Category Archives: Comachara
I keep a notebook of everything I do at the lab. All measurements, observations, etc. Every few weeks I go through and transcribe my notes into detailed rearing notes in an Excel file for each lot (the caterpillars are in numbered lots to keep track of them). Right now I’m due for a good long note deciphering session, so to procrastinate from that, I give you… some sketches…
These are from early on, when my first batch of A. americana and A. oblinita were in their eggs. It seems like the flat edges around the eggs are used to hold their extra long setae.
This sketch is of an early instar Comachara cadburyi. They were green with white stripes – at this point they were finally starting to look like caterpillars and less like tiny lumpy green maggot-ish things.
A neat observation – a young A. americana was perched upside down on the wall of the container. It had to poop… so… it bent its body so its abdomen was dangling out in the air, and dropped a piece of frass to the ground. Little guy was conscious of not dropping frass on itself. Too funny!
I wish I had more time for sketches like these, I tend to write quite descriptions of behavior and move on to the next creature that needs my attention. We’ll see what inspires me next.
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!
One of my major goals is to rear caterpillars from eggs in order to track their life histories – number of molts, sizes of head capsules, any variation in coloration or behavior. I am attempting to collect my own females to get eggs, so far with no luck. However my advisor has gotten some females to lay eggs for me, and I have a few batches on the way from other collectors.
Here are the eggs of a relatively drab, unassuming little moth, Comachara cadburyi (Cadbury’s lichen moth). It is in the subfamily Acronictinae, and it is very rare for them to lay eggs in captivity. Out of a handful of females, only one laid for us, but wow did she do a great job. For a sense of scale, those are her own wing scales stuck to the eggs. The eggs were barely the size of an “o”, this image was taken through a scope with automontage software.And after about a week, they hatched into approximately 50 adorably tiny barely visible caterpillars. Now, there is a bit more of a story to this. I was away for the weekend, figuring not too much could happen in two days. Right? Wrong. All three of my egg lots (this species, and two others) hatched! My advisor was gone for a few more days, so I was thrown into a panic. I don’t know my trees very well yet, and the field guide gave so many options for each, I didn’t know what would be best to pick. Luckily, another student was working here, whose mother studies plants. I was able to follow them to their house to collect the three plants I needed… after much rushing around, I was finally able to transfer the larvae into new containers with food, and they happily settled in.
Here are a few of the caterpillars, starting to feed on Nyssa sylvatica (black gum). This leaf was about 1″ long. Notice the feeding damage – when caterpillars start out this small, they can only eat through one layer of the leaf, leaving little “windows”.They’re slowly growing and thriving, if I’m lucky I’ll get to rear them all the way through!