Cecropia Moth Project, 5 Months Later

Cecropia pupa

On October 26th we removed the cocoons from the refrigerator after exactly five months of winter simulation. The outer cocoons were very brittle, paper-like, and dry (you may recall they are made from leaves bound with silk). We read that it is OK to remove the outer and inner cocoons to get a look at the pupa, and naturally we were curious. After some research about the proper way to do this we got to work. 

One of the cocoons (outer)

Using a pair of fly-tying scissors, we trimmed back the outer cocoon. This part is relatively easy since the skin of the outer cocoon is so dry and brittle. It is important to keep the scissors as close to the surface of the cocoon as possible. If the pupa is punctured it could result in death. 

Here and below: The outer cocoon and inner cocoon

Next, the scissors were taken to the inner cocoon, which is covered in a layer of silk that feels like thin, dry hair. The cocoon itself is brittle but thicker than the outer cocoon. Cutting through the inner cocoon feels much like cutting a thick piece of construction paper. Again, it is crucial that this is done slowly and with great care. The scissors should stay close to the surface of the cocoon so as to not puncture the pupa. 

We felt movement almost immediately after beginning to cut the inner cocoon. The pupa shook and vibrated inside. Pretty wild. We proceeded slowly. Eventually we created a big enough opening to see inside, and there he was, writhing and wriggling. 

Inner cocoon cut open to reveal pupa

This particular pupa is a male, which we determined after seeing the large antennae. 

Pupa, antennae view

Pupa, rear view

Below is a video of the pupa in motion. 

After our success cutting open the first cocoon we decided to remove the outer cocoons from the three others so that everyone is on the same page. By doing this we also hoped to determine if the others are alive - and they are! After some harmless poking we felt movement from each inner cocoon.

We placed the four cocoons back in the aquarium where they started as wee black caterpillars. The aquarium is lined with brown paper and sticks are taped to the sides. When the moths emerge, they will climb up the sticks and hang vertically. We expect this will happen in the next week or two, so stay tuned.

Cecropia Moth Project, Day 99

The six weeks are up and it is time for the cocoons to go into the refrigerator for the winter simulation. After five months we will remove the cocoons from the refrigerator and wait for the moths to emerge. Take care until then.

The cocoons in a freezer bag, labeled with the date.

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.

Cecropia Moth Project, Day 24

4th instar Cecropia caterpillar, side view

Just a quick photo update to show the Cecropia caterpillars in all of their 4th instar glory. We still have nine caterpillars, and we've been able to find enough maple leaves to keep up with the demand.

4th instar Cecropia caterpillar, aerial view

Cecropia Moth Project, Day 20

It's day 20 and the Cecropia caterpillars are getting huge! We still have nine, and all but a couple are in the 4th instar stage. The 4th instar caterpillars have red and blue spines, and the further along caterpillars have a powder blue line along their backs. They are eating a lot, as usual, and it's interesting to watch them amble along the leaf edges with their new bulky bodies.

They are growing quickly, and we will drop more caterpillars off on a maple tree this weekend while collecting leaves.

Cecropia Moth Project, Day 17

3rd instar caterpillar

We are beginning to get rid of caterpillars as we can't keep up with their consumption habits much longer. We plan to keep three total (out of the 14). Yesterday we dropped five caterpillars off on a maple tree in Atwater Village. We kept the caterpillars on a small leaf that they'd been clinging to within the habitat, and we attached this leaf to the maple tree with string to ensure that it would not blow away. By the time we were done tying the string, one caterpillar had already moved on to the tree. In the coming weeks we will drop more caterpillars off until we are left with only three.

Caterpillar molting into the 3rd instar stage

Two of the remaining nine caterpillars have molted into the 3rd instar stage, and a third caterpillar is in progress as I type. The orange and powder blue spines are very flashy. You can see the shed skin and little popped off hat in the picture above.

Cecropia Moth Project: Day 15

Just a brief update to show how quickly things are changing. In a matter of two days, some of the caterpillars have taken on a greenish color. You can see a difference between the smaller, yellower individual on the left, and the fat, green guys on the right.

We have noticed that the caterpillars are much more interested in the green maple leaves than in the larger, redder ones. They have almost completely annihilated the green leaf we placed in their habitat, and they are now slowly moving to the redder leaves. We are going to try to collect more prize green leaves today.

Cecropia Moth Project, Day 13

2nd instar caterpillar. Resembles a school bus.

It is day 13, and almost all of the caterpillars are now in the 2nd instar stage. We are waiting on three stragglers who have been sitting motionless since yesterday, so they should be molting soon.

The 2nd instar caterpillars are eating a lot and growing quite large. They have developed black spiny bristles, which look scary but are actually harmless. Some caterpillars do develop poisonous bristles as a defensive measure, but these Cecropia caterpillars operate on pure deceit.

2nd instar caterpillars plus a small 1st instar. The arrow points to shed skin left behind.

We are beginning to get a sense of what to expect from future instar stages as far as consumption and size. We will not be able to sustain 14 of these gluttons, and we've decided that we will keep 3. The rest we will release onto one of the maples from which we've been taking leaves.

Cecropia Moth Project, Day 10

2nd instar caterpillar above two 1st instar caterpillars

Lots of updates to share on the 10th day of rearing.

Unfortunately, the small caterpillar that was having trouble clinging to leaves has died. There are now 14 caterpillars. This is still too many for us to feed once they get large, so we are going to have to figure out how to let some people go.

We changed the habitat as a result of problems we had with the previous setup. We got rid of the stick that we were using because it seemed to be housing an insect that was dropping eggs, and it also wasn't helping to keep the maple leaves fresh. We purchased water tubes used by florists, and made a simple stand out of a folded cardboard beer box (see photo below).  By keeping the maple leaf stems submerged in water, the leaves are staying fresh.

Aerial view of new set up

Water tubes, 5 cents each at florist

The big news: yesterday one of the caterpillars entered the 2nd instar stage. We were watching the caterpillars, staring really, then left the room for only a few minutes. When we came back, the caterpillar had shed its black skin and was a bright yellow color. In the opening photo, you can see the shed black skin bunched up near its rear - the caterpillars emerge out of their skin head first. It also appears that the shiny tops of their heads pop off when they do. You can see the caterpillar's little hat in the opening photo, just below the curve of its body.  Other sources have suggested that the caterpillars eat their old skin. We didn't see this happen, but the old skin is now gone (though the hat remains).

Minutes later, we witnessed a few of the other caterpillars stretching and writhing around. We were certain that we were about to witness another caterpillar molt. After twenty minutes or so nothing had happened, so we left them alone. Today they all remain in the 1st instar stage. Some of these caterpillars are getting very long and fat, so we imagine they'll be molting any day now.

Some remaining 1st instar caterpillars, looking terribly obese

Cecropia Moth Project, Day 7

Behold - the yellowing of the Cecropia caterpillar

Cecpropia caterpillars gathered together 

The Cecropia caterpillars are now seven days old. They have been splitting their time between resting and eating, and we see huge chunks of maple leaf being devoured. 

We've noticed that some of the caterpillars seem to be more social than others, gathering closely together on one leaf to eat and rest.

While most of the caterpillars are growing and taking on strong yellow highlights (almost time for the 2nd instar stage), one little guy seems to be struggling. He has fallen off of leaves several times, and he's much smaller than the others.

Another issue we're having is the stick that we placed in the habitat. We noticed a small hole near the end of it, and it appears that some kind of woodboring insect is living inside. Several inches down from this hole we found some miniscule oblong egg-type things that had dropped from another opening. We are going to remove the stick and the eggs, and also stop using the dirt. It seemed like a good idea, but in both cases - the dirt and the stick - there may be something living inside that could kill the caterpillars or spread disease.

Cecropia caterpillar, taking on yellow highlights

Cecropia Moth Project, Day 4

We were able to find a new habitat for the 1st instar caterpillars, so now there will be plenty of space to move around when they get large (Cecropia caterpillars can grow to be the size of a human finger).

We filled the fish tank with dirt to combat the frass issue. It's either regular frass cleanings or sporadic dirt shiftings, so we went with the dirt shiftings. We also put a branch inside and lined it with the maple leaves. We're trying our best to simulate a natural environment. We included another wet paper towel at the bottom of the tank to keep things moist.

Today consisted of a lot of lounging around for the caterpillars followed by some gorging. We noticed that a few are starting to take on a yellow color, which may mean they are getting ready to ecdyse into the 2nd instar stage. They are now four days old.

Cecropia Moth Project, Days 1 and 2

Cecropia caterpillar, 1/4"

Once the eggs hatched we found fifteen 1st instar caterpillars, and we were eager to get food to feed them. Normally, the eggs are laid on the host plant and the caterpillars feed on that. We read that the host plant for Cecropia moths is the wild cherry tree, but we could not locate any in our area. The caterpillars will also feed on ash, birch, box elder, alder, elm, maple, poplar, plum, willow, apple, and lilac leaves.

Initially we could not find any of these trees. It could be because most of these trees are deciduous, and do not have any leaves this time of year. We tried feeding the caterpillars a number of other leaves including eucalyptus, asian pear, blueberry plant, blackberry plant, lemon tree, hawthorne, and countless others that we weren't able to identify. With each new leaf that was added to the container the babies became active and began to explore, but they quickly lost interest. The first bites we saw were on the eucalyptus leaf, but it seemed they were sampling rather than actually feeding. In all cases they abandoned the new leaves and returned to climbing up the sides of the container, eventually congregating at the top.

Almost 48 hours after the hatch, the caterpillars still hadn't eaten. We became nervous thinking that we might not find any suitable food. We drove around and finally located a maple (one of the trees listed as part of their diet). We attached the leaves near the top of the container, hoping that since they head to the top anyway they might incidentally land on the leaves. We also added a moistened paper towel to the bottom of the container, as we read that they will not feed if their environment is too cold or too dry.

When we woke up this morning we found that the caterpillars had eaten the maple. There is also a noticeable amount of frass (caterpillar feces) on the bottom of the container. Very exciting. Today we will try to find a larger container and collect more maple leaves. 

Cecropria Moth Project

On February 2, Oliver found this moth clinging to the side of a building at Calamigos Ranch in Malibu. He brought it home because he thought I would like it (I did). We identified it as a Cecropia Moth (Hyalophora cecropia), North America's largest moth. This particular species has an adult lifespan of 7-10 days. Flying only to mate and lay eggs, it does not even have a mouth.

Oliver placed the moth in a plastic container for transport. These moths release eggs when they are about to die, and we found a number of eggs stuck to the sides and bottom of the container when Oliver returned home. The moth died about an hour later.

We kept the eggs in a tightly sealed container punctured with air holes, and they sat unattended in a shady corner of our house for sixteen days before hatching on February 18.

Cecropia eggs