Monthly Archives: May 2011

Servicing the caterpillars

Don’t blame me, I did not come up with that phrase… it’s certainly a source for jokes around the lab, though.

Here is a batch of caterpillars and eggs I’m tending to.

Exciting stuff, isn’t it? (there actually isn’t any sarcasm in that phrase on my part, I thoroughly enjoy this work, but I realize it’s not for everyone!) Every day I get to clean out their frass (poop), give them new leaves, measure their head capsules, collect shed head capsules if I can, get photos of different instars, and maybe even put a few caterpillars in vials of alcohol. And of course taking notes the whole time. As much as it is important to keep digital records, I enjoy scribbling down notes and sketches on paper. It keeps my mind more organized, and I like having everything in one place I can just flip through, instead of trying to hunt down files on my computer. I was inspired by a talk given by Michael Canfield at Harvard a few weeks ago – all about the importance and history of field notes. He’s written a book called Field Notes on Science and Nature – I have not read it yet, but I intend to. So far my notebook isn’t very thrilling, but I do have a few cute caterpillar sketches in there.

As an aside, notice the jar by itself on the desk, with the lid partway off… that’s my A. lobeliae female! She laid some eggs! Unfortunately, I had left her sugar water soaked napkin in there, which made the vial very humid. Caterpillar eggs do not like humidity, so I’m not sure if they’ll end up being viable or not. So she’s getting aired out, and kept a while longer, perhaps she’ll lay more.

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First to second

Acronicta afflicta in molting action.
(these photos are not of the same individual)

1st instar (note how it looks different from when it first hatched – it still has the same head size though!)

In progress… all the caterpillars which were molting were bright white, with almost no green coloration left at all.

And now for something completely diff…. uhh… second instar!

As an aside, their common name is the Afflicted Dagger Moth.
I wonder what they’re afflicted by?

Tufts

I was wondering when my Acronicta americana caterpillars would gain their characteristic black tufts – and I got my answer. The 3rd instar!

Aren’t they getting adorable? Their hairs seem way too long proportional to their body size, but they’ll grow into them. You can see the two sets of black tufts in the first half of the body, and one black tuft near the end. They’re not terribly obvious yet, but definitely there as black setae instead of white.

I couldn’t get a picture, but they also have interesting black/white patterns on their head capsules. Maybe soon I can find a way to brush the hair out of their eyes enough to get a good photo. This pattern will be gone as they get older and end up with totally black shiny head capsules.

New thought – I wonder if these will turn out white or yellow? Do they start out the color they’ll end up? Or could they change? We shall seeeeeee…

Luna update

The luna caterpillars are getting a little out of control… I have decided I am only going to keep 20 for now, maybe whittle that down to 10 as they get bigger. The rest, I am unsure of their fate, they will probably get mailed back to their collection locality, now that they’ve had a head start.

So this is my little crew of eating machines.

They needed a new container, something I can keep a branch of leaves fresh in, and also provide much more ventilation. So with some advice from my advisor, I came up with this contraption. I taped two containers together, cutting the top off of one and putting netting on top. I cut a hole in the bottom to put a stick through, and settled the containers inside a larger one, putting water in the bottom. The plant and a coffee filter (to catch frass) are now home to 20 adorable caterpillars gaining more colorful spines.

Black-light guest

Why hello there, Mr. Toad. Thank you so much for your services. You are diligently keeping guard beneath my black-lighting sheet, grabbing any little insects that come by. Well, almost any… you missed an elaterid (click beetle) over there. Just to the right a little bit.

Don’t be shy just because I caught you with my flashlight! I don’t think you can fit a whole Acronicta inside that little mouth of yours, so feel free to stay a while. I won’t miss a few mosquitoes or mayflies.

It seems toads can be common guests at black-lighting sheets – I remember encountering an adorable great plains toad cleaning up a sheet in Arizona. Do you have any black-light guest stories or photos? About toads or other creatures? Please share!

Give me a “J”

I have an interesting and perhaps ambitious goal – to photograph caterpillars posing in the shapes of letters of the alphabet. I do not know, yet, whether I want to try to have a consistent background or if I want to go for bright colors and contrasts. I also do not know how possible it will be to successfully wrangle caterpillars into, say, the letter “M”. It is not something I am going to lose sleep over, but I might try posing caterpillars with a paintbrush while I’m photographing them for other purposes.

Since I am studying Acronicta, I will at least be able to get the letter “J” pretty consistently. It is their characteristic resting pose, like this A. rubricoma. I was trying to photograph it against a white background when I realized it made the setae nearly invisible – but on the red paper, wow did the fuzziness pop!

What do you think? Do you think I should try it? Do you think it would work as a poster, sort of like the ones you see with butterfly wing patterns?

Got one!

I finally got an Acronita at my blacklight – a big female Acronicta lobeliae! As you can imagine I was SO EXCITED – I recognized the “dagger” markings characteristic of many Acronicta species right away.

Here she is in a container with a little bit of tissue soaked in sugar water. I watched her sip on the sugary mix, so she should survive for a little while. No eggs from her yet, hopefully will get some from her soon. I am raising some A. lobeliae caterpillars but only a few are thriving, so I’d really like to get some more from this girl.

Nature break

As much as I want to focus myself here, I cannot help but share some of the other creatures I come across.
The other day I went on a mid-day adventure with a friend to look for snakes.
Luckily for us, there are lots of places near campus to go exploring.
I got to catch my very first ring-neck snake, Diadophis punctatus! In fact, we saw four within half an hour. They are sickeningly adorable, and incredibly smooth to the touch. One of them half-heartedly tried biting me, they were all more concerned with slithering away. The temptation to bring one home as a pet was intense, but I resisted – I have enough snakes at home.

The other snake species we encountered was the eastern milk snake, Lampropeltis triangulum. And this one was NOT happy to be bothered. It was snapping, and rattling its tail. I love that behavior, I wonder if it’s a general snake defense that got brought to an extreme with rattlesnakes, or if colubrids like this are trying to mimic rattlesnakes? I think the first idea is more likely, but I haven’t read into it very much. Either way, it is alarming to hear a tail rattling against dry leaves. My corn snake does that in his cardboard feeding box sometimes!

And we saw some amphibians too. Puddles filled with swarming toad tadpoles, as well as some adult Bufo americanus. Who can resist a grumpy toad face?A pretty Rana palustris (pickerel frog), just because.And you didn’t think I could wander into the woods and avoid the insects, did you?
We came across a wonderful little clearing with dappled sunlight. Along the rocks and logs I saw tiger beetles basking. My friend tried hunting them with his net, and I tried hunting them with my camera. This went on for about half an hour… my little camera did a decent job, and it helped I was able to find a few that were more intent on basking/resting than getting away from me. I quickly got a feel for their preferred habitats and resting spots, and we were able to see several more during our journey through the woods.Eventually we figured we should get back to the lab… there are plenty of adventures yet to be had.

Acronicta afflicta – first meal

I have acquired eggs of several more Acronicta species from a collector, and a few have started to hatch.

The above video is a first instar Acronicta afflicta attempting to get at an oak leaf.
I guess I’m jumping ahead of myself though, here are the eggs!They look very much like the eggs of A. americana and A. oblinita, but with much rounder, more regular white spots. The first instar larvae look most like A. americana, being very pale and almost purple-ish. Perhaps these characters point toward evolutionary relationships? I would think so… I’m certainly getting inspired to get going on constructing the phylogeny of this group.There are many more eggs waiting… I’d say maybe 100 or more? I’ll be in the lab periodically over the weekend to check on them.

Molting – do not disturb

Go away, can’t you see I’m busy?This may be a puzzling scene, at first.
Caterpillars do not have regular eyes, but a series of stemmata. Up to six stemmata form arcs on either side of the head. Notice where the head appears to be… and where the eyes are. Something is up!

This Acronicta americana is in the process of molting, and it is working on releasing its head capsule.
They should not be bothered during this delicate process, as they are softer than usual and can easily be damaged.

Here is another individual, who had just finished the whole business.Check out that big head! It will take some time, probably a few days, for it to grow so its body is proportional to its head size. Then, when it’s ready, it will molt again, leaving a fuzzy mess behind.

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