Monthly Archives: March 2012
First night blacklighting
With the burst of warm weather we had last week I decided to set up my sheet and blacklight outside my apartment. It snowed this morning so the weather has changed a little bit, but for a few nights I was getting a lot of moths! It made me realize just how much work I have left to do before I’m ready to really tackle collecting moths and caterpillars for my research this summer. Looks like the field season will be starting early for a lot of entomologists.
So far it’s a pretty big moth turnout for the end of March in Connecticut.
Technical difficulties, of course
My laptop decided that last week was a great time to get a virus. I’ve been dealing with the aftermath of that for a while (looking to buy a new laptop), and for now I’m stuck on a little hand-me-down netbook. It’s a bit slow for using WordPress, but I’ll try to add a few things.
I have all my files backed up, including pictures from my trip to Canada. I’m keeping that harddrive safe in my office so I’ll get those pics and write about the creatures we found soon.
I’m driving up north to see some friends of mine for spring break and wander around McGill, reminiscing about college days. In between shopping for shoes and eating poutine we will be exploring the arboretum, so I’ll surely have some insect stories to share when I return (my friends are entomologists, what do you expect?).
Is it spring yet?
It was over 60 degrees (F) today. With such a mild winter and only a dusting of snow, can we say it is spring yet? It certainly feels like it with the sunshine and birds chirping.
I woke up with a fever this morning, so I stayed home from school. I hate doing that, I missed my SEM session, but I was a total wreck until the afternoon. Finally able to stand up without feeling dizzy, I went for a walk in the park to get some fresh air into my lungs (in between hacking up phlegm and blowing my nose). At the park there are some little ephemeral ponds, which of course I investigated for insect life.
They were teeming with caddisfly larvae, all with really neat twig houses. I’m not sure what this one was doing at the surface, it looked like a strange yoga routine.
Here is a handful, hidden away in their houses.
Caddisflies are holometabolous insects in the order Trichoptera, most closely related to Lepidoptera. The adults have scaly wings and resemble moths while at rest. The larvae are aquatic and fall into three groups: free living, net-makers, and case-makers. They all use silk to some degree. The case-makers have a variety of species-specific techniques such as using twigs, pebbles, or even arranging pebbles into a snail shell shape. You can imagine that carrying around a house that serves as protection and camouflage is a pretty good strategy, though I’ve noticed it makes them rather clumsy. It was fun watching these insects crawling along the leafy bottom of the pond.
While at the park I also noticed how much trash was strewn about the otherwise beautiful forest edge. I walked home, grabbed a garbage bag, walked back, and picked up all the trash I could find. It didn’t take very long to fill the bag til it was bursting. The most common items were beer cans and slim jim wrappers… the worst thing was a dirty diaper stuffed into a soda cup. Gross!!! I hate people who litter. Unless your life is being threatened, causing you to drop your cigarette or beer can in a fight-or-flight response, there is NO EXCUSE for littering. Ever. The next time I pick up a used diaper or a beer can full of cigarette butts in the park I’m not sure where I will direct my rage, but it will have to go somewhere, and it won’t be pretty.
Caterpillar Mysteries: Systematics, Evolutionary rates, and Mimicry in Acronictinae (Noctuidae)
That was the title of my talk at the EEB grad symposium on Saturday. It sounds pretty impressive, now that I take a step back and think about it. I got a lot of great feedback before my talk to polish it up, and a lot of positive reviews once it was over. I felt like I forgot half the things I wanted to say, which meant I had perfect timing. If you know me, you know that once I get going on a subject I can talk your ear off, so sticking to a 15 minute time limit and leaving a minute for questions was quite an accomplishment.
Anyway, I thought I’d give some teasers as to what my talk entailed. I might delve into a few more as longer posts as I develop more of my ideas and start getting desperate for advice. My biggest problem is having too much material to work with.
First of all, meet some of my caterpillars. These are all in the genus Acronicta, which is in the subfamily Acronictinae in the family Noctuidae. I bet at first glance (and even at a second or third) you would have no reason to believe they are closely related at all! My advisor has called them the “warblers of the caterpillar world”. There are 50+ species in North America, with the highest diversity in the North East. There are about 150 species worldwide. Some closely related genera in the subfamily which may enter into my research are Agriopodes, Cerma, Comachara, Harrisimemna, Polygrammate, and Simyra.
Evolutionary rates – The caterpillars show a huge phenotypic diversity. They extend in all directions in morphological space – different colors, hair types, hair patterns, coloration patterns, camouflage, aposematism, mimicry of other caterpillar species, and even wide variation in behavior. Some rest in a hunch back shape, some sit in a “J” shape, some are conspicuous and some try to hide. However the adults are all dull, gray, unexciting moths. They are growing on me, but drawer after drawer they get a little monotonous. Many species are difficult to distinguish (even to experts), though their caterpillars are distinct. Why is there this apparent de-coupling of evolutionary rates, where the adults don’t deviate much and the caterpillars race into different phenotypes?
I want to address this with a molecular tree (we already created one tree with 25 species to start) and character matrices for the eggs, larvae, and adults. Before we try more molecular techniques I need to collect more specimens, I want to capture as much of the worldwide variation as possible. This will involve some loans and assistance from colleagues around the world, and hopefully some trips.
Taxonomic questions – I don’t want to give anything away by showing our first tree, but so far it has helped address a few small questions we’ve had. The taxonomic history of Acronictinae and Acronicta has involved much shuffling around of species, and I would like to see if we can sort out any more troublesome issues.
Larval description – One project of mine is to fully describe the larva of one Acronicta species to serve as my “atlas” for creating my larval character matrix. It might also result in a publication since it is a species whose larvae have never been described beyond a couple of sentences. I am working with A. falcula, an uncommon species which feeds on Corylus. The description will include a written morphological description, photography, habitus illustration, chaetotaxy (drawing of the hairs), SEM images, and life history information. It’s a charismatic little caterpillar. The drawings are currently underway, and I’ve got a specimen ready for the SEM later this week.
Behavior and mimicry – This part is the most fun! Many Acronicta species are aposematic and/or mimic other caterpillar species Mimicry in caterpillars is supposedly rare, but maybe it is just rarely reported? And why is mimicry so prevalent in this genus? Is it Batesian or Müllerian mimicry? Are the caterpillars chemically protected? Does their resting posture on their host plant offer any insights? Do they flaunt themselves or generally stay cryptic? To address these issues I want to raise several species and observe their behavior on their host plants in the wild or in a greenhouse. I want to try some bird exclosure experiments and use clay caterpillar models to test the effects of bird predation. I might also try offering them to ants to see if they have defenses against invertebrate predators. These experiments offer the possibility of some great collaborations with scientists from other universities.
And that’s enough for now!
Boreidae up close
Here is a boreid (snow scorpionfly) as mentioned in the previous post. This is as good as my little canon powershot could get… this individual is a female, note the ovipositor.
The species appears to be Boreus brumalis.
Last fall the Wagner lab was recruited to hunt down a few specimens in the family Boreidae, a small family of Mecoptera (scorpionflies). They are called snow scorpionflies due to their propensity for living in boreal or high altitude habitats, and their ability to thrive in very cold conditions. One or two species make it down to our area of Connecticut. We were told to look for them on snowy days in February and March, at the base of trees. Because they are generally only found under certain conditions, they are uncommon in collections. Our advisor had never captured one himself. I know we’re supposed to focus on moths… but none of us could turn down a challenge like this.
So, we all waited for snow. And waited. And waited. And…. waited. If you’re in the northeast you know what I mean… what happened to winter? I think we skipped it.
Finally a few days ago we got enough snow to coat the ground for more than a few hours. Hurray, we could go boreid hunting! So we piled into a couple of cars and drove out to our favorite collecting spot in the forest.
Marilyn and I were walking together and I mentioned that we should check the snow at the base of a nearby tree. As soon as we crouched down, she said “Hey, what do these boreids look like, anyway?”
Me: “Oh, about a few millimeters long I think.”
Marilyn: “Hmm, I think I see something, not sure what it is…”
Me: “Can I see?”
Marilyn: “Sure, let me catch it… uhh, do boreids jump?”
Me (upon seeing it in her hand): “Hey I think you got… wait… uh.. hmm… yes! Yes you got one!”
Having never seen one myself aside from pictures on the internet, at first I was unsure of my identification. Once I saw the mouthparts though, I knew we had one. Within the first ten seconds of searching. Awesome! Here is Marilyn with her prize:
A close up of the boreid itself:
So of course everyone else was disgruntled that they were not the first to find one (including me, I’ll admit), and we all scampered off into the woods to keep searching. Louis ended up finding two of his own.
It seems that when you disturb them they either jump, or play dead. Playing dead is probably pretty effective when you look like a little speck of dirt on the snow.
Now we have a few specimens to add to the university’s collection, which is pretty neat. I’ll keep my eye out for them whenever I go outside now, as long as we have some snow sticking to the ground.
I just sent in my application for BugShot 2012, an insect photography training course… I have heard a lot of great things about the course and the Archbold research station. Check it out!
Alex Wild is the fabulous photographer/scientist of Myrmecos, a blog which has caused me to really warm up to ants (even though they’re still annoying when they get in my kitchen).
One of my goals for my research is a complete larval description. Many species of insects are formally described based on their adult morphological characters, and the larval features tend to be secondary or omitted completely. In the case of the caterpillars in Acronicta, some of them have been well documented while others have been largely ignored. A complete larval description will help me learn important characters for my group and practice my photography, illustration, and SEM techniques.
I chose an uncommon species whose adults seldom come to lights, and whose caterpillars have not been described aside from a few lines in some field guides. Of course, being uncommon is going to make my job more difficult, but I do have some specimens and life history data collected last summer that I can start with.
The species is Acronicta falcula, a handsome caterpillar which feeds on Corylus plants (Hazel). Its common name is, predictably, the Corylus Dagger Moth. I have started drawing the chaetotaxy or setal map, in which I look at a specimen under the scope and try to draw the correct arrangement of hairs and other features on each segment. I am also attempting a life-like pen and ink illustration. So far I have sketched out the body plan, and I am adding the hairs as I complete my setal map. It is difficult to get the hairs right from the photo, and I want to ensure my drawing is correct. It currently consists of several layers of tracing paper, which will all be copied down in ink and shaded with stippling.
I also chopped up a specimen, dried it, sputter coated it, and am awaiting scope time next week to get SEM images of its various parts. I think the raised warts and hairs will be quite interesting.