…


A caterpillar is basically a flexible tube…it is designed purely for eating and growing.

~Michael Chinery, in Butterflies and Day-flying Moths of Britain and Europe

Eat, poop, eat, poop…such is the life of a caterpillar. After BugFest, I kept a few of the specimens for a couple of days before releasing them back into the wild (where they were found) in order to observe and photograph them. The tough part of rearing caterpillars is providing them with enough of the right kind of food. It can get to be a full-time job if you have too many larvae living with you.

Spicebush Swallowtail larva feeding on Spicebush leaf

Spicebush Swallowtail larva feeding on Spicebush leaf (click photo to enlarge)

Some are picky eaters, like the Spicebush Swallowtail larva above (eats Spicebush and Sassasfras in our area), and feed on only one or two species of plant. Others are generalists, and can be found on a wide variety of plants, but some may prefer whichever plant species they were originally eating.

Whatever the diet, they tend to eat relatively little when small (first couple of instars). But, as they grow and molt, they really become eating machines. It is tough to find data on how many leaves one caterpillar can eat but one reference on monarchs estimated a single larva could consume all the leaves on a Common Milkweed plant by the time it was ready to pupate. Certainly, the last instar of a Monarch larva can consume 4 or 5 of the large leaves before forming a chrysalis. That’s a lot of food!

I love watching them munch through leaves. You can even hear larger caterpillars eating. So, in honor of the ending of another caterpillar season, I present a few short clips of caterpillars chomping on their larval lunches…






Disguised Beauty

…the repulsive larva, tissue by tissue, is transformed into the superlative beauty of the adult moth. Beauty will come from beauty in disguise.

~Edwin Way Teale, on caterpillar transformation

Monkey Slug tan color

Monkey Slug caterpillar (click photos to enlarge)

This was a good year for some unusual caterpillars. For some reason, while looking for larvae a couple of weeks ago, we managed to find several of one of the strangest larval forms to be found in these parts, the Monkey Slug caterpillar, Phobetron pithecium. As if Monkey Slug wasn’t weird enough, this well-disguised creature also goes by the moniker of Hag Moth larva. You can read more about these cryptic critters in a previous post from last year’s BugFest outing.

Monkey Slug orange color

Monkey Slug larvae can be various shades of color from tan to rust

These guys can be difficult to spot as they tend to look like a piece of dried leaf edge. They are generalist feeders which means you can’t search just a few types of plants for them. It’s more a matter of developing a search image and just plain luck. This year we found them on an elm, a multi-flora rose, and a hickory.

Before returning the larvae to their former haunts, I kept them for a couple of days to observe their behavior. Turns out they fit the family name, Slug Moth caterpillars (Limacodidae), and are quite sluggish in their feeding and movement. Here is a short clip of one feeding when viewed from below.

It reminds me of an odd-shaped, fuzzy mitten trying to gnaw the edge of a leaf. The larva tends to keep its head tucked much of the time.

Monkey Slug from below

Monkey Slug from below

These are listed as one of the “stinging” caterpillars with various references saying they have urticating spines hidden in the “hairs” of the lateral processes (wavy arms), and perhaps elsewhere on their body. I wonder if those whitish tufts visible along the sides, when viewed from below, are also clusters of stinging spines?

This individual was fairly active on its host twig and I managed to twist the twig around to watch its locomotion skills. Another short video clip clearly shows why this group has the word slug in its family name.

While somewhat slow, and definitely bizarre, these caterpillars are one of my favorites. Now, I just need to find an adult moth at my moth light next year.

Blending In

When we see leaf-eating insects green, and bark-feeders mottled grey, the alpine ptarmigan white in winter, the red-grouse the colour of heather, and the black-grouse that of peaty earth, we must believe that these tints are of service to these birds and insects in preserving them from danger.

~Charles Darwin

Yesterday, while working in the yard, I stumbled across an unusual caterpillar just beneath the surface of my mulch pile. Two things about it jumped out at me – first, it was pretty large compared to most caterpillars so early in the year, and second, its colors were so striking. And then, to add another, when I picked it up, it jumped and thrashed from side to side.

Ilia Underwing larva on twig

Ilia Underwing larva (click photos to enlarge)

I remember seeing a picture of this species in my caterpillar bible (Caterpillars of Eastern North America, by David L. Wagner) but this was the first one I have encountered. After identifying it as an Ilia Underwing, Catocala ilia, I discovered it is actually one of the most common of the underwing moth species in the East. How have I missed seeing one all these years? Then I read that there is only one generation per year and mature caterpillars are most often seen in early spring. To be honest, over the years I admit to doing more of my caterpillar searches later in the season, when some of our more showy species reach their full size. Look what I have been missing! Sources say that the eggs are laid in the fall and hatch in early spring. The larvae feed primarily on oak leaves. Perhaps my find was burying down into the mulch getting ready to pupate.

Ilia Underwing larva showing rosy underside

Ilia Underwing larva showing a glimpse of the rosy underside

The dorsal surface can be gray or brown, or, as in this case, a mottled color that is a great mimic of a lichen-covered twig. One thing they have in common is a noticeable rosy color to their ventral surface (this guy did not like to be handled so here is just a glimpse of its rosy underside).

Ilia Underwing larva on lichen 2

Ilia Underwing larva blending with a lichen-covered branch

I brought the larva inside with a couple oi twigs I found laying nearby and photographed it. When I nudged it onto a twig, it would thrash, and then crawl a short distance and assume the position. When on a bare twig, it clings tightly but is visible (perhaps the gray or brownish larva blend in better on bare twigs). But when it crawled onto the lichen-covered branch, I could see how this caterpillar can literally disappear before your eyes (or perhaps those of a hungry bird).

Ilia Underwing larva on lichen close up

The color patterns and textures of this larva are a great lichen mimic

It is always a treat to discover something new and learn how it lives its life just outside my window…all I need to do is get outside and look to once again be in awe.

So Many Green Things, So Little Time…

black swallowtail caterpillar after molt

Black Swallowtail caterpillar after molt (click to enlarge photos)

There has been a spate of caterpillar sightings the past few days, especially of the big green kind. I know this is just to get me overly hopeful that some of them may actually still be around for use at the caterpillar tent this coming Saturday at the NC Museum of Natural Sciences big special event, BugFest ( see for details). Indeed, the timing of BugFest this year has me worried that many of the cooler cats that have been out and about will decide it is time to pupate a day or two before the event, leaving us with a precious few to entertain and educate the thousands of visitors expected to attend. It has been a great year for Black Swallowtals in the garden, but suddenly, the caterpillars have all but disappeared, as has their food supply of parsley and fennel. I saw one female laying eggs late last week, so I am hopeful a few of them make it, but most are busy feeding and molting their way to pupation in a hurry as the cooler weather sets in.

Luna caterpilar on Persimmon

Luna Moth caterpillar on Persimmon

I was checking a Persimmon tree late last week and was surprised to find this guy, one of my favorite caterpillars, feeding on it. This is the larva of one of the most beautiful moths in our area, the Luna Moth. I usually find them on Sweet Gum so I initially thought this was a Polyphemus Moth caterpillar as my experience has been that species favors a wide variety of tree leaves. But a closer look revealed the tell-tale yellow stripe along the length of the abdomen and the stripes at the trailing edge of each abdominal segment that separates the Luna from the Polyphemus (whose oblique stripes run through the spiracles along the sides).

Tobacco Hornworn on tomato

Tobacco Hornworn on tomato

The final big-green-eating-machine found last week was a Tobacco Hornworm on one of my few remaining tomato plants. This has not been a good year for tomatoes in my garden as the excessive early rains may have encouraged the blight, so there have been relatively few of these common garden caterpillars around. When disturbed, this one pulled into the characteristic posture that gives this family its name—they elevate the front part of their body and assume a posture reminiscent of the Egyptian Sphinx. Unfortunately for me, this one is large enough that it most certainly won’t last until BugFest. But, I will be out and about looking for more (hopefully successfully) the next few days so I hope you will tolerate a few more posts on caterpillars. They are one of my favorite subjects to photograph and I have found them to be one of the best ways to help get people of all ages excited about nature. If you are in Raleigh on Saturday, September 21, be sure to stop by  the caterpillar tent outside the main museum and let us share the excitement with you.

And a late note…I had this prepared to post tonight but went out today looking for caterpillars and had quite a day – more in a future post later this week.

Dressed for Success

And what’s a butterfly? At best, He’s but a caterpillar, drest.      John Grey

And there is one species of caterpillar that dresses better than any other – the Camouflaged Looper, Synchlora aerata. This is the unusual larva of the Wavy-lined Emerald Moth (okay, the quote isn’t quite right in this case…).

Camouflage Looper

Can you see the caterpillar?

Every time I am out in the garden I always take a few moments to just look around for interesting critters. As I watched a few pollinators on the Blazing Star (Liatris sp.) yesterday, I noticed something move. But there was nothing there…then it moved again, and I knew what it was – a Camouflaged Looper. This caterpillar has the unusual habit of disguising itself by cutting plant parts from the flowers on which it is feeding and sticking them onto its dorsal surface. The larvae feed on a wide variety of plants although I have most often found them on Blazing Star, Black-eyed Susan, and a few other yellow composite flowers.

Camouflage Looper 3

Camouflage Looper and its “costume”

In a 1979 article in The Journal of the Lepidopterists’ Society, Dr. Miklos Treiber, of the University of North Carolina, wrote about the camouflage abilities of these inchworms. The larvae cut off flower parts, seeds, and even entire flowers, and attach them to needle-like projections on their upper body surface. In a series of experiments he removed their floral covering and they immediately  began to replace the camouflage.

Camouflage Looper on yellow flower 1

Camouflaged Looper on yellow composite

Furthermore, when moved from one flower type to another (purple to yellow in his case) the larvae began to replace their old camouflage with flower fragments from the new plant.

Camouflage Looper 4

Camouflaged Looper on Blazing Star

He also noted that the fragments are passed through the mouth of the larva before being attached and that a mucilaginous substance (aka “caterpillar spit”) was secreted by the larva onto the fragments. He speculated that this substance seems to play a role in maintaining the freshness in these fragments. The caterpillars also maintain the effectiveness of the covering by replacing withered floral parts with fresh ones.

Camouflage Looper 5

Camouflaged Looper looks like plant debris when not on matching flower

Dr. Treibe hypothesized that this looper’s ability to change disguises allows it to have a much more varied diet than some other caterpillars because it isn’t restricted to eating only those flowers or plant parts that it resembles in appearance. And I noticed that even when it is moving between flowers and is on a stem, leaf or other background, the caterpillar simply looks like some plant debris rather than a potentially tasty meal for any passing bird.