This Cecropia caterpillar is stretching into a nice pose just after molting into the third instar phase. It's coloration is still pale -- the pedicles supporting the spiny protective hairs haven’t darkened yet, and the “eye” patches on the head have yet to appear. 

The white breathing holes (spiracles) are clearly visible in this picture, between the black spots on it’s side.

I caught this caterpillar working out of it’s old skin, begining the third instar phase. I came across it well into the process, but it still took several minutes to finish. It seemed to expand and contract it’s body in waves to push the old skin back and off. It finally cleared itself completely by curling into a tight “C”, pulling it’s rearmost portion out of the old skin.



I’m constantly amazed at the details I see through the camera when doing macrophotography. 

I’m quite often surprised again when I edit the images! This series of shots, as the caterpillar worked it’s way out of it’s old skin, is one good example.

Looking through the images at full size, I noticed the claws of the “real” front legs were still on the shed skin.
I had assumed only the skin was shed, but I see that the outer layer of the claws shed off, too! 

The following six pictures are enlargements from portions of the full size images.

I was also surprised to find a mite crawling around on the shed skin as the caterpillar was working it off. 

I don’t know if the mite is a parasite of the caterpillars, or if it just happened to be there -- or if they feed on the discarded skin. But, I will be looking for them in the rest of the images!

This is the same mite, later in the series of shots, as it crawled off the shed skin onto the lilac leaf the caterpillar was on.

Did you also noticed what looks like fine hair on the surface of the leaf? They lay flat, though, unlike a leaf's  protective hair. These are fine silk threads spun unto the leaf's surface.

They may have come from the caterpillar, though I didn't see them prepping the spot before shedding their skin.

More likely they are the anchor threads of small spiders that travelled the leaves before I brought them in from the lilac bushes.

The tiny claws of the rear prolegs are snagged onto them, making a good anchor to help pull the old skin off.

Here's a closeup of the head -- another crop of one of the full-size shots. You can clearly see the mouthparts and feelers that help guide the leaf into the serrated mandibles. The mandibles don't chew the leaf, but cut it into small crescent shaped pieces to be digested in the stomach. 

The 5 simple eyes on this side of it’s head can also be clearly seen, since the black "eye spots" haven't developed yet. 

Notice the pink, out-of-focus "blob," on the caterpillar's head -- just above the jaws in the shot above? The fast travelling little mite has found its way back onto the caterpillar. ...an unintended guest that came in with the leaves.

Here's how the late second and early third instars compare in size and coloration. 

The third instar certainly looks more striking -- and formidable! The colors of the pedicles have darkened, the "eye" spots have appeared and the bright body color and four red pedicles behind the head stand out as a warning to larger predators.





Stay tuned for the next in the series, as the caterpillars continue to grow and begin to molt into the even more colorful fourth and final instar!


Please feel free to comment & let me know what you think of the series so far!

After the caterpillars hatched and began to grow, I wished I had counted the eggs; they didn’t move nearly as much as the caterpillars! While I can’t say for sure how many eggs were laid, there were around 100 caterpillars, between those I released and the ones I kept until they spun their cocoons. 

As they began to grow, and eat so much that I couldn’t keep them fed throughout the day, I experimented by adding Maple leaves as a different food source. But, they didn’t touch them -- unless you count walking across them to more lilac leaves! I knew Maples were one of their preferred foods, but apparently they have (or prefer) to remain with one food source, once they’ve begun on it.

To prevent underfeeding them, I let a couple dozen at a time free into the Lilac bushes in the yard. I repeated the earlier experiment by letting one caterpillar go in a Maple tree, but after checking on it over several hours, it still hadn’t eaten anything. So I brought it over the Lilacs, too.

The cecropia larvae grow through 4 stages (or instars) between hatching and spinning their cocoon. They pupate over winter and emerge as adult moths the following summer.

Here is a brand new second instar Cecropia caterpillar just after molting. The old skin is momentarily caught on a protective spine at its back end.

For comparison, this image shows the first two stages -- a late first and early second instar. 

The second instar is certainly more colorful, with stouter pedicles supporting the protective spines.

If you look closely, you can see a row white spots on both of these caterpillars' sides. These are the spiracles, where air enters into their respiratory system.

Adult Cecropia moths have no mouthparts or digestive system and only live a few weeks after emerging from their cocoons.

While I let her go shorty after she had laid her eggs in the terrarium, she didn’t lay any more and didn’t fly off. So I brought her back inside. She died shortly afterwards, but I was able to get some close-up images showing the scales on her wings and a detailed shot of her head, showing the lack of mouth parts.

My next post (the forth in this series) will show the caterpillars as they molt into their third stage. The third instar has fewer black spots, and four of the pedicles near its head grow larger and turn red.