Category Archives: Acronictinae
On Saturday night I joined a bunch of entomologists for the 5th Annual Moth Ball in Massachusetts. Lights, sheets, cameras, beer, hotdogs, snacks, and tents for staying overnight. What could be better?
I was also on a mission. One species my advisor has been telling me I need to get ahold of is Acronicta hastulifera. As an adult it is nearly indistinguishable from Acronicta dactylina, though their caterpillars are quite different. The best way to make an ID, then, would be to catch a caterpillar and rear it to adulthood, or to get eggs from a female and raise the caterpillars. This is not always easy to do.
I found a few Acronicta females at the moth ball, nothing terribly exciting. Though it wasn’t long before a friend of mine approached with the grand prize in his hands (from a nearby sheet): Acronicta hastulifera. A big fat female! Success! The rest of the night paled in comparison to that moment.
When I awoke in my tent the next morning (after only a few hours of sleep), the first thing I did was check her container for eggs. About a dozen big green eggs dotted the sides of the vial. Woohoo! Last night I set her up in a larger container, and she really let loose. I estimate 200+ eggs.
At first I was a little worried that all of the eggs were remaining green. With other species that is sometimes a sign they are infertile. But once they gain some spots and other coloration, you know the larva is developing inside. Like this:
I hadn’t seen a spot pattern quite like that before (the things on top are the mother’s scales).
Now I must be patient and wait for them to hatch. Most Acronicta eggs take five or six days. I’ll be ready with some Alder (their favorite food), and my camera to get pics of the little ones.
Oh right, Texas! It already feels like so long ago, we’ve been so busy here in the lab.
Our second stop in Texas was Davis Mountains State Park, in Fort Davis. It was another long drive across flat, desert-like land. We saw several hundred (thousand?) wind mills, which created a very eerie landscape. Fort Davis provided an emotional refuge of mountains and trees. We arrived late afternoon, and promptly went for a hike to stretch our legs.
Everyone we had talked to said that west Texas was experiencing a several-year-long drought. When we arrived at the park, it became quite clear they were telling the truth. Trees were clinging to old, tough leaves. Grasses were brown and crunchy underfoot. Wildlife seemed scarce. Aside from a couple whiptail lizards, a ground snake, and some unruly javelinas, the landscape seemed eerily deserted.
By the time we set up camp and settled in it was getting dark, so we set up a blacklight. Not much came in other than micro-moths and midges. Disappointed, we hoped the next day would be more fruitful.
In the morning we got up early for some caterpillar hunting. Well, I went for a run and a workout first, but then we armed ourselves with beating sheets and sticks and began wandering around the campground. There were only a few other people in the park, so the park staff didn’t mind.
Abilene sure was lush in comparison! But we did not give up hope, and searched as many branches as we could reach. Each tap of a tree branch released plumes of dust, pollen, and dead leaves. Surprisingly, we found a bunch of geometrid caterpillars. I wonder why they were the most abundant?
After an hour of not-very-productive searching, Ben shouted “Brigette, I have a present for you!”. Sure enough it was a little Acronicta caterpillar on an Emory oak tree! Despite our renewed enthusiasm and re-doubled efforts, we did not find any more Acronicta in the park. This little caterpillar grew up to be quite interesting – it’s the one featured in this post.
After a quick lunch (which became our classic: gluten free wrap with sliced turkey and a dill pickle) we drove a few miles down the road to the Chihuahuan Desert Nature Center. A place so wonderful it deserves its own post, coming soon!
There are caterpillars called “slug caterpillars” due to their, well, slug-like appearance. They are the Limacodidae, and they are some of the most beautiful and bizarre caterpillars out there.
Not to be outdone, there are a few species in the genus I’m studying, Acronicta, which resemble the infamous slug caterpillars. Blobby green things that hide their heads while at rest.
These caterpillars were raised from eggs laid by a few females I captured in Boerne, Texas. I am uncertain whether they are Acronicta vinnula (common throughout the eastern US) or Acronicta lepetita (native to southern Texas, and so closely resembles A. vinnula that I am unsure how to tell them apart). As far as I can tell, the caterpillars are identical to the A. vinnula I have raised in the past.
It appears that no-one has raised A. lepetita before. Someone please correct me if I am wrong.
The most information I can find is that “the larvae feed on various plants”. Thanks Wikipedia, that’s quite helpful.
What might be more helpful is a look at the adult. Here is one of the mothers.
My caterpillar season is starting to gain momentum. Caterpillars are hatching, eating, growing, pooping. Getting eggs in the mail from collaborators. Running around campus to collect plants. And some of the caterpillars from my Texas trip are approaching pupation.
I was somewhat in denial of this fact until I saw the size of this guy.
That is a FAT caterpillar! I’d never seen an Acronicta caterpillar look quite so much like it’s going to pop. It also wasn’t in a terribly good mood.
Today I found out why. I checked on Mr. Angry Sausage Caterpillar and it looked a bit… different.
The bright reddish orange coloration and jet-black head were an impressive change. I have only seen this sort of change in one other species, Acronicta lobeliae, which also gains a black head and darker coloration before digging a pupal chamber.
I realized this caterpillar had stopped feeding and was ready to pupate. Poor thing was waiting for the right substrate!
I put a piece of soft, spongy wood into the container, since most Acronicta pupate in wood. It found the wood within minutes, and within an hour had chewed a tunnel into the wood. It’s currently sealed up, where it will remain for a couple months until it is ready to emerge as an adult.
I’m still not entirely sure which species this is. It was collected in Fort Davis, Texas. My guesses are either A. afflicta or A. brumosa. What do you think?
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.
Well, we’re off! Ben and I are going to spend 10 days traveling across Texas. We’re armed with several permits (for Big Bend National Park, Texas State Parks, and one National Forest), several suitcases full of vials and lights and other collecting equipment, camping gear, and enough homemade beef jerky to sustain us for several days if we get lost in the wilderness.
Our main target is the species Acronicta valliscola, a species only known from Big Bend. I want to snag it for DNA and hopefully raise the caterpillars, since they have never been seen before! It’s the right time of year and right weather, so hopefully we stand a good chance.
When I return, the beginning of intensive research (and blogging) season will begin. Lots of pictures, lots of caterpillars, lots of discoveries.
While I’m gone the lab will be tended by a few faithful labmates, and my bunnies will be tended by my wonderful boyfriend. So now all I have left to do is… get on a plane before I think of another thing to cram into one of my bursting suitcases.
Wish us luck!
Joe Acronicta had had enough of us poking and prodding him, and decided to pupate.
I know that most Acronicta species pupate by tunneling into soft, dead wood. But usually this is a shallow groove, covered by bits of wood and silk. Sometimes they burrow in deeper, but you can see the hole behind them.
Joe decided to be a bit like some other Acronictines (species in different genera, but still closely related to Acronicta). Genera like Comachara, Polygrammate, and Harrisimemna all dig deep tunnels into wood. Then they crawl out and back into the tunnel rear-end first, sealing up the entrance with silk and bits of wood.
That’s exactly what Joe did.
The cleverly disguised entrance.
I’m not sure how long it will be before he emerges, maybe a few weeks or months? When caterpillars pupate early in the season, it usually (but not always) means they will emerge in time to start another brood before cold weather arrives. If they pupate late in the season, they will usually (but not always) overwinter as a pupa.
While we are pretty sure that we have these caterpillars matched up with the correct adult, we are excited to have an adult emerge so we are 100% sure. I’ll post pictures when Joe makes his appearance as a moth!
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?
It’s springtime, and that means the moths in the lab are emerging from their cocoons. Since it is warmer here in the lab, they tend to emerge a few weeks earlier than they would in the wild. This means we get a head-start on pinning and labeling the moths before the field season gets underway.
One wall of our “rearing room”
It is bittersweet, sometimes, when I meet an adult moth I’ve raised from an egg. Knowing that it will be added to my collection as a specimen. Advancing science, but putting an end to a small, fuzzy life. It doesn’t help that I get quite attached to my caterpillars.
But in many ways I embrace this aspect of my work, as the act of pinning and spreading a moth involves considerable skill, practice, and artistry. I am also a firm believer in the importance of scientific specimen collections. Monday mornings are currently my favorite part of the week because that is when I work in UConn’s biological collections, helping to curate the moths. Each specimen has a history and tells a story.
A freshly emerged adult moth
Some moths on the spreading board
With the emergence of the moths comes the emergence of field gear and enthusiasm. The caterpillar lab can be a dull place during the winter. But this spring/summer promises to be full of adventure, misadventure, and insects. We are starting to receive caterpillars in the mail from collaborators in warmer climates. Moths are fluttering around porch lights at night. Collecting trips are being planned all around the country. I will be breaking out my own collecting lights within the next couple weeks.
For the time being, though, my main duty is pinning my adult moths as they emerge. If you would like to learn more about this task – my friend and I are currently creating an instructional screencast on how to pin a moth – I will post it as soon as it is finished.
One of the great things about being an entomology graduate student is that going behind the scenes at natural history museums is not only a perk – it is virtually required. Visiting a museum collection means new professional contacts, new collaborations and inspiration, examining specimens, and sometimes borrowing specimens to study at home.
Last week, during “spring break” (grad students might get breaks from classes, but never a real break from work) some members of our lab took a trip to the Smithsonian National Museum of Natural History. We drove from CT to DC, stayed overnight at a cheap hotel, and spent the next two days frolicking amongst the insect cabinets. Well, maybe I was the only one frolicking.
Plenty of room to frolic. Carefully.
I actually only spent about an hour, on the second day, exploring the public exhibitions. It was much more fun being behind the scenes, especially with the vast amount of specimens available to explore.
The Smithsonian NMNH holds over 35 million insect specimens in drawers, vials of alcohol, and slides – making it one of the largest insect collections in the world. You can read about the History of the United States Entomology Collections here.
I went to the museum with one major purpose – to see which caterpillars in the genus Acronicta they have preserved in alcohol, and if there are any species I have not yet examined and could borrow for further morphological study. Caterpillars are not often kept in collections (at least not in the same numbers as the more popular adult butterflies and moths) but luckily, the NMNH had what I was looking for.
There were 24 jars of ethanol holding Acronicta caterpillars, each jar containing up to a few dozen small vials with preserved specimens. I looked at every single vial, feeling the familiarity of old friends and the excitement of species I had not yet seen. Some specimens were collected by the authors of a seminal work on Acronicta published in 1898, Smith and Dyar. How cool is it to examine specimens collected by your heroes? I was amazed by the dates on some specimen labels – the oldest I found was collected in 1886.
This caterpillar is 127 years old.
With a spot to sit and look at specimens, the first day absolutely flew by. The entire evening of dinner and sight-seeing in DC felt like wasted time – I wished I could have stayed at the collection. Maybe if I had curled up to sleep under a desk, no one would have noticed?
Science is happening here.
The caterpillars were not just in jars, though. There were also a few drawers of inflated Acronicta larvae from around the world. I took lots of photos, but the memory card from my good camera is currently misbehaving. Hopefully I can recover the photos, though I could always retake the photos on another visit.
Some of the inflated Acronicta caterpillars.
I also met some wonderful people at the museum, and caught up with colleagues I have not seen for months or years. We had some great conversations about field collecting and project ideas. I learned a lot about collecting cave insects while walking through mountains of bat guano – did you know that rabies can be spread through the air? Sometimes entomology can be quite hazardous.
At one point I noticed a toy caterpillar on a shelf in the work room, and gushed over its accuracy and adorable-ness. Later in the day when I returned to my work station, I noticed it sitting on my laptop. My lab members told me I was given a new friend!
Cerura vinula, the puss-moth caterpillar, family Notodontidae. It now happily lives in my office.
The second day was as wonderful and short-lived as the first. I took many more photos of inflated caterpillars, which I will detail in another post. I felt so honored to be allowed to visit and explore such a historic institution, and hopefully will have many more visits over the course of my career.