Monthly Archives: June 2011
Technical difficulties
Fell off my bicycle yesterday. Actually, spectacularly flipped over my handlebars while going fast downhill in the rain on a bumpy unevenly paved road. Was only about 2 minutes into the triathalon I was going to attempt with my friends… oh well.
My boyfriend took great care of me, he’s the best. Got me to the ER, they saw me right away, wonderful people there. X-rays showed a fractured scaphoid bone in my wrist. Temp splint now, need to make an appt to maybe get a real cast.
Typing is difficult, so I won’t be doing much blogging for a while. Maybe put up some photos now and then with quick updates.
Should only be about a month before I’m fully healed, so I’m hoping I can be patient and not go crazy by then.
Wish me luck!
Zombie
I was gathering maple leaves for my caterpillars when I noticed this inadvertent hitch-hiker and its cargo. The caterpillar is Amphipyra pyramidoides (the copper underwing)… and this photo tells a little story.
Microgastrine braconid wasps are parasitoids, specializing in caterpillar brain control. I’m having a tough time digging up exactly how it all works, but basically it goes like this: a female wasp finds a plump caterpillar and lays an egg in it. The wasp larva hatches and eats the caterpillar from the inside, but not so much that the host dies. When it is ready to pupate, it emerges from the caterpillar (in the photo above the emergence hole has left a brown scar) and pupates underneath it. Now this is the bizarre part – the caterpillar faithfully protects the pupa!
Even, as you can see, after the wasp has emerged.
Poor caterpillar – forced to protect the wasp and not move from its perch on the underside of the leaf. Not feeding, not growing, simply waiting to starve to death. No amount of prodding would convince the caterpillar to leave its post. I put it outside, hopefully to serve a further purpose as food for some other creature.
Wardrobe change
Unfortunately, my beloved Acronicta afflicta all came down with some sort of disease or virus, which made them die during molting and threw their digestive systems out of whack. It was a very sad few days for me as I watched them succumb to the sickness, but I took the opportunity to preserve a bunch for further research. That was my ultimate goal, anyway, but I sure was hoping for a few to make it all the way to adulthood. If I’m lucky I’ll get another batch of eggs this summer to raise!
Anyway, here is what I think is so great about A. afflicta. Would you really think these are the same species? The first is a 5th instar, the second is a 6th instar.
Pretty dramatic!
Balls
This post is about balls. Of wood. Created by caterpillars. Not what you expected, eh?
The story starts with the species Comachara cadburyi, the eggs and youngsters of which I introduced back in this post. I have not given any updates on them because their development has been fairly uneventful – growing into larger green and white caterpillars, gaining a few more setae along the way.
Finally they were looking prepupal – usually characterized by a slight color change. A few had gained light brown chevron markings, so I put a piece of soft wood into the container (many species in the subfamily Acronictinae burrow into wood to create a pupal chamber and safely pupate).
The next day, this is what I saw:
Uhhhh…. what? Is that really my green caterpillar? The rear end is on the right, the front end is on the left buried in the bark.
Note there was no molt to obtain this color change – it is the same size, the same instar. One individual can change from green to brown in order to become less conspicuous as it spends several hours digging its pupal tunnel.
That’s not all folks! I took a look at the bottom of the branch, and saw another caterpillar digging. But this one wasn’t nearly as brown, in fact it was just the right shade to blend in with the pale pulpy wood it was sitting on.
How crazy is that!? I wonder how a caterpillar can determine the color of the wood it’s sitting on? Caterpillars don’t even have proper eyes, with stemmata instead of the usual compound eyes or ocelli. I was able to watch two burrow into the bark with dark coloration, and two burrow into the pulp with greenish tan coloration.
That’s not the best part, though. This is how it’s done.
Wood balls! And now, in action:
It was fun watching the caterpillars digging and throwing their perfect little balls of wood, sometimes getting flung as far as 6″ away.
And finally… the entrance all sealed up. Unfortunately I missed the last turn around of this one (they back in so they can seal up the tunnel behind them), but I was able to spot the entrance. Caterpillars have spinnerets in their mouths, and use the silk for a variety of purposes. When they are young they can use the silk as a safety line, before each molt they create a mat of silk to cling to, and when they are ready to pupate the silk comes in handy for securing themselves to a potentially precarious substrate. In this case, it has been used to adhere a piece of bark to the tunnel entrance.
So now I just have to keep an eye out for emerging adults!
Dancing caterpillar
I don’t really know what’s going on here. Acronicta afflicta, fifth instar. Video was taken through a dissecting scope by an undergrad in the lab while I was away last week. Turns out most of these were pretty sick (most are dead now, only one has made it to the 6th instar so far)… so perhaps this was an early stage of the illness? Or just a post-molt behavior as its body plumped up?
Either way, it’s a little silly.
“Does this look weiner-y to you?”
Many strange things are said in this lab.
Apparently my advisor told one of the undergrads to find a picture of a caterpillar in his slide collection. He gave the species and said to find a pose that looked “weiner-y”. Really? I mean… I know caterpillars can look somewhat phallic… but… gahhhhhh. I was then asked, of course, by the student to verify his findings. “On a scale of one to ten, how weiner-y would you say this is?”.
Sigh. I love dirty innuendos but around here I feel like I have to play the part of lab mother, with a short sigh and raised eyebrow of disapproval… otherwise things will get out of control. It’s all fun though!
We have a section of the white board saved for quotes. Could be from anyone. You never know when something you say will get scribbled on the board. Here is what we have up right now:
“Reuse, recycle, redecorate” (Referring to my crafting break where I cut up American Entomologist covers to make a collage to cover the back of a bookshelf)
“It’s really hard to get eggs out of a male” (My advisor had caught some Acronicta at his blacklight and brought them back alive so they’d lay eggs, thinking they were females. To teach me how to sex moths, he knocked one out with a bit of cyanide and had me gently squeeze the abdomen. The claspers opened wide – guess it was a male!)
“Kill him first, ask questions later” (me) (I don’t remember why I said that)
“When Brigette’s bad, just sharpen a pencil” (Our electric pencil sharpener squeals like nails on a chalk board)
“Oh this is a good position, I just LOVE this position” (Preparing a caterpillar to photograph)
“Oh yeah! Look at that rump plate!” (Looking at slides of caterpillars)
The quote section is growing slowly over the summer, since less people are around. Once the semester starts in the fall, there will probably be a few gems every day.
Hungry
My A. americana caterpillars sure can eat!
(That leaf is not A. rubrum though, I’ve been feeding them all sorts of maple leaves)
They have been one of my favorite species from the start. First of all, their eggs were much larger than the others, and they hatched almost twice as large as the other caterpillars I’m rearing! At first I thought it must be a mistake, but indeed, I had measured them just after they hatched. They have always had big adorable heads, and of course now they are piling on the fuzz. They are in their fifth and sixth instar now, I wonder how many instars they have total? I am starting to consolidate my notes and measurements and photos, creating a panel of images to show the changes as they grow. It’s satisfying to already have some “results”.
And more eggs are on their way! A few species I have not reared yet. So now that my current babies are getting older… time for a fresh batch of eggs and hatchlings. I’m certainly going to keep busy this summer.
Bad hair day
I woke up this morning feeling a bit like this guy.
This is one of my Acronicta americana, in its fifth or sixth instar. Very scraggly looking, missing a few black tufts… hopefully if he molts again he will get fluffed up back to normal.
Luckily for me, I can brush my hair and throw it under a bandanna. This guy has to parade his appearance around all the other pretty caterpillars… oh well. He’s got some company, at least one other individual is missing his second set of black tufts altogether. That one is in the middle of a molt, so we’ll see what happens next.
Mega
A couple nights ago it was raining, as usual. I kept my blacklight on, though, since it was just sprinkling on and off. Only a few moths came to the light, along with a smattering of beetles. I was about to give up and go to bed when I saw this lovely lady buzzing around. WOW!!!
She is Megarhyssa atrata, the Giant Ichneumon, and take a look at that ovipositor! Female ichneumonid wasps such as these use that long contraption to bore into wood and reach a soft squishy insect target inside, usually a horntail wasp larva. They will then lay an egg inside the larva’s body, and the young will hatch and eat it from the inside out.
I had never seen one of these alive before, and pinned specimens are usually beat up and broken. I was so impressed (and sleepy) that I decided to let her live (hey, I keep a kill jar by the door for times such as these). However when I opened the screen door to go back in the house, she followed me in! So we played a game of tag around the lights in my living room for about 10 minutes, with her pretending to sting me every time I got my hands on her… until I finally wrangled her safely and threw her outside. She bounced off my blacklighting sheet a few times and fluttered back into the woods. Definitely an interesting encounter.
Neat and tidy
When you’re a caterpillar, you need to keep your living space tidy. Don’t want parasitoids to find you, or for poop to get stuck in your spines!
So if you’re feeling lazy, you need to get creative.
(Be sure to watch to the end)
caterpillarblog 