I often get questions about how to raise caterpillars. One of my first jobs during college was raising caterpillars, which lead to similar jobs throughout the years. Why raise a caterpillar? Not only does successfully taking care of another living thing lead to insights into its biology and behavior, but also when a beautiful butterfly or moth emerges, it is an amazing experience.
A few weeks ago I wrote a post about white-lined sphinx moth caterpillars.
In the update I mentioned that I had placed a caterpillar in a terrarium with moist potting soil (about five inches deep). The caterpillar immediately disappeared, but I knew where it had gone. Large moth caterpillars, like white-lined sphinx moth caterpillars or tomato hornworms, dig into the soil before pupating. Their pupa looks like a dark reddish-brown cigar. Saturday I found the moth sitting on the cloth I had used to cover the terrarium. It had successfully emerged.
Here it is.
Because white-lined sphinx moths are big and active, they need a lot of nectar to keep them going. After taking a few pictures, I immediately let it go. Here’s a link with some amazing pictures of white-lined sphinx moths. This entire website is full of great information and photographs.
What do you need to raise caterpillars? It does depend on what kind, but here are some general guidelines.
1. Unless you are using a kit that supplies special food, you will need large quantities of fresh plants. And not just any plant, most caterpillars will only take one or a few kinds of plants as food. Once a tiny larva has started eating one kind of plant, they often will refuse to take anything else, even if other members of its species will. A good rule of thumb is only bring home caterpillars that you are absolutely sure you know what they eat, and you have lots of those plants available to feed them. Edit: What white-lined sphinx moth caterpillars eat.
2. Provide a clean, safe container covered with screen or cloth to allow for air circulation. It is best to keep the container outside in as natural conditions as possible. Insect life cycles are extremely sensitive to light and temperature. If you bring the critter inside where it is cool and dark, it may emerge days or even weeks after wild members of its kind and may miss critical windows of opportunity to perform necessary behaviors like mate or migrate.
3. Keep only one or a few in a container. Crowding insects into small containers greatly increases the chances for disease. Insects can get viruses, bacteria and fungi, which can make them sick, just like those things can make humans sick.
Scientists have suggested that monarch butterflies may migrate because of a parasitic infection. This parasite (a protozoan) causes the butterfly to be weak but not die. By going on long migrations, the sick individuals are left behind. When we handle monarchs, we risk spreading the disease even more. Let me know if you’d like more information about this.
4. Provide sticks for butterfly caterpillars to climb on when they are about to make their chrysalises. Moth caterpillars will need plenty of moist soil to dig into. Other caterpillars may like to have different substrates to pupate in, like cloth or egg cartons.
5. Insects are also sensitive to humidity, especially when they are molting. It can be tricky, but try to keep the humidity up without getting the container too moist. Too much humidity can cause things to get moldy.
I hope these guidelines doesn’t sound too negative. Having a lot of experience, I have a better idea of all the things that can go wrong and I wanted you to avoid the problems. And oh yes here’s one more: don’t leave the lid off the container once the caterpillars have pupated. My son did this, and we had cabbage-looper moths all over the house. (It was actually a hoot!)
One great way to raise caterpillars is to plant butterfly and moth plants in a butterfly garden. (Check out an earlier post on butterfly gardening.) Then the caterpillars do all the work themselves.
Also, don’t forget to take a look at some of the butterfly and caterpillars books for children.
And finally, my friend Debbie called again. Her passion vine plants now have gulf fritillary caterpillars on them (see last week’s post for details).
Hello, I saved a white-lined Sphnix moth from a spider web in napa valley, california. I was very careful not to touch it with my hands and the moth appears to be fine. I have set the container outside to set it free several times now, and though it seems to be fine, it doesn’t appear to have any interest in leaving.
Is there anything I can do to feed/take care of it until it decides to take flight?
Thank you!!
Sorry, I did not see your comment yesterday. Do you still have the moth?
Usually moths will enjoy a little sugar and water mixture, about the same ratio of sugar to water as for hummingbird syrup, which is one part sugar to four parts water. Or you can offer it a flower.
Good luck!
I found a rather large sphinx moth caterpillar sitting on top of some weed ground cover. I’d like to keep it long enough for my kids to see the transformation and then release it. It’s very large so I suspect it should be about ready to go underground soon. I’m not sure what it’s been eating. What would you suggest I do to ensure its survival?
Toni,
Because the caterpillar is large, I think you are probably right that it is ready to pupate. I would put it in a container with a few inches of moist potting soil, about the moisture level for a potted plant that has dried out just a little. You could add some of the weeds it was on, just in case those were the food. If it doesn’t either start eating or start digging in by tomorrow, you might need to find out what kind it is to supply the correct food.
Have you tried a Google image search? Google “sphinx moth caterpillar” and what color it is, and see if you can find a similar one.
The caterpillar is most certainly a white lined sphinx moth. I put it in a container with a few inches of potting soil. I tried putting some of the weeds in with it that I found it on and it ate them all up. I’m happy to say that it seems to be thriving. It’s been eating and pooping quite a lot for the last couple of days!
Congratulations on figuring out what it is and what it eats, Toni. Glad to hear things are going well.
I found a large Great Ash Sphinx caterpillar and brought him inside. I immediately put it inside a container with about 5 inches of dirt. Right away, he began to burrow. I’m curious as to how long he’ll stay underground in his pupate stage. And as far as keeping the soil properly hydrated, how would I manage that without drowning or dehydrating him?
Julian,
What a great find!
As for how long it will take to emerge, it depends a bit on where you live. There are two broods in the south, so you may have caught the tail end of the first brood. If that is the case, it might come out in a few weeks (although it will depend on the temperature). If it is the second brood, it may overwinter in the pupal stage and come out next spring. If it doesn’t come out by the end of August, I would hold it in a protected area where it could get a chill but not freeze, like an unheated garage or basement.
Keeping the soil moist, but not too wet is important. Do you have a mister or spray bottle, like for plants? Check the soil with your finger and if it starts to dry out, mist it lightly. Because different soils hold water differently, you’ll have to experiment with it a bit.
Good luck!
I was so surprised when I found it, cos the color is gorgeous, and I’ve never seen one like it. But he was climbing up the side of a brick wall outside my building. It confused me a little bit. I reside in New York, in the Five Boroughs. Queens, to be exact. So hopefully that will help figure out how long. And I actually do have a simple spray bottle I can use, so that’s definitely covered. I greatly appreciate your help on this!
Julian,
You know, they call the phase when the caterpillar crawls around looking for a place to pupate the “wandering phase.” Sounds like yours really wandered!
It would seem likely that it would stay as a pupa over the winter there in New York, but who knows what it will do now that you brought it inside.
I forgot to mention, you should put in a pencil or thin stick for the moth to climb up when it emerges so it can hang properly to dry its wings.
Hi, I couldn’t help but see that you’ve helped some people raise their caterpillars and moths. I got a sphinx caterpillar off my grandma’s tomato plant about 3 days ago, its already buried itself in soil in the glass jar I put him in, I actually put him inside but then I was worried he wouldn’t get enough light so I put him back outside in a shady but warm spot… I live in New Mexico and this week should be in the 90s , so what would be your opinion on it emerging as a moth this summer, and should I unbury it once its made its pupa or leave it alone, because he’s dug pretty far in the soil. I wanted to make sure its wings don’t get deformed. Any information will help! Thanks!
Ashley,
Light isn’t a problem when the moth is in the pupa stage. A caterpillar on a tomato plant might be the tobacco hornworm http://blog.growingwithscience.com/2010/10/tobacco-hornworm/ It is very likely to emerge this summer.
No need to dig it up, just keep it moist. Is the jar big enough to put in a stick or pencil so that the moth can crawl up and hang while it is drying its wings?
The Manduca Project has a lot of information about taking care of those caterpillars/moths.
The white lined sphinx moth I caught ate a ton of the weeds I’d found it on and yesterday morning I found it had dug under the dirt to pupate. About how long can I expect it to stay under there?
Thanks!
Toni,
Great that your caterpillar pupated.
How long it will stay a pupa depends a little bit on where you live and what temperature it is, but white-lined sphinx moths have a couple of broods a season, so it will likely be out in a week or two. You can just leave it in the soil. Did you see the part about giving it something to climb on when it emerges as a moth? That helps it dry its wings properly.
I’m in Kansas and the weather had been very mild for July/August. We had a pretty late summer. I’ll spray the soil periodically to keep in from drying out. My kids are really looking forward to seeing what a white lined sphinx moth looks like. The moths seem to love the moonflowers I have out back so hopefully when I release it, it’ll stay around for a while. Yes, I saw what you told others about having a stick or something for it to climb on once it emerges. It’s all prepped and ready. Thanks a bunch for all your help and advice.
Thanks for the tips. They’ve helped tremendously! It’s definitely a tobacco hornworm. I hope it does emerge, however we’ve been having a vast amount of thunderstorms and rain, only time can tell! Thanks again! I put a pencil in the jar too.
Ashley and Toni,
Thanks for your interest in moths. Good luck!
My little guy hasn’t come out of the dirt yet. Should I be concerned or is this normal considering how weird the weather has been in Kansas?
Yes, insect development is closely tied to temperature. If it has been cool, then it might wait until spring to emerge. There isn’t a really good way to tell what it is going to do, so keep checking.
My daughter found a Great Ash Sphinx caterpillar on a walk. Once I figured out what it was, we tried feeding it lilac and ash. It wasn’t interested in eating but kept wandering back and forth trying to get out. After seeing your blog, I put in some moistened soil and it immediately burrowed in. It was gone in a couple minutes. We live in MN and are getting some warm summer days again (upper 80’s, lower 90’s). Given our location and temps, will it overwinter? Should we keep it outside or inside for now? I’m so glad I found your blog! I’ve been trying to figure out what to do for the little guy, but have only found out what they eat.
Paula,
Isn’t it amazing how the caterpillar digs into the soil like that?
My best guess would be that it is going to overwinter at this point, so you might as well bring it inside. Even though it is warm now, there’s probably not time for it to complete another generation before the first frost. Try to keep it slightly moist and cool, but not freezing through the winter.
I usually put a piece of fabric over the container and hold it on with a rubber band or string.
The hardest part is waiting until spring 🙂
Hi Roberta, its me again, well my moth is already breaking out of it shell all I can see is its legs and theyre moving! Hooray! Howwever, its been 4 weeks since its been in the dirt, and finally I looked and it was sticking out of the dirt! So, now I’m worried its stuck in its cocoon, because all I can see is its legs stick out of the bottom of the cocoon, he hasn’t emerged yet. Do you think he’s stuck? Thanks for your blog,and responses its so helpful!
Well, how is it doing? It is possible for them to get stuck if the pupa case has gotten too dry and hard. Can you give it something to hold onto like a stick? If it seems too dry and it still isn’t out, try misting it very lightly.
About 5 minutes ago my sphinx moth made its way out of the soil. It’s currently hanging out on the sticks drying its wings. It is gorgeous and my kids are so excited. I’m planning to release it tonight near the moon flowers that the other white lined sphinx moths seem to love so much. Thank you for all the great advice. This has been such a wonderful learning experience for myself and my sons.
I just found 4 white lined sphinx Caterpillars at my work in Central PA. I have set up a habitat for them including a living plant that I found them on and some Virginia Creeper. There is 2 inches of rough soil (also from where they we captured). These fellas seem very hungry and extremely regular. How often should I clean their home, replace food plants, and can I expect them to pupate and emerge before too long? I have read that these moths sometimes over-winter under ground before emerging, and I am worried that these late caterpillars are on that schedule.
Toni,
Fabulous! That is very exciting! I appreciate that you took the time to come back and let me know.
Jonathan,
If they are eating, then that’s great. Keep giving them fresh food at least every other day if you can manage it.
How long are they right now (in inches)? If they are good sized, then they will probably quit feeding and start the wandering phase soon. During the wandering phase they will appear restless and crawl around. With soil available, they should dig in and pupate shortly. This late, you are likely correct in thinking they might overwinter as pupae under the soil.
Thanks for getting back to me
3 of them are the green with yellow and orange spots are pretty large, between 3.5 and 4″. The fourth is green with black lines running laterally down the back and is only about 2.5″. They seem to love the Purslane I found them on, but seem uninterested in the Virginia Creeper, Tomato, or Wild Grape. If they do over-winter should I keep their habitat outside. I have a small greenhouse attached to our house, but I am worried they will still reach rather low temperatures over the long winter months.
So here’s whats happening with my moth, after watching it closely for a few days, I noticed less and less movement, the moth doesn’t even look fully developed yet, but the pupa cracked open by itself. It’s just laying still now and barely moving its 3 front legs that are only partially out of the cracked pupa. The back of the moth whe its wings should be I see the colors of a sphinx but I see no wings, only what still looks like a caterpillars body. I’m thinking its getting dehydrated, so I’ve been spritzing it a little with water once a day, but no luck. Should I just wait and see what happens, or attempt to cut open the cocoon?:'( I feel so sad for it. It’s barely moving it legs now.I hope its not dying or partially developed because like I said, I don’t see any wings, aww, poor thing
Ashley,
Sorry to hear you had a difficult experience. Metamorphosis is a complicated process and sometimes things just don’t go right. Cutting it open would likely have injured it even further, so there wasn’t much you could do at that point.
Hope you get the opportunity to try again.
My 6 year old & 4 year old found a big fat White Lined Sphinx Moth this afternoon. I have been researching ever since we put it in a jar as to what to feed it and how to make it a mini home in our giant pickle jar.
So after reading your helpful blog I have a few questions: you said something about 2 broads, so since it is the middle of September does that mean when it pupates that it is going to stay there all winter?
We live in Iowa so what would it most likely eat? I put in the plant it was climbing on and a stick. I am going to put dirt in it tomorrow, I didn’t know it needed dirt until it got dark out.
Thanks!
*A big fat White Lined Sphinx Moth caterpillar*
Dear Meghan,
If your caterpillar is pretty big, then it will probably appreciate having some soil. It is very likely it will burrow in and pupate. If not, check to see if it is eating the plant you gave it. White-lined sphinx caterpillars eat a wide range of plants. If you get desperate, try lettuce.
As for whether it will emerge this Fall, I would suspect it will probably overwinter underground as a pupa at this point in the year.
My son found a white lined sphinx moth caterpillar at church this morning and brought him home in a jar, just wanted to say this site is exactly what I was looking for! We are very excited for him to turn into a big beautiful moth! I hope I can keep him comfortable and alive long enough to see the transformation! Thank you for the info!
I saved about over fifty of them, today, from being stepped on. They were doing their migration thing. One of them, I took home. His name is Julio, a white-lined sphinx. He’s so fat and lazy. Four inches long, by a half-inch thick. He’ll eat anything, including flowers. I am going to give him his dirt, tonight, and hope he can pupate. I wonder if he eats flowers because he’ll be a nectar-drinker, or because he’s a greedy glutton? Thanks for the advice so Julio can morph into a pretty moth and fly away. I may release him back in the desert where I found him.
Good to hear!
my neighbor found a caterpillar at her work so i looked it up and it is sphinx caterpillar. she took it home to her kids hoping it would be a good experience raising it. it buried itself and made a cocoon but her kids dug up the cocoon a few days after making it. she doesn’t want to risk the chance of killing it so she asked me to take care of it. should i bury it back in dirt again? and just keep it in my garage? and is it ok that the cocoon has been handled already? summer is over and its fall now so i know its going to overwinter, i want to make sure i do the right thing.
Thanks for keeping up with the page. But, oh, no. Julio won’t burrow into the soils I give him, no matter what kind, including potting soil, as described above. He’s so cute and fat; I think he’s ready. How do I convince him to burrow and pupate? I found him in the hot Arizona desert. He’s friendly and likes to crawl on me, and lets me handle him, but I’ve tried to leave him alone. No matter what, though, he won’t burrow. Might he want desert dirt (sort of like sand)?
SM Newstead:
If your caterpillar isn’t burrowing, it may just not be ready yet. Did you try giving it some food? It might still be hungry.
Also, I assume you made the soil fairly deep? A couple of inches? It should go into potting soil if it is ready.
Once it has been dug up, I wouldn’t try to bury it again. The caterpillar makes a chamber in the soil that helps protect it and give it room to emerge. However, you do want to keep it moist enough so it develops properly. A compromise might be to lay it on some slightly moist sand and spritz the sand with water every week or so. That would probably create the humidity it needs, but not smother it.
The handling could have caused damage. It just depends on how rough it was. As long as the pupa can still wiggle when touched lightly, it is probably okay.
We just found one of the white lined sphinx caterpillars today. We are in Iowa so it’s getting cooler here although temps have been in the 70’s during the day. Should we expect this one will not emerge until spring? Thanks!
Sarah,
Yes, I would expect it would overwinter at this point, because you would have a chance of frost there soon. Is it still eating?
We found a white lined sphinx caterpillar on the sidewalk of our street a few days ago. We was very plump and so we assumed he was close to pupating. We took him home and put him in a container with potting soil and some leaves. I can’t find the particular plants nearby that he would eat, even near where we found him. My kids and I are very concerned about him. He is very still, never did act interested in burrowing, and is now laying upside down. If we touch him, he will wriggle, so I know he’s not dead. Any suggestions?
Rose,
Sorry it took me a few days to get back to you. I’ve been without Internet this week.
As for not looking good, it might be a couple of things. First of all, the caterpillar could really be sick. Caterpillars do get diseases (fortunately not passed to humans). They also can be parasitized by tiny wasps or flies. Or, it could be that it is beginning to turn into a pupa. The caterpillar will start to swell and stiffen when it is getting ready to pupate. It will form what is called a prepupa.
If you stop back, please let me know what is happening.
I am so glad I stumbled upon this blog post. A few weeks ago my son and husband found a white lined sphinx moth caterpillar crawling across the driveway at my dad’s house. They brought it home to try to find out what it was and possibly see if we could watch it change. We managed to figure out what it was (it was a little difficult because it was black instead of green) and that it needed soil to pupate. I also read that one of the plants that it could possibly eat was elm, so I grabbed some volunteer elm trees out of my flower bed and put them in a large clear plastic container with some potting soil. It crawled around the container and on the small trees all morning after putting it in and by the afternoon it started digging under some of the leaves. It was fascinating to watch. I’m sad my son who found it missed seeing it do its thing while he was at school. After reading through all the comments, I know to expect it to stay there until spring. Do you happen to have an idea of when to expect it to emerge? (March, April, May?) We live in Southwest Nebraska. I was hoping to take it to my son’s kindergarten class and my daughter’s preschool class so they could see it as it comes out. We also have a mystery caterpillar we are raising. I found it eating my green onions, so I put it, some soil and the green onion in another clear container. The other day I noticed it was gone after it had dug a tunnel around the edge of the container (I also expect it to overwinter before coming out as a moth). I have a picture of it on my phone right after it had nibbled the top off a green onion if you would be interested in helping me to identify it. Both containers have a slight moisture build up inside, but I don’t think they are too wet. I have the lids on with holes cut in the top. Thanks for any help you can offer.
Oh my, you have a lot of exciting caterpillar goings on.
As for the sphinx moth, I’m afraid it will be hard to predict accurately because when the moth will emerge will depend on a lot of local factors, the most important on being temperature. One way to control it a bit would be to keep it cool for a few months and then warm it up. Hopefully it will emerge shortly after the raise in temperature. I’m sorry I can’t give you more specific numbers.
As for the onion caterpillar, it might very well be a cabbage looper: http://blog.growingwithscience.com/2008/10/bug-of-the-week-cabbage-looper/ We get them in our green onions. If that doesn’t look right, try googling “leek moth caterpillar.” If that doesn’t look right either, then either load it to a photo sharing site like Flickr or Photobucket and send me a link, or feel free to share it on the Growing With Science FaceBook page. I would be happy to take a look.
I just shared a picture on your facebook page. I will go put the caterpillars in the garage until February or March so they don’t freeze. Hopefully I don’t forget about them! 🙂
Got it! Very nice.
Yes, forgetting is easy enough.
Thanks for this wealth of information on the White-lined sphinx moth (Hyles lineata). I found one last Friday on a Calylophus berlandieri plant (Square-bud Primrose), which is in a 6″ pot that I was going to transplant into my native plant garden (which already has a couple Calylophus plants). I held off until I could identify the caterpillar, to protect it from birds and an incoming storm. The caterpillar was about an inch long last Friday; by today it is 2 in. long and has doubled its girth. It is chewing on the primrose plant and should have enough food (I also have Cedar elm, which they feed on). It sounds like the caterpillar may find enough soil in the pot it’s in to burrow it’s way to the pupa stage, but I am wondering what would be best for the plant/pupa if it overwinters. The pot is in a protected area with light and air (on our back deck), but I am wondering if plant & caterpillar might be better off transplanted to a slightly larger pot so they have more room. Any thoughts?