It’s finally fall here in New England, and the insects are on their way out – either dying, or bundling up for the winter. However there are always a few that cling to life through the first few cold nights, unwilling to admit that summer is over (I know that feeling quite well).
Here are a few caterpillars I found while walking in a nearby park at dusk.
First is Schizura unicornis, the Unicorn Prominent, of the family Notodontidae. In this photo you can see the “horn” from which the name is derived. It looks as if the caterpillar is molting, with the old head capsule just barely clinging to the head.
This species overwinters as a larva, fashioning a protective cocoon in leaf litter. They wait until spring to actually pupate, which is unusual amongst caterpillars (typically pupation occurs in the fall, and the winter is spent as a pupa). I imagine these caterpillars will be above ground feeding until their host plants succumb to the cold.
These caterpillars appear to be Hyphantria cunea, the Fall Webworm, of the family Erebidae. There were several fuzzy clumps of them on various plants, surrounded by loose webbing. These guys will continue to live gregariously in their messy webbed homes until they are ready to pupate in preparation for the winter. I’ll keep on the lookout for others, there are still plenty of hardy, determined caterpillars out there.
If you hear the phrase “monkey slug”, your first thought is probably not of a caterpillar. But that is indeed the common name for Phobetron pithecium, a caterpillar/moth in the family Limacodidae.
Limacodidae are collectively known as the slug caterpillars due to their reduced legs and slimy looking underbelly. They even crawl by means of a liquified silk trail that they glide effortlessly across. So that is where the “slug” part of the name comes from. But “monkey”? No one is quite sure. The adults are called hag moths, which doesn’t sound very flattering, though they are adorable little moths.
I have never seen one of these caterpillars in the wild, however a friend of mine (Sam Jaffe of The Caterpillar Lab) was kind enough to part with a few of his fuzzy little charges. I have no use for them in my research, but they have been fun pets.
A few more facts:
They can cause allergic reactions in some people (I have not tested myself yet, but just look at those hairs and spines!). However they have glided across my hands with no reaction, so it would probably require rubbing the hairs into your skin.
They do have a head, but it is usually hidden.
They feed on a variety of trees and shrubs, mine are feeding on oak.
The “arms” can come off, the hairs are in fact embedded in a scaffold of some sort of slime that covers the body. This is a feature common to many limacodids.
Here are some photos I took of these guys today.
Surprise surprise, right?
The caterpillar lab has been humming along. My advisor was away for a month to explore the southwest and collect a few hundred caterpillars for his next field guide… meanwhile a few lab members and I kept things running around here. Collaborators began sending me more and more material (I currently have about two hundred caterpillars in my care). I even started some real data-gathering experiments!
My advisor returned this past weekend and the lab has been in a frenzy. Jars of caterpillars and bags of plants everywhere. Boiling specimens and trying to not forget about them lest they fry on the hot plate. Urgent requests to run outside and grab a branch of the oak tree out behind the building (or the milkweed down the street, or the birch by the pond, or the alder at the stop sign…).
Here is the lab table right now, actually looking remarkably clean and organized. There are several boxes of caterpillar vials on nearby shelves:
And my caterpillar station:
It is amazing how easy it is to get caught up in the daily grind of feeding caterpillars, cleaning out poop, setting up freshly hatched first instar caterpillars, taking photos, collecting plants, etc. Sometimes I nearly forget exactly what I am supposed to be doing with these guys – experiments! Once I get some pictures organized I’ll let you know what I’m up to… it’s about defensive behaviors. So far so good, and hopefully I’ll have enough data to present something interesting at the Entomological Society of America conference in November. Fingers crossed.
To keep costs down, Ben and I decided to camp for the entirety of our Texas trip (aside from two nights at a colleague’s house). This made our trip feel even more adventurous. We’re used to showing up to a research station with dorms, a kitchen, and a laboratory with supplies. This trip was quite different! We brought my tent, and bought some cheap sleeping pads and sleeping bags at Walmart when we arrived. We also bought some batteries to run our lights, and parts to build a light trap.
We arrived in Dallas, loaded up the car with supplies and food, and drove out to Abilene State Park. I truly did not believe we would fit all of our supplies into a compact rental car, but we did.
The area seemed scrubby, a little dry, and an odd mix of forest, scrub, and almost-desert habitat. The air was hot and humid. There were only a few other people in the campground, as this is not an ideal time to be camping in Texas. As soon as the tent was set up, we set off to explore.
We saw a few caterpillars just by walking around – like this little notodontid.
Our daytime caterpillar search wasn’t terribly fruitful though, so we held out hope for the night. We weren’t too impressed with what the light brought in (our campsite had electricity!), but we did have fun (and strained our necks) looking for caterpillars. We were spooked by a few raccoons, but otherwise didn’t run into any trouble.
Our first big find turned out to be an Acronicta caterpillar! I spotted it sitting on a branch just above my head. I instantly recognized its fuzzy gray body as belonging to Acronicta lobeliae.
But I wasn’t prepared for what happened next. After taking this photo, I reached toward the caterpillar to pick it up. It instinctively dropped to the ground, where it landed directly into an antlion pit! It thrashed around as the antlion tried dragging it under the sand. I quickly scooped up the caterpillar but it appeared paralyzed or dead – frozen into a half curled position.
I kept the poor guy anyway, and within about an hour it was back to normal. Whew!
Here are some other pretty caterpillars we came across:
We weren’t blown away by our first night, but I was quite happy to have an Acronicta caterpillar in hand. We stayed one night, and the next day continued our journey west, to Fort Davis.
We recently received a new friend from Texas – nicknamed “Joe Acronicta” by the collaborator who sent him to us.
This is one of my favorite species – Acronicta atristrigatus, also known as the “Paddlemaster”. I bet you can guess why.
What we’re all wondering, though, is what those paddles are for. They appear on several Acronicta species, but in different arrangements. Some only have them in place of the dorsal setae, while others are nearly covered in paddles. I have a feeling they are used to thwart parasitoids which may try to land on the caterpillar to lay their eggs. Many species of flies and wasps see caterpillars as big tasty meals for their offspring.
I imagine all those hairs would make it difficult for a parasitoid to land. And if it does, the caterpillar will surely notice.
These guys also have some interesting defensive behaviors.
Don’t worry, I did not hurt the caterpillar! Like most Acronicta species, it starts with a bite (or attempted bite). But instead of simply returning to its perch, the caterpillar begins to sway side to side. We are all curious as to whether this serves to deter birds, or parasitoids, or perhaps the caterpillar is trying to sway gently like a tree branch?
What do you think?
I thought it would just be a cute addition to my collection of insect books, but it has really wonderful illustrations featuring a wide variety of behaviors and natural history. The author and illustrator really knew their caterpillars. The caterpillars are all based on real species found in North America. The illustrations feature eggs, first instars, morphological changes, defensive behaviors, molted skins, feeding behaviors – even frass flinging!
That caterpillar in the middle is clinging to the stem face down, and has twisted its rear end over its back in order to shoot its poop. This book was definitely written by an observant nature lover.
I’m calling this my new favorite book, and highly recommend it for anyone who likes caterpillars. I think the target age is about 5 or 6 years old… but… no one will judge you.
Gladys Conklin wrote a variety of children’s books on insects and other animals. Some titles include “I Watch Flies”, “When Insects are Babies”, and “I Caught a Lizard”. I want to buy them all!
My caterpillar colleage Sam Jaffe has created a kickstarter project – an ambitious plan to create a series of programs and events using live caterpillars for science education outreach. If he’s funded, he’ll do it all this summer!
Sam is an amazing photographer and great caterpillar wrangler. Please consider donating to his cause, or at least check out his work – his photos make caterpillars look nearly as cuddly as the plushies I sew!
We are so excited for the next pool throwdown against our rival entomology lab (well, it’s a friendly rivalry) after this month’s Connecticut Entomological Society meeting. We’ve got our own lab shirts, now.
I designed the shirts after a brainstorming session with the lab. We decided on a caterpillar, playing pool, wearing a cowboy hat. We were thinking of including a mustache but thought that would be a bit too much. The caterpillar species is Acronicta increta (indeed I couldn’t help but include one of my own study species).
While at the Smithsonian National Museum of Natural History, (see previous posts here and here) I did manage to tear myself away from the collections long enough to browse some of the public exhibits. I did not go into the butterfly house (didn’t have my wallet with me, you have to pay to enter), but I did see some caterpillars!
There was a whole section of the museum devoted to insects and invertebrates, with many live organisms on display. There were a lot of the usual suspects (mantids, tarantulas, roaches), but they also had some hornworms (Manduca sexta). There was a display with a multitude of pupae, a few caterpillars, and one freshly emerged adult. It was being nibbled by a persistent, and apparently violent, caterpillar. I do not know why.
There was also a display where you could see some pupae of various species hanging – waiting for their chance to emerge and become part of the butterfly house. There were not just butterflies, though. I could see many moth cocoons, the fuzzier looking ones at the bottom.
And I really liked the displays! The blatant emphasis on evolution in almost every single display and description is refreshing (the hall of human origins is wonderful). Whenever I start to despair and worry that there is not hope for humanity to accept science, I should go visit a natural history museum. They don’t hold back.
Now I just need to start planning my next trip back. Hopefully within the next few months! (and maybe I’ll schedule some time to be a tourist)
I have determined that a friend of mine, who works in another lab, has access to materials I could use for inflating caterpillars. I can’t wait until the collecting season starts and I can start on my own specimens.
While some inflated caterpillars are curated within the main collection, and some of them are grouped by family in the larval cabinets, there are many “miscellaneous” drawers with arrangements like this.
All sorts of caterpillars! The nice green color of the swallowtail caterpillars (bottom right-ish) was not preserved though. This seems to be one limitation of caterpillar inflation – patterns remain, but colors become lost or distorted. Most inflated caterpillars are some shade of tan/brown. This could be due to the heating process or simply by fading over time due to light exposure.
One thing I did not expect to see – everted osmeterium! Swallowtail caterpillars (Papilio) have an eversible gland called the osmeterium which is normally held inside the body. When threatened, the caterpillar sticks out the two forks and tries to touch the attacker – wiping them with smelly defensive chemicals. Just the smell could be enough to deter a would-be predator, but I’m sure the taste is pretty bad too.
Many of the geometrid caterpillars were preserved in their usual hunched position. I wonder if this was induced somehow during the heating process, or if they simply inflated into the most natural position?
I couldn’t help but include a photo of the megalopygids (fuzzy guys on the right). Preserving them must have been a delicate task, hopefully carried out with gloves – they can give quite a vicious sting! They look more like little mice than insects, and each hair can leave a welt on your skin. I was tempted to test whether old preserved specimens would still sting, but decided not to try.
Have any of you ever inflated a caterpillar specimen before? If yes, do you have any advice?