Category Archives: Acronictinae
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.
There are several ways to preserve caterpillars for study. You can boil them and drop them into a jar of alcohol, you can freeze dry them, or you can inflate them.
The photos in this post are all of inflated caterpillars, in the genus Acronicta, found at the Cornell University Insect Collection (CUIC).
Inflating (or “blowing”) caterpillars is a traditional technique that is no longer taught or commonly used, however it can produce fabulous results. The caterpillar remains dry and can be kept in a drawer along with adults, which makes them easier to study than specimens in alcohol. Their external features are usually well maintained – specimens from the early 1900s don’t look much different from modern specimens.
However they are lacking their internal organs, and the last couple of segments are destroyed in the preparation process. The technique is also quite labor intensive and requires unusual equipment. So how does it work?
I have talked to a few entomologists who have inflated caterpillars, but not since their undergraduate or graduate school days. I have found a few resources which describe the process. Here is a description from the University of Minnesota Agricultural Experiment Station:
Basically you cut a slit into the posterior end of the caterpillar, and using a pencil, roll out the guts (starting at the head end). You must be careful to not destroy the hairs and other features of the exterior. Then you insert a glass tube and inflate the caterpillar, and keep the caterpillar inflated as you heat it in a small make-shift oven. One colleague described using a coffee can over a bunsen burner for this purpose.
Once the caterpillar is dry, the glass tube is removed and the caterpillar can be prepared for pinning. Either a wire or stick can be inserted, or the caterpillar can be glued onto the wire or stick by its prolegs underneath the body.
A box of Acronicta americana adults, caterpillars, and pupae
Late (above) and early (below) instars of Acronicta morula
Another benefit of inflating caterpillars is that the body shapes are extended and not distorted by being kept in a liquid. The important bumps and hair positions are kept as their were in life. However the body may be a bit overextended depending on how well it was squished and inflated.
One reason I particularly enjoy the inflated caterpillars is that they are easy to transport and trade – so there are many European species in collections here in the USA. Caterpillars are not often kept in collections to begin with, so to have these specimens available to me for study is quite exciting.
As you can probably guess, I’m going to set up my very own caterpillar inflating oven as soon as I can! And I’ll have another post soon on even more inflated caterpillars I have found at other collections.
University of Minnesota, 1908. 16th Annual Report of the Agricultural Experiment Station. Bulletin #105. How to Collect and Preserve Insects. Pages 119-146.
My schedule this semester actually allows me to spend long chunks of time looking at caterpillars. Finally! It’s really difficult for me to work on my morphological datasets in small bits of time (like one hour between classes/seminars). But three to five hours at a time with no interruption… glorious.
Aaaand we’re off – to see if some of my caterpillars are chemically protected.
This is my arm right now:
I’m about to go rub some caterpillars on another lab member.
(It’s ok, we’ve filled out the human testing protocol paperwork.)
So far I’m intrigued that these three species have all given me the same type of reaction in terms of timing, appearance, and sensation (it burns, and then itches). Other people in the lab have reacted to them as well, but I want to document this in a systematic fashion. It could be an important phylogenetic character. So far we’re pretty sure two of them are in the same clade, and the other we are going to add to our molecular dataset soon.
Here I am with some caterpillars (Acronicta impleta)… that I am about to start testing for chemical defenses by rubbing them on my arm. From a few reactions I’ve had, it seems there is one clade within the genus Acronicta which are chemically protected. I am still sporting a rash from a caterpillar I rubbed on my arm a week ago. For science!