Cecropia Moth Project, Day 55

Cecropia caterpillar cocoon

All four caterpillars have pupated and they are now silking away inside the cocoons (we can hear them working). The cocoons are very hard and the caterpillars will continue to add more layers of silk over the next six weeks. After this six weeks of work we will place the cocoons in the refrigerator to simulate winter for five months.

Cecropia caterpillars cocoons tied to a string

Cecropia Moth Project, Day 51

This past week we started to get worried that something was awry in caterpillar world.  After looking again at the other Cecropia blogs that we've been referencing throughout this process we realized that our caterpillars had long passed the five week mark when they should have started spinning cocoons. Our caterpillars were nearing seven weeks, and we noted that they'd become less active and that their frass size and output had decreased. Our immediate concern was that we'd given them a disease by touching them (you are not supposed to touch the caterpillars without first thoroughly washing your hands, as bacteria is transferred easily to the insects). While we'd generally taken precautions there had also been times when we hadn't.

Our concerns were quickly laid to rest when we returned home yesterday afternoon to find that one of the caterpillars had taken a giant frass, expelling a large amount of water in the process. We'd read that this is what happens before they are getting ready to pupate, as they will be locked away for months unable to empty their bowels. Interesting to note is that the caterpillar was hanging completely vertical from a twig, holding on with only its front (real) legs -- the first time we'd ever seen this behavior. The front legs do not have grippers like the prolegs, so it seemed odd that the caterpillar would be dangling in this way that to us looked rather precarious.

Holy frass!

Red arrows point to front legs, blue arrows point to prolegs

Within an hour the caterpillar had gripped back on entirely and moved to a different location in the habitat. Later last night we found that the caterpillar had started spinning (!) and pulling leaves in around it (we padded the habitat with additional leaves knowing that the caterpillars piece the cocoon together by pulling in leaves). This morning we woke to find a tidy looking albeit half finished cocoon. Exciting.

We imagine that we'll be seeing more frassy messes and cocooning in the next day or so. 

First cocoon

First cocoon, another angle

Cecropia Moth Project, Day 47

5th instar Cecropia caterpillar

The Cecropia caterpillars continue to grow, and they'll likely start spinning cocoons any day now. We are still waiting for the front horns to turn orange as we've seen on other 5th instar Cecropia caterpillars. Perhaps this won't happen. If it doesn't, we'll be curious to know why. Maybe diet?

New habitat arrangement

We changed the habitat once again to accomodate the caterpillars' desire to hang and their eventual need to spin. We drilled holes into a small wooden board and placed the water tubes and additional sticks within those holes. We are keeping the habitat flush with maple leaves. If caterpillars had emotions, I imagine they'd be happy with the new arrangement. They are quite active and eating a lot.

Cecropia Moth Project, Day 39

No real updates to share other than a dramatic episode from last night. A bit of a traffic jam occurred atop one of the leaf stems, and this resulted in some unfriendly poking, prodding, and theatrical writhing by the caterpillars. Ultimately the jam was cleared up, but not without these initial fisticuffs.

Cecropia Moth Project, Day 36

5th instar Cecropia caterpillar 

As we suspected, the caterpillars molted again! We're a little confused about what this means. Are they still in the 5th instar stage? Do they change twice in the 5th instar stage? We need to do some research.

Unlike with previous molts, the caterpillars' appearance was nearly unchanged after this molt. However we did note more pronounced black spots on the tail horns and an angling of the back horns. The suctions on the feet are also much larger.

Bottom caterpillar is mid-molt. You can see that the yellow spikes don't have black rings or spots yet. These develop over a few hours.

I was able to capture video of the last parts of the molt, during which the caterpillars shed their skin.

Cecropia Moth Project, Day 33

Two 5th instar Cecropia caterpillars (one further along) before we released them on to a maple

This past weekend we finally decided to release more caterpillars into the wild. Despite the fact that we found a good way to collect leaves, we still couldn't keep up with their eating habits. We let five off onto the same maple tree in Atwater Village where we released the previous group.

We now have four caterpillars who remain in the 5th instar stage. Unlike other 5th instar caterpillars we've seen in our research, our caterpillars are not yet exhibiting orange frontal horns. We are wondering if this means that they will be molting again, or if they will just continue to change in color as they grow.

Some changes we've noticed include: increased feeding that happens in short, hasty bursts, increased frassing (we change out the bottom paper towel every day or so), and a new interest in hanging upside down from the underside of the cardboard leaf stand. They hang like this whenever they are not eating.

5th instar Cecropia caterpillars hanging upside down. Apologies for the bad picture quality.

Cecropia Moth Project, Day 27

5th instar Cecropia caterpillars, bursting with flavor

Most of the Cecropia caterpillars are in the 5th instar stage now, with bulbous yellow horns and plump blueish bodies. The transition into this stage is pretty dramatic - the caterpillars shed a gross brownish layer that bunches up near their rear quarters (shown in the picture below).

5th instar Cecropia caterpillar with shed skin

As the caterpillars have grown, so has their frass. It is large and we are regularly clearing off the water tube stand and bottom paper towel.

5th instar Cecropia caterpillar flanked by two 4th instar fellows. This photo was taken two days ago and the 5th instar caterpillars have since taken on a bluer hue and rounder body shape (as shown in the other pictures).

We have a new technique for collecting maple leaves and we haven't been worrying so much about keeping up with the feeding. Oliver uses a welding rod to reach up and pull down small sections of branch that we place in a cup of water after returning home. We then pull individual leaves off as needed and place them in the water tubes. It's a great method, allowing us to collect more leaves at once. However, Oliver looks like a bit of a criminal creeping around residential streets at night with what looks like a crowbar in hand. If you're going to use this method, don't get shot.

5th instar Cecropia caterpillars. The one on the right is further behind.