BORING STORE
Guide to raising the giant silk moth caterpillar Hyalophora cecropia
The caterpillars eat A LOT! Make sure you have one of their preferred foods sources in abundance before hand. Once they eat a specific plant, they will eat only that plant. They like ash, birch, box elder, alder, elm, maple, poplar, wild cherry, plum, willow, apple, and lilac. See below for a links to where I bought my enclosures and other gear.
I raised them indoors under a window that I left slightly ajar. They got a little bit of dappled sunlight around 11am and indirect sunlight all day. It stays around 65-75° F, 24 hours a day.
The first instars are very small and can be raised in a smaller container. They don't need to be in a large habitat and would be easier to control in a smaller environment.
The hatchlings eat their eggs and will not start eating leaves until the next day or so.
The branches you collect should be soaked in warm water before placing in the habitat. You would be surprised what comes off of them! I found mites, spiders, bird poop, dust and evidence other caterpillars. Spiders will kill the first instars so be careful. Be mindful of where you get your branches. Pesticides will kill your caterpillars! Mine ate plum leaves.
Plum leaf
Newly hatched first instar - day 0 (May 29)
Each instar eats their molt and will not move or eat before and after molting for up to a couple of days.
Second instar - day 7
Third instar day - 15
Third instar color variant
Fourth instar - day 19
Fifth instar - day 40
The fifth instar eats A LOT. Mine were up to eating three, two foot long sprigs of plum twice a day for around two weeks before making their cocoons. Plus they make a lot of poop! I could not go out of town at this time.
Fifth instar growing into their skin - day 50
I only ever handled the fifth instar. They would actually climb onto my finger if I let them. They escaped a lot during this time while I was cleaning and filming them. They are very sticky and hard to remove from skin/branches/zippers. Also, I was allergic to them! Wash your hands before and after handling, and handle them as little as possible as it stresses them out. Don't touch your face or eat without washing your hands! You will also notice if you get up close they have a sweet smell. I am assuming this is sort of defense mechanism against predators and what causes the reaction.
Fifth instar. The colorful spikes are called setae and are meant to ward of predators. Caterpillars have true legs, which are the pointy ones near the head, and prolegs with blue sticky “feet” (also called crochets). The oval spiracles on the sides are how the caterpillar breathes.
I found that I did not need to place the sprigs in water. It was a pain to keep the water clean and they were wilting anyway. The caterpillars would not eat wilted leaves. The easiest way for me was to put the least amount of sprigs in the habitat, and let them all migrate to the new so I could remove the old. I would also move the sprig that the caterpillars were currently on out of the habitat and to clean it. This became increasingly difficult as they were near cocooning time. They became really fast and bold and spread out all around the habitat and would drape themselves across multiple branches. I was unable to clean the habitat to my liking the last two weeks.
They start making cocoons in the evening
Fresh, white cocoon in the morning - day 58
Cocoon starts to turn brown over the next couple of days. You can see them moving around in there!
Removed this new cocoon from the enclosure for observation
It took 17 days for the last of the 13 caterpillars to make its cocoon. I gently pulled the cocoons off the wall of the enclosure, as some made them right on the fabric, and cleaned all but one main branch off. In a large Tupperware I alternated paper towels and rows of cocoons. They will sit on a shelf in my house opened to the air until November, when I will put the lid on and place them in the refrigerator for the winter. I live in the San Francisco Bay Area where it rarely gets before 50° F, even at night during the winter. This species needs to experience near freezing conditions in the winter to successfully emerge in the spring. We will see these guys in eight or nine months!
Day 75 – all caterpillars in cocoons and placed in Tupperware (Aug 12)
All 13 hatchlings made it to the cocoons phase, which I was really surprised about as it is my first time raising moths from egg to cocoon. Hopefully they will all make it to the moth stage! Stay tuned to updates in the spring when these guys emerge. My hope is to get a poly tunnel set up in my backyard by then. This is where they will be allowed to emerge, mate, lay eggs and die. These moths are not native to California, so I will not be releasing them. Any future cocoons also would not be successful during the winter.
Growth
Feeding
Cocoon Making
Took Tupperware out of Fridge March 27
I could hear them wiggling around in their cocoons. I hadn't originally planned to cut the pupae out of the cocoon, but the suspense was killing me! I gently cut the outer envelope off the cocoon, and even gentler cut the inner envelope at the exit valve with dissection scissors. The side with the valve is obvious in the inner envelope as you can easily pull apart the cocoon and see the pupae. Inside was the pupae and the final molt of the caterpillar.
Outer and inner envelope plus discarded caterpillar molt
There were 5 female and 8 male pupae
Sexual dimorphism in the Cecropia pupae. Male is on the left and female on the right. The females are typically larger and slightly lighter and oranger in color. You can see what will become the antenna once it ecloses. The males have larger and longer antenna.
First male eclosed 35 days after being removed from fridge (May 1)
I was super bummed to have missed this guy coming out of his pupae. It happened some time between noon and 3pm. The second emerged the next day. I heard the pupae skin crack and he was fully out in less than 10 minutes. It took him around 1 hour to inflate his wings. When they come out of the pupae skin they excrete a beigish fluid (and if you handle them as well) that smells sort of spicy, but not at all gross. They tend to hold very still unless bothered, when they will slowly open their wings. They tend to act erratically when handled, and vibrate. They don't fly very well at this stage.
Eclosing
These are the eggs from one female.She laid them the day after mating. They should hatch in 10-14 days.
This is the enclosure I housed the adults in for mating and egg laying. The males fly a lot, especially at night. They really beat their wings up even in an enclosure this size.
The females lay eggs on the sides of the enclosure.
More eggs from a different female
The second year I used raising sleeves. I put them out on the tree once they were second and third instars.
Distribution of Cecropia in the US. If you live in the purple region you can safely release your adult moths. The white region does not have cold enough winters for their development in the cocoon. The moths will never emerge in the spring and would also be considered invasive in this region.
Glossary of Terms
instar - a phase between two periods of molting in the development of an insect larva or other invertebrate animal.
molt - (of an animal) shed old feathers, hair, or skin, or an old shell, to make way for a new growth.
cocoon - an envelope often largely of silk which an insect larva forms about itself and in which it passes the pupa stage, not the same as a chrysalis which is equivalent to the pupae of a butterfly, while in moths the pupae is located inside the cocoon.
eclose - emerge as adult from a pupae
sexual dimorphism - difference of size or appearance between sexes
