these monarch caterpillars failed to pupate (turn into a chrysalis)...
why? what happened to these caterpillars?

# jump to feedback / questions / comments below

see also:
raising Monarch caterpillars in Santa Barbara
image gallery of milkweed, Monarch caterpillars, butterflies, etc
Monarch caterpillars eat butternut squash
tachinid flies are killing my monarch caterpillars!

2020 update - indoor Monarch caterpillar / butterfly enclosures
If you are interested in raising your Monarch caterpillars inside, both to protect them and see them turn into chrysalises and then butterflies, several readers have recommended checking Amazon for their enclosures for raising Monarch caterpillars to butterflies. It looks like Amazon has a good selection of inexpensive, portable, and easily stored caterpillar/butterfly enclosures. Something worth considering...

Floral tubes - Amazon also has this 10 pack of floral tubes for preventing your milkweed cuttings from wilting. Floral tubes are the plastic water-filled tubes that you've probably seen on the end of long-stem roses.

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As part of my study on tachinid flies killing Monarch caterpillars, I attempted to "raise" several Monarch caterpillars from eggs. The first egg I raised was a success. The caterpillar hatched, grew up into a big fat healthy caterpillar, then pupated and turned into an elegant light green chrysalis, and then later emerged transformed as a healthy happy Monarch butterfly. I expected the same success with two subsequent eggs I collected just after observing a butterfly lay them, but the results were quite different. For egg #2 and egg #3, the caterpillars hatched as expected. The two caterpillars seemed fine and grew to full-size, and I expected them to turn into chrysalises just like the first caterpillar. But instead, both failed to successfully turn into chrysalises. The caterpillar from egg #2 started to split its skin, but then stopped, and eventually died. In addition, it wasn't able to hang onto its silk button. The caterpillar from egg #3 sort of turned into a partial chrysalis, but was hanging by its elongated stretched skin, and wasn't a full chrysalis. It too then died. I have not idea what happened to these two caterpillars. It had nothing to do with Tachinid flies, as no Tachinid maggots ever emerged. Instead the to partial chrysalises just darkened over time and then began to mold.

monarch caterpiller fails to turn into a chrysalis  deformed monarch chrysalis hanging by stretched caterpiller skin

So if anyone know what could explain the two pictures above, please comment and let me know. Why is the caterpillar from egg two not hanging directly from his silk button, and why did he start to split his skin and then stop. And why is the chrysalis from egg #3 caterpillar deformed, and hanging from the elongated caterpillar skin. I've never seen anything like this before.

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Comments / Questions / Feedback:

Comment by Mary on Wednesday, July 27, 2016
This is very interesting. Has me stumped too. I just thought it is interesting #3 still has its caterpillar prolegs even after becoming a pupa. Or rather the abdomen still looks like the caterpillar's.
I wonder if anyone else was able to help you figure out what happened. Doesn't look quite like the OE disease monarchs get? Could the food you gave them have been exposed to pesticides? (nursery bought plants or harvested from a park, business or wherever else they might use chemicals on their lawn and garden?)) How was the humidity and temperature? Did they have trouble spinning their silk pads? I notice if they don't get a decent anchor or have to redo it, sometimes the caterpillar might not make it in time to properly J before having to split. Another thing that can do harm is if they get an injury on their rear end.
As far as #2. The caterpillar probably stopped because it was too weak to achieve the molt. Another culprit could be the dreaded NPV virus. This would cause them to turn into liquid goo.

Reply by Steve (Cranial Borborygmus)
Hi Mary, Thanks for your comment and thoughts. My backyard is pesticide free, and all of my milkweed was grown from seed, so I don't think it has anything to do with pesticides. It might be a virus like you've suggested, but if so, it was a one-time thing. I've never seen anything like this before, and never since. I let most of the caterpillars grow up on the milkweed, and then they disappear and turn into chrysalises somewhere (I hope). Sometimes I find chrysalises (or empty chrysalises), but often I don't. So maybe it's happening in "the wild" of my backyard, but I'm not aware of it. I still lose a lot of caterpillars and chrysalises to the Tachinid fly, but again, I've never seen something like this again. If anyone else has any ideas, please let me know. Thanks again for your comment!

Comment by Monique on Sunday, August 28, 2016
Caterpillars are easily stressed if it looks like the food supply is low or if they "run out" often and they will begin to pupate prematurely (before they really should - sometimes as early as 4th instars). #3 may have died halfway into pupation. I have seen some remnants of prolegs on chrysalis and believe it is due to a hasty pupation (less than 18 hours in the J mode). I believe #2 probably also pupated before full maturity as well. It is also important to have a proper anchor so the contractions can pull the skin off the body quickly with exhausting the caterpillar. Can't really see what is happening on egg #2 where it is anchored. A sign of being too weak to pupate is being too weak to form a proper silk pad to anchor to. I think the caterpillar needs copious amounts of food with no interruptions for as long as possible as a 5th instar before pupating to maximize success.

Reply by Steve (Cranial Borborygmus)
Hi Monique, As far as I remember, the caterpillars had enough fresh milkweed leaves, but maybe the issue was still some kind of stress as you suggest, and they simply began to pupate before they were ready. I'm just surprised I've never seen this before (and I did have some caterpillars run out of milkweed and I then fed them butternut squash, and they lived and turned into butterflies), and I've never seen it since. It also happened to two in a row, not just one. Anyway, your explanation could be it, at least that it was some form of stress, but not necessarily running out of food. Thanks for your comment and insight!

Comment by Monique on Wednesday, August 31, 2016
Depending on how the milkweed is presented they may not migrate to the fresh leaves and cling to their old stripped down stems (check the amount they are eating from the leaves). Excessive heat or dryness will make them pupate prematurely and usually unsuccessfully. Make sure their environment is humid >50% Relative Humidity, and stays below 81F and does not fluctuate more than 15F (glass enclosures like an aquarium can get very much hotter than the surrounding air even if not in direct sunlight). Also pulling cats from the "wild" at too late a stage and bringing them into captivity will make them pupate. They just want to get out of the captive environment and will not eat anything. They have a healthy flight instinct (fight or flight) and if they are scared they can be in flight mode for hours until they are exhausted and pupate. Stress really takes a toll on them. Maybe #2 attempted to pupate in direct sunlight. Make sure they are not pupating in direct sunlight and relative humidity is extra high for safety.

Reply by Steve (Cranial Borborygmus)
Hi Monique, Thanks for your additional comment and great information and advice. In my case, these two caterpillars were raised from eggs I found outside. Their little shelters were outside in the shade with ample airflow, and they had plenty of fresh milkweed. I would add new leaves and they finished the old leaves, and they would quickly move over and start eating the new leaves. I don't remember what the weather was like, since it was last summer. It might have been hot and/or dry. I just can't remember. In any event, your information is great advice for anyone raising caterpillars in captivity. Thank you!

Comment by Pam on Tuesday, September 20, 2016
I don't have any ideas regarding your issue but this year I have had the same problem. I have had several cats go into J shape and only form 1/4" chrysalis. Some were hatched from eggs and others I found as 1st or 2nd instars outside. Raised them indoors in a spare bedroom. None ever ran out of leaves and I don't touch them. I'd like to know what's going on.

Reply by Steve (Cranial Borborygmus)
Hi Pam, I'm sorry to hear that you had the same or similar problem. Very strange. Thanks for sharing your experience.

Comment by Linda McCulloch on Saturday, September 24, 2016
Hi all, I was extremely happy this month to have a lot more monarchs, and therefore many more cats on my milkweed. Like many of you, my yard is pesticide-free, and all the milkweed is self-seeding and has been for several years. I have plenty of milkweed so no worries about the cats running out of food. So at least 9 of the cats got really big, fat, healthy-looking etc. This week they began working their ways off of the milkweed and over to other plants to pupate. (They seem to really like to pupate on our large clumps of garlic chives.)
But! Yesterday and then today I saw two of the cats, hanging from the chive stems, just straight down, with their silk hanging loose. They never formed the J shape, or if they did I did not see it. Now they are sort of shriveled looking and obviously dead.
I have not seen any Tachinid fly maggots (yet). And now that I have decided to look out here on the Internet and have seen some similar problems, I am concerned. We do live in Georgia, which is in an extreme drought situation and it's been hideously hot. Could the cats have gotten dehydrated somehow? I read on another site that some folks think it's a good idea to spray-mist them as they grow.
Any additional thoughts welcome. If you need me to upload a picture let me know. I haven't shot any, but I could do that if it would help.

Reply by Steve (Cranial Borborygmus)
Hi Linda, I'm not sure what you mean when you say the dead caterpillars were just hanging there "with their silk hanging loose". But if you mean you saw thin white silk threads dangling from the dead caterpillar, then that means the cat was killed by the Tachinid fly maggot, and the maggot has already emerged and then dropped to the ground via the silk thread. You probably won't find the maggot because it will wiggle away and hide, and then turn into a hard little reddish-brown "seed". A few days later, the "seed" will hatch and the fly will emerge. I have a different post on this website about the Tachinid fly, and have pictures on it. It's a problem I haven't been able to solve yet, but fortunately at least a few of our caterpillars somehow avoid the flies and turn into butterflies, but with the others it always hurts to lose them.

Comment by Linda McCulloch on Sunday, September 25, 2016
Hi Steve, Thank you so much for your answer, I am now fairly sure that you are correct about the Tachinid fly maggots. Yuck. But your description is very accurate, and the fact that the caterpillars look shriveled and kind of empty would make sense, if the maggot ate them from the inside out. (Double yuck.) I will keep looking for healthy chrysalises of the remaining cats because we had a lot more this year. Fingers crossed.

Comment by Ola on Friday, September 30, 2016
Found this thread because this just now happened to one of mine. Looked healthy, j formed properly, antennae went limp and skin started to split and then stopped. Raised this batch from eggs and cleaned the leaves (though no pesticides used outside) before giving them to caterpillars. First time this has happened to me. Very distressing. Am in So.Cal.

Reply by Steve (Cranial Borborygmus)
Hi Ola, Thanks for your comment, and for letting me know this happened to you too. I think it must be fairly uncommon since I didn't find anything about it when I searched online after it happened to me, but thanks to your comment and also Pam above, I now know I'm not the only one this has ever happened to.

Comment by Debbie on Monday, October 03, 2016
I live in Southern California and this is my first year raising Monarchs. Just recently I had one cat partially pupate, and one hung that it's skin began to shrink from the tail. I'm glad to see other posts with the same experience. I have had successes and losses, losses outnumber successes, unfortunately. I do raise them inside and release them when they are ready. It is October and there seems to be no slowing down of Monarchs laying eggs in my small patch of milkweed! I currently have eight entering into their J stages and have recently released 7. Knowing that only less than 1 in 10 make it into the butterfly stage encourages me for my small hatchery, and very happy for the successes I have.

Comment by Tiffany on Monday, October 10, 2016
This has happened to me with three separate chrysalises this year! It's so strange indeed. Earlier this summer, one of them formed only half of its chrysalis. After a couple weeks of watching and wondering, it was obvious that it was long gone. The next one only formed half, and I figured it would be the same untimely end, but the next day it finished forming the chrysalis! I was shocked! It has only been 5 days since then, so I'm anxious to see if a butterfly will really emerge from that one. And the third just happened yesterday. It looked big and healthy and hung in a J yesterday morning and by evening had only formed a small cap of chrysalis on the top of its head. It's been over 24 hours now and no changes, except it's no longer in a J and is straight and limp. I'm nervous to consider it a goner though since the second one seemed to finish with a little more time. It's just so weird and every failure makes me a little sad, even though we've had over a dozen successes this summer! After reading these posts I'm guessing that they got stressed about the food availability because they were indoors in their own containers but their leaves were on the crunchy side (although the third one did have a butterfly emerge in the same container a couple of weeks ago). It's also pretty dry here in Utah. I'm sure it's too late in the season to find more eggs, but I'm hopeful that this won't happen next year!

Reply by Steve (Cranial Borborygmus)
Hi Tiffany, Thanks for sharing your experience. Maybe this is more common than I thought. It's very interesting that it happened with your caterpillars three times this year. It's especially interesting that the second caterpillar stopped pupating half way through, but then was able to finish pupating the next day. I had no idea that was even possible. I hope you will update us on whether or not that chrysalis turns into a butterfly. This is very strange indeed!

Comment by Sarah on Tuesday, October 11, 2016
I have lots of milkweed around my complex and the yard guys hack the plant so I take caterpillars and sometime cut the chrysalis branch off to help them. I let them roam on my porch with milkweed and other plants available. They can easily crawl to a plethora of moll weed if they want but they stay. They need space. They don't like to be crowded. I supply fresh milkweed flowers on top of having a milkweed plant. This has happened with a few of mine too. I live in Az but keep them in natural environment. Outside. I mist water on the plant sometimes to keep them hydrated and cool too.

Comment by manda on Sunday, November 13, 2016
I am devastated. I had about 10 caterpillars, extremely healthy and the plant was still full of leaves about a week ago. They looked like they were full size, but now I can't find any pupae hanging in the butterfly weed or nearby plants. Do the caterpillars move away.. and if so, why? What do you think happened. I don't even see any dead pupae hanging... basically no trace of them.

Reply by Steve (Cranial Borborygmus)
Hi Manda, Don't be devastated. I think your caterpillars are probably just fine. They won't hang and form a chrysalis when they're in the milkweed. Instead they will wander off somewhere else to form a chrysalis. I think they can go 50 feet to 200 feet or more. All of our outdoor caterpillars get big and then "disappear". We've been luck enough to find a few chrysalises in trees, in bushes, and on walls (up to 50 feet away), and sometimes don't find the chrysalis until later after it's hatched and empty. The only way to see them form a chrysalis for sure is to "trap" them and keep them in a container (make sure they have enough leaves to eat until they're ready to pupate). We just let our outdoor caterpillars do their thing instead, which means most of them "disappear" but we're pretty sure most turn into butterflies. Take another long look around your yard, and you might find a chrysalis. Good luck!

Comment by Alex on Sunday, December 11, 2016
Hello, One of my monarch caterpillars has fallen off of its leaf it was attached to. The branch was accidentally severed which wilted the leaf and when I was trying to move it to a safe place it detached and has not moved - it looks asleep, no movement. I have no experience with butterflies. Help pls, what can I do?

Reply by Steve (Cranial Borborygmus)
Hi Alex, When a Monarch caterpillar is disturbed (i.e. if they fall, or if you pick them up) I think they typically will curl up "play dead" for a while. Hopefully, that's all that was happening with your caterpillar, and after a while he should uncurl and crawl away. Good luck!

Comment by Eileen on Monday, January 23, 2017
I've had a similar problem with half-formed or less chrysalises in my last two cats. Both were brought in from the milkweed outside. The weather had been quite cold and windy here in FL, so we thought we were saving them. Both ate well and the second one was placed on a plant in a netted house. Yesterday I watered the plant in the cage and my cat fell down onto the wet ground. I tried to help it get back on a leaf and saw it crawl up a stem and stay there. This morning it hung straight down on that stem and its head had a small amount of chrysalis. It's obviously dead. Is handling the problem?

Reply by Steve (Cranial Borborygmus)
Hi Eileen, Thanks for your comment. I'm sorry to hear that the partial-pupation problem happened to two of your caterpillars. I don't know what causes it, but from the comments here, several people have seen it happen. A few theories have been posted here, but I don't know what actually causes it or if it could be multiple factors. I just know that it isn't very common, and I'm guessing that your next batch of caterpillars will do better. Good luck!

Comment by Joan Moore on Monday, May 29, 2017
Seems that I have had all of the same problems as the ones described above. It was ok trying to raise Monarchs in spring, but now in Ft. Lauderdale the temp has risen to 100 degrees with high humidity. One of my chrysalis fell from a leaf and the top popped off and an owey gooey yellow spilled out of the top. The one Monarch that was born in early May flies around and is constantly laying eggs. When they are not put into a cages the lizards eat them. Don't know how to stop the process and wait until it gets cooler in the fall. I get so upset when they get sick, just don't know what to do.

Reply by Steve (Cranial Borborygmus)
Hi Joan, Have you ever actually seen a lizard eat one of your caterpillars? We have a lot of "blue-belly" lizards around, especially this year, and I've sometimes wondered if they eat caterpillars, but I've never actually seen it happen. I like watching our lizards... I just hope they aren't eating our Monarch caterpillars!
I understand how depressing it can be to see the caterpillars and chrysalises not make it... but at least sometimes they do! I'm not sure what to recommend, other than it will be better in the fall. Good luck!

Comment by Joan Moore on Sunday, June 10, 2017
Thanks for getting back to me. I have never actually seen a lizard eat a caterpillar, but when I first started out with milkweed I moved my plant with at least 15 caterpillars from a very sunny place to a more shady area under a nice shrub. Also, I added a few other milkweed plants so they wouldn't run out of food. The pots were on the ground. At one point I walked over and saw two lizards fighting among the milkweed plants, although one was a curly tailed pot belly from the Bahamas, and very aggressive, I didn't think much of it until the next day every single caterpillar was gone from the tiniest to the full grown one a total of about 15 caterpillars. I was horrified and moved all of the plants out of the area. That was when I ordered the mesh cages. Only one Monarch caterpillar has survived out of 30 on its own. Now that I have the cage there are many chrysalis on the roof and I can't wait to see them hatch. The caterpillars also are now dining on cool cucumber chunks when they get big enough. Sometimes they lay across the cucumber, it is very cute. Happy Monarchs.

Comment by Brooke Brown on Saturday, July 01, 2017
I've raised 80 or so over the last 2 years. I have had this happen sporadically. It won't be ALL of them, but it generally won't just happen to one of them. I asked an etymologist, he thought that maybe they were dehydrated. I raise them inside, in the air conditioning (set at 78), but I spritz them with water twice a day. But I don't know if that was actually the trouble. :(

Comment by Cassie Graham on Monday, July 10, 2017
We've had the same experience with cats unable to continue the chrysalis process here in Southern Florida. Based on the above comments our problem could be the direct sunlight. We'll test that by making shade available! But, I tell you, it was absolutely HEARTBREAKING to see many, many fat caterpillars start the chrysalis and then be unable to complete it!

Comment by AD on Sunday, July 16, 2017
I've successfully hatched/raised 7 monarchs this season from eggs or various instars (all brought in from outside), with 3 more in a chrysalis, 2 getting ready to hang and another that sounds like other comments here. It lost its anchor, is hanging by a single thread and has failed to get its skin all the way off once it started to pupate :( it was squirming and trying its darndest to successfully pupate but now it's still. The top and bottom split but the middle didn't. It's a chrysalis with a corset and the skin on the top/bottom is still all on one side of the corseted chrysalis. I don't think this one is gonna make it. :( Never had this happen before.
This poor guy is one of 3 in the same space. The two other cats can't seem to leave each other alone, they keep getting in each other's space interrupting the process to form their anchors (they have a 13in by 13in space so it's big enough and no matter the size of the space if there's more than 1 they always seem to encroach on each other). I've never had problems with 3 in that space before, I usually only have 1 or 2 in it though. I'm a little nervous that the cats are sabotaging each other.

Comment by Marnie on Tuesday, July 25, 2017
I've read all the info on monarch diseases and none match what I've incountered. In years past I've had catapillars "get sick". Their droppings become a green liquid. They than stop acting normal and die in a couple days. Some try to hang before they are ready. I have found that any catapillar that are exposed will not survive. If they are in a crystals form they seem to be ok. If exposed just befor they turn into a crysislis they will be deformed, wings won't develop or missing toes so they can't grab to hang while drying. I've tried bleaching cages, not putting them in cages until they are big and fat. I've raise catapillars for several years and still don't know what it is or how to prevent it. This year, I had three small catapillars I brought in just before they were to hatch and had one catapillars that was bigger. The bigger one was smaller than the group it was with so I didn't cage it like the others that were ready to crystallize. The one older catapillar failed to complete the crysilas process. Half way tru, it seemed like the outer skin wouldn't split and it strangled. It left a black puddle on the bottom of the cage defore it died. The three small catapillars became sick the same day. I found one that drowned In the vase water and the other two just stopped eating, tried to hang and died. They were only 10 days old after hatching and not very big.
Has anyone else incountered "sick catapillars"?

Reply by Steve (Cranial Borborygmus)
Hi Marnie, I've never seen the things you are describing. From what I've read, "OE" is a pretty big issue, but I've never experienced it nor do I know much about it. The only real issue I see where I am in California is the Tachinid fly, which even by itself, can be a huge problem. As for the pictures of failed pupation that I posted, I really only saw the problems once and haven't seen it since, so at least for me, it's rare. Anyway, I'm not really sure what you're dealing with, but it sure sounds frustrating! Thanks for commenting, and good luck!

Comment by Marnie on Wednesday, July 26, 2017
Thank you for responding. I did some more research after I sent my post. I search "monarch caterpillar with green diarrhea" and found a very possible cause to my dying caterpillars. I mentioned this has happened for several years. I am sad to report I very well have been unknowingly killing my caterpillar. I use frontline on my cats and dogs. I wash my hands after treating them and before I handle my caterpillars but possible not enough. I frontlined my pets the day before I noticed a problem with my caterpillars. It would make sense that this is the cause. Please share with other caterpillar caregivers. I will continue to care for caterpillars in the future but will wear plastic gloves when washing milkweed and handling the caterpillars and keep my nosey cats away from them. I'll let u know if this continues to happen. Again, thank you for your quick response and please share so this doesn't happen to others.

Reply by Steve (Cranial Borborygmus)
Hi Marnie, Thanks for your follow-up. I'm not sure if I would have ever guessed that it might be the anti-flea medication that you put on your pets, but that makes sense. It probably only takes a trace amount! We used to use Advantage on our cat, so I'm familiar with it. Our cat passed away a few years ago (she was 19 years old, rest in peace), so we don't have Advantage around anymore, but it makes sense to be super careful if you have pets and use Frontline, Advantage, or any other anti-flea pet medication.  Thanks for sharing this information!

Comment by Mary Beth S. on Wednesday, July 26, 2017
Hello, I live in Iowa and have unsuccessfully tried to raise 4 caterpillars - each one has succumbed to the same problem as your Egg #2 photo. They have seemed healthy and active, right up until they attempted to pupate. The cap formed right behind the head, but the rest of the caterpillar withered away and leaked green fluid. So incredibly heartbreaking. Three of the caterpillars I found as first instar larva, and they all molted at the same time. We were so excited for them to pupate. I believe I was giving them adequate food, and all my milkweed have been produced from seed. All of my caterpillars have only ever been found on A. tuberosa - I never find / feed them common milkweed. Could this be a problem for them?

Reply by Steve (Cranial Borborygmus)
Hi Mary Beth, I'm not an expert at all, but I don't think it is related to the type of milkweed they eat. There are valid arguments over what type of milkweed to grow depending on where you are, but I don't think the type of milkweed could cause this problem. Some readers here have suggested possible causes, including Marnie who just commented that something similar happened to her, and she thinks it might have been because she put put Frontline anti-flea medication on her pets the day before she handled her caterpillars. It probably can be caused by a variety of things, but fortunately is still seems to be fairly uncommon. I wish you better luck on your next caterpillars! Thanks for commenting.

Comment by Mary Beth S. on Thursday, July 27, 2017
Thank you for the reply! I think I will keep trying and hope for the best. We have so much milkweed, some monarchs, and a LOT of predatory wasps. I have to believe some day it will be successful. Our home is relatively chemical free however we live in an area surrounded by corn / soybean fields and crop duster planes are frequently spraying the fields around us. I wonder if pesticide drift, even at very low levels, could be the culprit?

Comment by vesta on Monday, August 21, 2017
I don't know but I don't think it is as uncommon as previously thought, or maybe it is becoming more common. After having two perfectly fine batches of cats to butterflies, the third batch of 10 all died.....They ate voraciously, got quite big, molted larger and larger and seemed perfectly normal right up to forming silk buttons and forming the J, but then, one by one, as they started to form the pupae they just stopped unzipping about 1/8 to 1/4 of the way. There was some writhing and obvious distress but they were not able to continue, and passed away. Something is happening. I'm in Connecticut but this sounds like what is happening in Calif, and Arizona as well. ???????

Reply by Steve (Cranial Borborygmus)
Hi Vesta, Thank you for your comment. Just to clarify, did this happen to all 10 caterpillars? Did they ALL only partially "unzip" and then die? If it happened to all 10 out of 10 caterpillars, that is both a lot of caterpillars and a very high (100%) rate of the problem. It would also be something I've never heard of or read about until now. Thanks for sharing this information, though it must have been very disheartening to have happen.
If you have any more caterpillars, I'll be interested to hear how they do, and whether or not this is a one time event.

Comment by Eva on Wednesday, August 23, 2017
Hi, I'm in Memphis, TN. Just wanted to mention that something similar happened to me as well. Found this post searching for answers. I raised my caterpillar from an egg, and it seemed healthy and happy, but then it pupated as what appeared to be a 4th instar. I was concerned that it had pupated too early, and rightfully so, because I believe this played a role in its failure to form a chrysalis. I had it in mesh cage with another 5 instar cat and another that had already formed its chrysalis. Both active cats were on their own cuttings. However, a thunderstorm rolled through and the cage had a bit of rain blow into it (the cage was sitting on a porch). I promptly cleaned and dried the cage. However, the current (successful) chrysalis was forming at the same time as the one that failed and rain didn't seem to affect its process- although that cat was a small 5 instar.
Not sure why it pupated so early. It was on its own milkweed cutting, and had a good amount left. However, it had spent most of its caterpillar life indoors in a plastic enclosure and was then moved outside when it got big enough (and wouldn't be able to escape its new cage). It had probably been outside about 1 day before it pupated. I wonder if it could be due to a sudden humidity/heat change? Eva

Comment by Sheila on Tuesday, September 05, 2017
I had the issue with several cats! They were monster sized and definitely not transitioning too soon. I was thinking maybe they were so much larger due to they are probably the last batch that would be flying to Mexico. I cannot find any obvious issue. they were all raised in separate containers as well. I did not share any materials between them and my milkweed is from my own garden. No pesticides! They are spraying for Gypsy Moth Caterpillars many miles from here. I was just pondering if something carried on the wind that may also affect these ones.

Comment by Monique on Wednesday, September 06, 2017
I had an incident this year which I believe reveals the cause of egg#2. I posted last year too. I keep my caterpillars in a breezeway which can unfortunately experience large temperature swings. The day before I had a couple Jed caterpillars that went south because it was too cold (68F or lower). They look like their prolegs did not "dissolve" and their wings do not attach to their mid section in the chrysalis and slides off (melting). With a space heater and boosted the temperature for the remaining Js. The temperature control was not trustworthy and the room got up to 84F. I had 6 Js in one full mesh cage form like egg#2 and another isolated J in a mesh cage in the same room do the same thing as egg#2 in your picture. I then purchased a temperature probe to trend the temperature throughout the day and to have better control. Another Jed cat was fine before I left for work at 72F at 7:30 am. It actually dripped out (bled out) when it tried to pupate when I found it after coming home from work. I checked the temperature trend and amazingly the room temp had reached 83F (without heating). At 1pm it exceeded 80F and remained 83F from 4 to 5 pm. Only when the temperatures have been 83F or 84F (the only 2 data points that I have) has the problem of egg#2 occurred. A caterpillar can normally deal with this temperature but when it is Jed up and dissolving its exoskeleton (chitin) I believe the mechanism to deal with excess heat are not available. I believe a safe temperature zone is 75F to 78F. Also when it is dissolving its exoskeleton (J'ed up) and recently pupated, I believe it does not not have the mechanisms to protect itself against average UV radiation in sunlight. My caterpillars are fed home grown tuberosa milkweed with no pesticides on the property. The pupating deformities are not related to milkweed or other diseases but merely temperature control at a critical point in their development.
Egg#3 clearly died in the pupating process. I had never seen that happen until this year, where the skin remained halfway down in the pupating process and the caterpillar just quit the contractions to push the skin off. It also had other deformities in the exposed regions. It seemed like it exhausted itself in the pupating process. In the egg#3 pic there seems to be a big difference in the extremities of the caterpillar indicating a potential large temperature gradient between the upper body and the prolegs. The prolegs never "dissolved" back into the "soup". Temperature probably played a role here as well.
I noticed that temperature is not being mentioned when folks see this problem. You can buy a cheap monitor that logs high and low temp for each day. If you could include the high temp during the Jperiod, that would be great info for us all. Thanks!
PS. A quick note about "ample air flow". I think it is critical to only have convection air flow. Air the flows with very low velocity in a vertical direction (hot air rises and cool air falls) as well as allowing carbon dioxide to flow down and out of the enclosure (mesh). When the chrysalis hardens, oxygen is a component of this process. Even a ceiling fan at low speed could have too much of drying effect (boundary layer) not only on chrysalis moisture but could hasten the hardening process (extra oxygen in boundary layer) before the pupating process completes. Air conditioned air could be especially dry (dyer than ever seen in nature) can cause problems. I am also trending carbon dioxide levels in the breezeway and I am surprised how quickly they go up when I am present in the room. So I have a whole new appreciation for air flow.

Comment by Eve on Thursday, September 07, 2017
I've been having very similar issues. I have 7 cats and 3 formed nice looking chrysalis but the 4th stopped forming and looks just like your "egg 2." I have a 5th that is struggling and I fear it's going to end up like egg 2 as well. I've had success raising caterpillars without any issues before but now this has happened to two caterpillars in the same group. They've had plenty of food and I've been fairly meticulous about keeping their home clean so I'm not sure what the issue has been. After reading some of these comments it may just be a natural thing that happens. Maybe it's OE or something else. like you said, I don't think Tachinid flies are the issue don't think there are Tachinid flies in my area so I don't think those are the culprits.

Comment by Patti on Friday, September 08, 2017
Hi. I'm in western Pennsylvania and brought in 10 caterpillars. I have 5 that are in successful chrysalis but 2 had the same thing happen as you describe above. One other did the upside down v thing which is symptomatic of NPV. I've rationalized that these other 2 were exposed and unable to complete a full pupation. This is my first year at attempting this so I don't have years of experience to draw from. I have one continuing to eat and one other in j so I shall see how the remaining ones do.

Comment by Karen Essig on Saturday, September 09, 2017
I just wanted to share some good news for others who have had a chrysalis that didn't fully form. We watched a caterpillar turning into chrysalis and it shed it's skin just fine until it got half way up and it was wriggling and couldn't finish the process. The chrysalis was green and looked just like the others but it's body was half way out of the chrysalis. I was going to throw it away because I thought it was dead. My husband told me to leave it and give it a chance because the chrysalis was green and had the gold on it. Yesterday it eclosed. It looked just fine. The back half of the body was skinnier but other than that it was able to fly. I just want others to know that they can live when they don't fully develop. I've attached pictures of the chrysalis and butterfly below.
PS. I wanted to share this because I saw a picture that looked just like mine and the lady told me she destroyed it. I want to help educate people. This is my first year and I am learning so much from websites like yours. Thanks, Karen

Reply by Steve (Cranial Borborygmus)
Hi Karen, Thank you for sharing your experience and pictures! What a fantastic outcome! By the way, thanks for teaching me a new word in your comment, "eclosed". I wasn't sure if it was a typo, so I Googled it and learned that eclose means "(of an insect) emerge as an adult from the pupa or as a larva from the egg." Thanks again for commenting!

Comment by Anita on Monday, September 18, 2017
I am in southeastern Wisconsin, have one from egg in "J" only forming a blaze on its head and seeming to stretch from its button. I had this happen to one before this year. Have released 40+ and began tagging. Have tagged 9 so far, found my first one dead in the grass yesterday. That was so disappointing. No obvious signs of any damage. Will save if possible for wings I guess. The township does drive by at night spraying for mosquitoes. I saw one fluttering around a maple by the road a couple hours before finding this one. Assuming it's the same one but impossible to know, it wasn't too far away in the grass.
I use castille soap if anything, the aphids are horrid, corn field across road.
Have accidentally fed poison milkweed, lost about 5 immediately, but afraid even the survivors eventually succumbed.
I wash it, assuming systemic herbicides.
Will keep you posted about this cat. Very sad, only one to go. One other went in chrysalis in same cage yesterday.
Thank you for this feed! 1st year actually rearing from eggs. Have done my best to isolate if I brought any in. I euthanized the 1st.

Comment by Anita on Monday, September 18, 2017
Followup - the cat I wrote about earlier only developing a "blaze" of chrysalis has fully gone into chrysalis. Such a relief! 2nd to last one. I will miss these guys as much work as they came to be. I hope for successful eclosures for all, 5 getting ready to come out today.

Reply by Steve (Cranial Borborygmus)
Hi Anita, Thanks for the follow-up... that is great news! Good luck!

Comment by Lisa on Tuesday, October 17, 2017
This is my first experience with Monarch eggs, larvae and cats! It is so addicting and satisfying.
I have two chrysalis, probably 7 cat 3's, one cat 4 or 5, and just recently, found 6-7 "tiny" larvae on the milkweed plant that I pit on my balcony to protect any more, if any eggs. It's already October 17th. I had a big cat 5 caterpillar that formed the "j" on the net where the other large caterpillars are, in an enclosed netted place on the other balcony. It was not there this morning. We did have a cold night, here in California, but today is warm- 78-80 degrees. I noticed it fell between the potted milkweed plant and the net. I was able to carefully cut the net and put it into a piece of soft net- (plant cover). It quickly attached itself, again, but only half way. I brought it inside to my "indoor" housing for the larvae. It wiggled and wiggled, upside down. After two hours, it hadn't changed, although it was fat and definitely "ready" to form the chrysalis. All the wiggling did not help change my poor little caterpillar to the next stage. So, I made a sort of "hammock" above the outside netted butterfly enclosure. That way, if he/she survives, can reach up and hopefully attach. I just don't know whether to bring in the outside enclosure, in case it gets cold again. I think they are used to mildly cold nights. If this Monarch cat fails to attach or form a chrysalis, I will wonder what the problem was. I will not give up! I live in Marin County, CA. We did have a lot of smoke from the Santa Rosa/Napa fires recently. I live approximately 40-60 miles away.

Reply by Steve (Cranial Borborygmus)
Hi Lisa, Thanks for your comment. Yes, "raising" Monarch caterpillars and butterflies can be very fun, though it can be tough when they don't all make it, which happens. I think you are doing all you can do for your caterpillars. I don't have any specific advice. I think they can handle the mild California fall temperatures just fine, so I don't think it is that. Some of them just don't make it all the way. Keep up the good work, and good luck!

Comment by tracie on Friday, October 27, 2017
This is only my second attempt at raising monarchs. A couple of months ago I had 24 cats and lost most of them to the tachanid fly. I had three monarchs hatch. Two weeks later I watched a monarch lay over 150 eggs on my milkweed plants. I collected every egg and raised them inside, until they were first or second instar. I got a greenhouse and a lot more milk weed and continued monitoring them. As of yesterday I have 30 chrysalis, formed...but today I had 10 more that did not finish splitting and only a cap formed. I still have another 30+ cats that are between third and fourth instar. I live in So California and I'm wondering if I just took on too big of a project. when I went to the nursery today to get more milk weed I was told that any caterpillars this late in the season probably wouldn't survive. Any thoughts on that?

Reply by Steve (Cranial Borborygmus)
Hi Tracie, If you're in Southern California, I don't think it's too late for your caterpillars. I'm in Santa Barbara, California, and we've just had several Monarch butterflies laying eggs over the past week or so. We haven't had very many caterpillars this year so far, so we have a LOT of milkweed available and I'm expecting a bumper crop of caterpillars. I find they aren't really seasonal here, but instead can pop up any time of the year. What you are doing does sound like a big project, especially collecting 150 eggs. Wow. I know how frustrating the tachinid fly can be. We've had that problem with the few caterpillars we've seen so far this year. As for ten or so caterpillars not finishing splitting and only forming a cap, that is strange! I only had that happen to one or two. Ten is a lot! I wish I knew why it happened, but so far I think it's just guesses as to the cause. Anyway, I wish you good luck with your remaining cats!

Reply by tracie on Wednesday, November 22, 2017
I wanted to follow up on my original message! I released 41 monarchs over the past 2 weeks!!!

Comment by Ange on Saturday, November 18, 2017
I have one that is failing to pupate at present (in New Zealand). It is the last of 30 to pupate and it attached very close to another formed chrysalis. It appeared irritated the entire time it was j hanging and twisted about like they do in response to movement or being annoyed by another caterpillar. I believe that through this twisting it pierced its skin and fluid has been leaking since. I think the caterpillar is now too exhausted and or internal environment is too dry for it to shed its skin properly.

Reply by Steve (Cranial Borborygmus)
Hi Ange, Thanks for your comment and report from "down under". It's neat to hear about Monarchs in New Zealand! The good news is that you had 29 caterpillars successfully pupate (wow). Sorry to hear that the final caterpillar did not. Thanks for your efforts for the Monarch!

Comment by Anita Parker on Saturday, February 03, 2018
This just happened to one of mine! Picture #2. I raised it inside, it was cool, in a butterfly house. Only this one out of 15. No signs of weakness in it's development, no odd behavior. Fresh leaves every day that I first rinsed with water; clean cage...pesticide free milkweed., organic soil. One odd thing was it didn't climb to the top of the cage to make it's chrysalis, it formed on a paper that lines the cage...paper was folded so it made a sort of "overhang", so caterpillar was hanging with plenty of room above surface, and had a tight bond to the paper. After one day, I cut the paper to remove the caterpillar thinking it was dead, and it began to's still alive. I'm rather upset needless to say. I spritzed it with water, no idea what I can do.

Reply by Steve (Cranial Borborygmus)
Hi Anita, Thank you for commenting and sharing your experience. I still don't know and haven't learned why some caterpillars only partially pupate and then stop, so I don't know what happened in your case or why, but I completely understand how frustrating and upsetting it can be. At least it was only one caterpillar and not more. Thanks again for commenting, and keep up the good work!

Reply by Anita Parker on Wednesday, February 07, 2018
That caterpillar lived until today, I kept hoping it'd finish pupating, but it never did.
Yes, thank goodness it was only one!
I've now released about 200 Monarchs, since I began last April. In my very last "batch" I had many that were born weak, and a couple with crumpled wings. Some looked fine, but never flew. So after that, I took a break, sterilized my butterfly house, cleaned all of my milkweed, and prepared for a fresh start.
These 15 that I have now are my first ones of 2018. The FIRST one emerged from it's chrysalis this morning, a male, appears to be healthy. :) :) :) I will release him this afternoon, it should be a beautiful day for it's first flight. Sunny and 75-ish.

Comment by Sheila on Monday, February 12, 2018
I'm in southern California - I have been seeing some tachinid affected caterpillars not make it coming off my milkweed plants, (although many have because I have constant butterflies and chrysalis' around my yard), but I decided to bring in and raise a few eggs - I have 3 "healthy" cats after a couple of weeks, one is in his 5th instar, HUGE, eating incessantly, and then began wandering around his mesh cage looking for a "spot" on the top! I've been excited all day, but tonight it looks like he may have spun a silk spot, but never turned around to attach his behind!!
I'm worried - that should have happened by now, right ?? (2 hours later)...what do you think???
eeeek! thank you for any feedback - I'm obviously very new to this - I followed every possible strategy to keep them healthy.... :(

Reply by Steve (Cranial Borborygmus)
Hi Sheila, I'm not sure what is going on or what you could or can do. I think all you can do is give the caterpillar time and see what happens. I've had similar experiences and some times they make it, but other times not. They can die from multiple things, not just the tachinid fly. It can be frustrating, but as long as some make it, it is worth it. Good luck!

Reply by Sheila on Monday, February 12, 2018
Steve, Thank you so much for your reply!! I've just got to say, I woke up this morning to a perfect "J" at the top of the cage!! (sigh of relief!!) This caterpillar thing is NOT for wussies!!! Your quick response much appreciated...

Comment by Pixie on Saturday, February 24, 2018
Im as new to this as 1 can be i found a chrys on my grams house was watching it when a neighbors cat knocked it off so i taped it into a clear plastic jar should do alright I assume. But now i have 2 more cats that where just starting j phase when they got knocked from their silk stem thing so i grabbed them an put them in the jar ive tried getting them to butt grab a q tip but so far only 1 seems to be holding on the bigger one keeps wiggling an falling off onto the paper towel pillow im thankful i put in the bottom should i keep trying to get the big one to grab the q tip or just leave it be? Any helpful info would be great ive been giving myself a crash course in monarch rearing thats how i found out about the qtip thing an the pillow. I really want these guys to pull thru ive wanted to raise butterflies since i was a little kid.

Reply by Steve (Cranial Borborygmus)
Hi Pixie, Thanks for your comment. I'd never heard of your "Q-tip trick" before, so I don't know what to tell you. But it sound like it might work, so I wish you good luck!

Comment by Ann Rupp on Saturday, May 12, 2018
This is to thank Karen Essig for her comment last September and the pictures posted. Your pix #1 is exactly what I have with one of my chrysalis! I'm on this site looking for an answer and am gratified to know that perhaps the little guy might make it to eclose. I was almost ready to pitch him and give my mesh cage a good cleaning but I have 4 other chrysalis that are anywhere from 1 - 6 days from possible eclose. So may interesting comments here...I'm glad to have found you. This is our 2nd year of raising monarchs and we're hooked!

Comment by Cathy Gard on Thursday, July 05, 2018
I am in Kansas and raised and released 100 monarchs last summer and never saw one die after beginning pupation. I brought the first two cats in I found this year, and one pupated fine, and the other did what picture #2 did. Not a great way to start the year! In my garden, they all get eaten by wasps or killed by flies, so I try to bring them in if possible.

Comment by Coral on Saturday, July 07, 2018
I have been raising monarch's for years. I grow my own milkweed and have quite a large patch of it. No chemicals are used in my yard ever. I also wash and dry my milkweed before giving it to the caterpillars. Today was the first time I ever saw a partial pupation take place. It was quite the sight and I hope I don't have any more issues this summer. I was given 3 cat's from a coworker who found them on some roadside milkweed. I also am raising my own from eggs I collected. The 3 she gave me of course were kept separate from mine. One I was given died about a week ago from either vomiting or diarrhea. Not sure as it was leaking a green fluid and seemed to almost be convulsing..? I separated it immediately from the other two, and it passed away a day later. I never experienced that either in my time raising them. The other two seemed fine. They were eating, moulting fine, were in an enclosure that was quite large and roomy, had plenty to eat, and I do excellent housekeeping for them.. Clean their enclosure daily and fresh rinsed/dried milkweed daily. Both were sturdy husky caterpillars. Last night both started to hang in their J. They were put into separate smaller enclosures yesterday as they seemed to keep fighting when they were looking for a spot to attach and pupate. I have moved cat's before when I knew they were getting ready to attach, as I don't want the cat's still eating to disturb them once the process starts. I have never had problems doing that either.. So this morning I expect to see healthy pupating caterpillars and instead I see both lightly partiality pupated. One was dripping green fluid, the other was dripping a darker brown fluid. One looked like pic 2, the other ended up eventually hanging as in pic 3. I was rather shocked, that is how I ended up here after googling causes. My cat's have been inside as in Ohio we have had quite the heat. Today and yesterday it wasn't bad, ( 79-80) but we have been between 88-95 . My chrysalis's have been inside too. I just had some eclose today. They were released this afternoon and were quite beautiful. My house temp is around 74-75.( AC). I haven't had any health issues with my egg raised cat's, and have already released several butterflies this summer. I don't know what to think of this all. I am thinking it's an illness/virus. We don't seem to have tachinid ( spelled wrong?) flies where I am at. But these 3 were given to me. The person lives out in the country while I am in the city. I am hoping someone can give a definite answer one day. It's rather sad for these caterpillars.

Comment by Teresa on Thursday, July 19, 2018
Here in Ohio as well. I am very worried about this year's group. My cats are failing to pupate also. I am afraid that there is something affecting this entire generation in Ohio.

Comment by Peggy on Wednesday, August 01, 2018
NE Ohio, having the same problem. Have been raising Monarch's for 3 years and have had some deaths but nothing like this. First mistake I made this season was putting Frontline on my dogs. Had no clue it could affect my caterpillars. Lost 7 of them in one night from poisoning. :( I've since kept my dogs out of the area where the caterpillars stay in our home.
Washed and sanitized their cages, use disposable gloves when handling them or their food. Not much more I can do. But the issue now is that each of the last 4-5 caterpillars began to form their chrysalis but didn't finish. They end up with this weird elephant man kind of look on the back of their heads where the process stopped. Have another one who just did the same thing. Silently cheered him on as he started twisting around and the process started, had been hoping this would be the one that would be strong enough to fully form the chrysalis. Sadly he's having the same problem. I'm probably in denial but will leave him/her overnight to see if it makes progress. Have my doubts. I hope someone can come up with an answer for why they do this. Out of around 36 eggs collected, have only released 7 butterflies.

Comment by Kathy Olson on Wednesday, August 08, 2018
I've just encountered this with 3 of my caterpillars out of 30 not being able to properly pupate. I'm thinking in my case it is stress but again it could be the temperature in the foyer. I plan to mix things up a bit and try something else...using an aquarium, instead of the mesh and separating them out so they have more room. I'm in Illinois.

Comment by Linda on Monday, August 13, 2018
Hi, I am so bummed!! I have just started to raise monarchs in my yard & have had 5 of my cats start to pupate. They are in the J shape and then they just shrivel up and die. Was reading all the previous posts and see that others have gone thru the same thing.

Comment by Steph on Thursday, August 16, 2018
Hi. I have brought caterpillars in to raise on and off for years up here on the north shore of Lake Erie. I came upon this site because yesterday, I had my first caterpillar fail to pupate and I was looking for causes. He looked very much like the picture of egg 2 only he did make the J, but was only able to wiggle the skin about one quarter of the way up. This summer has been very hot with the temperature being in the high 30's (90+) most days, but the cats haven't seemed to mind so far. Thank-you for all the comments and replies. It is all very informative. Fingers crossed he'll be my only casualty. I did release two butterflies yesterday which helped brighten my day!

Comment by Lesli on Saturday, August 18, 2018
Just want to add to your data: I have had one cat fail to attach properly and found it in a large pool of green goo on the bottom of the container. The goo was coming from its back end, the gold band had formed on the cat, and its mouthpart end was all intact. I live in Minnesota and raise my cats indoors from eggs found outside.

Comment by TINA INZANA on Wednesday, August 22, 2018
Rochester, NY I've raised monarchs for 40 years. This has been a good year number-wise but I have had losses at a rate I've never seen before. My first 30 all failed to pupate more than a quarter inch, otherwise healthy and fat. Seemingly healthy butterflies not able to fly. I have a lot of experience and I'm confident it is not caused by the home environment. I have over 500 to go in various stages, egg to darkened crysalis. My euthanizations have been alarmingly disproportionally extreme.

Comment by Emily on Thursday, August 23, 2018
I also had a caterpillar that looked a bit like caterpillar #2. He was in a J, split his skin behind his head, but then was brownish near the top of his J (feet, perhaps). He was alive when I removed him, and he eventually turned to brown mush and oozed a green liquid when I froze him in a plastic bag. Very odd. From western PA and raise cats inside from cats and eggs found outside.

Comment by Bevan on Friday, August 24, 2018
I've never raised or looked after a caterpillar/butterfly before and we found a monarch Cat in my mother's yard in St. Louis and took him in for my kids to watch. We were driving back to CT and had him in a large glass container with plenty of milkweed, I cleaned his bowl with fresh food each day. We had him only 36 hours before he started his J hang. He also started to pupate after about 12-18 hours of hanging, but stopped with just a small patch exposed behind his head. Like picture #2. There is a dark liquid below his hanging body and an occasional drip.
After reading all of these posts, I am going to chalk it up to stress and/or temperature swings. I've learned so much from reading this post, if we ever attempt to care for another caterpillar I will definitely not take an older Cat from the wild and I will give it a more consistent environment!

Comment by Jamie on Wednesday, September 05, 2018
Hello, I began collecting caterpillars in hopes that I could help them survive. In one day I found 5 large and 9 baby caterpillars. By the next day, all 5 of the big ones were on the top of my mesh cage in the J shape. This morning 4 had made chrysalises and one was just starting his (looked like he had a green cap on his head). To my dismay I had to leave for work so I could not watch him spin. When I returned home he had not made it much further, and was hanging straightened out. I too am stumped as to what went wrong. On another note...before I began taking them in I had 10 chrysalises hanging around my milkweed area. One of them was black for three days and misshapen and I was sure it was a goner...until I was sitting on my porch and saw that it was trying to emerge! He could not get even half of his body out, the poor thing was trying so hard and my bf did everything he could think of to help it along, but nothing worked. We could see that he had very small, barely any wings to him, so eventually my bf euthanized it (without me around of course). We can only think that it must have been in the chrysalis too long and was deformed. Anyone else experience this?

Comment by elizabeth on Monday, September 17, 2018
I brought into my small storage room approximately 25 caterpillars, one fell after making a crystallised and 21 have all formed but one caterpillar is hanging but failed to form into crystallised, it has been at least two days it is no longer a j but just hanging, I just misted it, it seems to be dry and card green, I am in port Maitland nova Scotia, temp here is average 70s, hope all of my crystallised hatch normally as these butterflies will be heading to mexico, heard large swarms heading down from great lakes area good to hear

Comment by Adiema F Ebanks on Friday, November 02, 2018
I strongly believe that pesticides are the reason for the caterpillars not able to change. I been raising Monarch for 4 years now in Evans GA, and this year I lost most of my caterpillars. Barely any could change successfully, and die. They struggle just to get the skin to split by the head and then die. The skin only stretch because they been pushing the skin up All my Milkweed I grow in pots. I was running low on Milkweed and a friend of mine who been raising caterpillars too, took around 40 of my Monarch cats and raised them successfully. All my Milkweed grew back and now my friend had Monarch laying eggs in her yard and she picked up 8 of my Milkweed pots and raised successfully 50 healthy Butterflies. Then I had a Monarch laying eggs again, and with my Milkweed mostly grown back, some of the same pots I gave to my friend, most caterpillars could not change. I also had a lot of eggs that just turned black, and died. Dried up. I raised the surviving cats inside the house. They ate well, got fat and round, acted totally normal. We use no insect spray etc. I hardly touch them, and when I have to move a cat I wash my hands(and under my nails)and barely touch them (use little milkweed twigs). I picked them when the Butterfly just lay the eggs. So no flies or wasps could got to them. I wash my Milkweed off very well, I lay netting over the soil so they do not come in contact with the organic soil I use. I use Butterfly enclosures the netting do not let any small insect in. My friend and I been back and forth on what could be the issue, and we believe that the Butterfly that is laying the eggs somehow got compromised. We believe that, someone is using a pesticide that is the cause of the cats not be able to change. Maybe even just drinking nectar from a treated plant could cause some defect. We are no scientist. But for 3 years I never had this issue, and nothing in my house or garden is the cause of this.

Comment by Ursula on Tuesday, January 15, 2019
HI, I have 5 that failed to pupate last night. We are in central Florida, on the gulf coast, about an hour south of Gainesville. Some of the nights have been cold, maybe in the 40s, so last night I took out a space heater. They all formed Js, but then went limp and are just hanging there, like your caterpillar #2. Very sad. It could also have been food stress, if not the cold. I relocated 30 of them a few days ago, to someone else's yard, and missed these 5. We were down to sticks. Would be very interested in your opinion, as I'm trying to learn more and do better next time.

Reply by Steve (Cranial Borborygmus)
Hi Ursula, Thank you for your comment. I don't know what might have happened, but I think you are correct to guess that it could have been the cold and/or lack of food. I didn't even know that Monarchs were active in Florida in January. I thought they would all be down in Mexico for the winter. That might be part of the issue also, but I don't know.

Reply by Ursula on Tuesday, January 15, 2019
We have a problem with non native milkweed that doesn’t die back- some say it prevents them from migrating. Others say we have non migratory butterflies. I’m not sure- maybe both are true.

Reply by Ursula on Tuesday, January 22, 2019
Caterpillar update! So amazed. The three cats that failed to pupate, that hung in their Js for a week, that i was sure were dead? I thought they didnt make it, either from insufficient food or from cold? I never got around to removing their sad little corpses, and today i happened to look up and omg! They weren’t really dead- it seems they were just dormant!We have 3 chrysalises! Nature is beyond amazing. I am in awe...
I thought you’d want to know!

Reply by Steve (Cranial Borborygmus)
Hi Ursula, Wow! That is great news. Thanks for the update!

Comment by Noelle Isenberg on Thursday, January 17, 2019
Found this very informational thread as I was searching for some answers to why my cat didn't pupate completely. I've been raising in Redondo Beach [Southern California] for 6 months now and this is the first time it's happened. I brought in 4 from the garden due to rain this week and I'm wondering if the temp and moisture had something to do with it. I have brought in some from rain before and they were all successful. As this is the first time of losing one mid cycle, I'm bummed. I know that geeen goo is the magic cells that in turn help them to become butterflies. I did notice it didn't make a successful silk spot as well and it stopped contracting mid way through. I'm so grateful for all of you who raise and share vital information! It's such a good way to track data!

Comment by Sandy Jones on Monday, April 22, 2019
I came onto this thread to see if I could find out why 2 of my cats didn't pupate completely. I was surprised that so many people have experienced the same thing. I have an outside milkweed bush & live in South Australia where we are having very dry conditions. I've watered the plant a few times & it is big with plenty of food for the cats to feed from so not sure if it was through lack of rain. I've found 9 other completed chrysalises on the bush & will leave those 2 that are incomplete and appear dead and still hanging in the J position but will keep an eye on them to see if they finish to pupate like its been stated has happened before to a couple of other people.

Comment by Erin Tayyar on Tuesday, April 23, 2019
This same thing JUST happened to me. Caterpillars would go to the top, try and do their J, and then just die. Some of them would try to pupate and not be able to split the skin past the head area and I found them hanging just like egg #2 and #3. I have never seen this in my years of rearing. I have no idea. Some had a pool of black liquid at the bottom of the cage. Maybe NPV or Pseudomonas? None made it. I have since sterilized everything I use for rearing and am gonna give it another go. I was able to release 200 Monarchs this past Fall!

Comment by Elli on Monday, May 13, 2019
Found this page while trying to understand what just happened to one of my cats. I live in Anaheim, CA. This is my first year raising monarch cats. I have 2 condos and put no more than 5 in each to keep from overcrowding. All their milkweed is raised with no pesticides, and they have plenty of it, and they are in a clean environment. So far 4 in this batch have pupated successfully (although one hung himself to the side instead of on top, no sure if the side that is touching the way will form ok), but one tried to shed his skin yesterday, exposed his head and about 1 third of his body, and then that was it. It's been almost 24 hours, and I just noticed some bright green liquid dripped. Should I assume he is dead? Strange because this cat was a real nuisance - he kept crawling all over the other chrysalis - I thought he was trying to eat them at first. He was very frantic in the hours before he made his silk button, which he made right next to another. It was like he felt he was running out of time. I haven't seen this much agitation in any of my other cats. Any insight would be great - thanks!

Comment by Candy on Thursday, May 16, 2019
Did anyone ever discover the cause to this? I just had two (3 days apart) caterpillars suffer the same fate as #2 and #3 in the pictures above. This is my second year at raising. I had some issues with T. Flies last year and Monarchs haven' t come in full force this year yet. IF it' s from nursery bought milkweed...will water washing prevent it or do I need to treat leaves with bleach solution prior to feeding?

Reply by Steve (Cranial Borborygmus)
Hi Candy, Thanks for your comment. In my case with my caterpillars in the pictures above, all of my milkweed is grown from seed and I don't use any pesticides in my yard, so that's not the cause in my case at least. I posted these pictures because I had never heard of this happening, but based on all the comments I've received, it is not that uncommon. However, there are lots of theories on why it may happen but I don't know if anyone knows for sure, or if it is always for the same reason. Hopefully most of your caterpillars will continue to pupate successfully and turn in to beautiful butterflies. Good luck!

Comment by Tamara on Thursday, May 30, 2019
Been raising monarchs for the past year with no problems, but now some of the caterpillars hang and don't start turning into a chrysalis. They just die. In another group, the chrysalis starts to go from green to yellow and they liquify and die. One had a long string of silk hanging from the chrysalis. Very frustrating. Not sure why this is happening or what to do to stop it.

Comment by Shannon on Thursday, June 20, 2019
We have this too. In Michigan: have milkweed all over our front yard, no pesticides or spray. Raising them indoors; wash the leaves and pat dry. Last summer most of our caterpillars had the #2 or #3 problem, didn't know what to make of it. Our milkweeds die off and then regrow each spring, so it's fresh. I have had this happen with ALL of our cats this year so far. Ordered 10 from a supplier; they ate well, got huge and fat, acted normal, made a J, and then stayed that way 2-3 days before going limp, straightening, and dying. Second set of caterpillars, 10, kept separately and harvested as eggs from a nearby roadside field (no known pesticides here either, rural area alongside the road we live on). Raised and fed indoors on milkweed that has been washed and dried. These are sequentially J-ing now, and then they stretch out and die. No successful chrysalises. No signs of tachnid fly. I would think the washing would reduce the OE or NPV or other infections. I wash my hands. Sanitized/bleached and washed the containers (plastic tanks with lids) between last summer and this one. Transfer them with the side of a toothpick. Reasonably stable indoor temperature ~70s. Before last summer, we raised many many and released them .... it was almost too easy! This year it's about 100% failure and last summer was close to 80% failure. I am ready to give up. Anyone know of a university that might be studying this phenomenon? It sounds like nearly all of us here are seeing this problem.

Comment by Chuck on Sunday, July 14, 2019
Well, like everyone else I found this thread because we're having the same problem, skin begins to shed but then the cat gets stuck and fails to fully form its chrysalis. We've been raising monarchs for 4 years now, released 118 last year with ~80% success rate. We collect eggs and first instar cats from our garden, and I feed them milkweed that is either from our garden or from a site I've used for many years now. Fearing pesticides I always wash every leaf top and bottom under cold water, rubbing thoroughly. Deaths are of various causes, black eggs parasitized by wasps, the occasional first instar cat that just shrivels up, last year we had a Tachinid fly and an anal prolapse (never want to see that again, poor guy) , and now this year I just had a rash of Black Death NPV virus kill off 10. Surviving cats were moved to fresh leaves while containers were washed and bleached. We raise them in our garage so no direct sunlight, temperature in the 70-80F range and humidity in the 65-80% range (I have a probe by our nursery. A few times this year they did eat their leaves down to the stem before I made it home from work, but once I gave them fresh leaves they happily started munching away. After having 4 fail to fully pupate in just the past week I did try "helping" one but it appears their new skin underneath is not properly formed, so I'm thinking the failure to shed and pupate is just the surface of a much deeper problem. So what could it be? Environmental seems tough unless it's an extreme hot cold or dry. Right now I have one stuck with just his back split and my garage is at 77F and 64% humidity. Pretty comfy compared to the extremes outside. Virus or parasite? If it is it's unlike anything documented. Cats grow fat and behave normally. Nothing emerges from the body, but maybe NPV infection late in development just before it pupate. Insecticides? This I fear could be an issue. Despite not using any on our property and washing every leaf chemicals that can drift in the wind and are "rain resistant" can be on the leaves. If the chemical messes with some stage of development this could affect pupating without affecting anything else. Lastly genetic? One of the parents could have a genetic mutation that messes with pupating. It's a very complex stage in their life cycle and a lot of ways it can go wrong. Unfortunately nature is cruel, these guys don't make it, the bad gene doesn't get passed on, just how it works. If you collect eggs in batches which are likely laid by the same female, and collect food in batches, it can lead to a clump of failures if it's pesticides or genetic. A virus can spread silently in your colony, and cats that are raised together experience the same environmental conditions. So unfortunately I have no clue what it is and all options still appear to be on the table. Collected 49 eggs yesterday alone. Hopefully things start improving.
I did want to add one unrelated comment. A recent study by a group in Chicago showed that monarchs raised indoors in the autumn are unable to properly orient southward to migrate. They recommend either only raising summer generations or raising them outside. Working hypothesis is the sun tracking across the sky while in the chrysalis helps wire their brain up properly. I've noticed all our chrysalises are oriented north-south. . Also they did a genetic analysis of commercially available monarchs showed they are unlike any natural wild population and when raised in the autumn they do not develop the migratory phenotype nor are they able to orient southward, so only raid cats you collect in your garden.

Comment by John Hockers on Monday, July 22, 2019
Very interesting message thread. I live in WI and just had two caterpillars fail to pupate as well. As a kid, I raised hundreds, if not thousands of Monarchs. I experienced many of the common issues, most notably death by maggots. I found that it was actually quite easy to protect them from flies by collecting them in the first or second instars and then housing them in fly proof caterpillar homes. But I never experienced a half pupated caterpillar before. For the last couple of years, I' ve been raising Monarchs with my school age daughters. Everything was fine until this summer. I have a theory as to what might be happening. I have always fed my Monarchs common milkweed with its big and milky leaves. But as many of you know, caterpillars in the fifth instar are ravenous and it can be hard to find enough plants to feed them. This year I planted three new varieties of milkweed in my garden, from roots that I purchased at Home Depot. They sell them under the name "Monarch blend". I suspect that they are genetically modified to provide better germination and better flowering. I raised a batch of six caterpillars on these new milkweed plants. They all grew well and didn't have any problems until they tried to pupate. Two have died and two have formed chrysalises so far. The last two are still in the fifth instar. I'm wondering if GMO milkweed might be the problem. The leaves are smaller and seem to contain less "milk" in them. Could this be causing some type of "milk" vitamin deficiency that only manifests when the caterpillar attempts to pupate? I would love to hear others thoughts before I rip out all of my GMO milkweed.

Comment by Laura on Wednesday, July 24, 2019
First year raising and my very first caterpillar had this happen yesterday (raising outside in mesh cage, fresh milkweed, eggs or 1st instar collected from garden). So, needless to say, I was very excited to see the J and the split and then all day long I just watched the blaze and the strangely elongated stem just hang in stasis while I searched for answers. Factors I outside Chicago and we had BEASTLY heat for a couple days last week with heat index around 106, 108...also had two brutal rainstorms that week with crazy wind. The rain didn't hit them but the winds did. And then 2 days after the 100+ heat, we dropped to 59 at night. That is basically a 50 degree drop in a couple days if you count heat index and the day of the attempted pupation (is that the term?) it was quite breezy so add drying winds. The cat looked like it was stuck with the skin in the middle a bit like a corset. We don't use pesticides but neighbors on either side do use TruGreen although the location of the cage keeps them away from direct spray (we all have acre sized lots). Thoughts? I am reading about so many losses for everyone and now am going to be fretting when the next attempt happens, likely in the next couple days.

Comment by Candy on Saturday, August 03, 2019
I'm currently working on raising caterpillars. So far I haven't had any issues with pupating 9 of them. But one of them decided to hold on from it's silk button by it's abdomen legs, instead of the hind ones by it's butt. It's basically attached to the side of it's raising container, (which I had just moved inside the laundry basket to find a hanging place). I think maybe he/she felt he/she had no time to lose or to find it's way up. I'm scared that it's not going to pupae properly. And I think it's late in time to try to move it. Anyone with similar story?

Reply by Steve (Cranial Borborygmus)
Hi Candy, I've never heard of this before (a Monarch caterpillar hanging from it's silk button by it's abdomen legs instead of it's hind legs). I would leave it alone and not risk handling it at this point. Hopefully it's just temporary and the caterpillar will move and hang normally, and then pupate. Let us know what happens.

Comment by Jennifer L Gokey on Wednesday, August 07, 2019
You all have no idea how happy (and sad) I was to find this thread, as we just had this happen today with two of our big fat caterpillars! There was a sudden boom in monarch caterpillar population here in our small town, and with all the struggles they have been going through, it was a delight to see so many! However our country town has a tendency to mow the sides of the road, and about 2 and a half weeks ago, they completely stripped the side of my road up to 5 feet away from the roadside. This left MANY of the wild milkweed completely decimated (at least on the road side) and prior to this my children and I had picked up a very well ventilated big mesh enclosure, as we had thought about attempting to raise caterpillars.
So we wandered up and down our road, looking at the damage, as my youngest daughter (age 7 and a half) insisted we see if there were any caterpillars left. What we saw was absolutely horrible. So much milkweed was laying on the ground, stalks broken, ripped up, or just all around looking mulched. We managed to rescue 12 caterpillars that were sitting on the broken dying plants (most of them were newly hatched or in their 2nd instar) So we carefully picked them up by the leaf or scrap they were on and put them in the enclosure. We then found at least 14 leaves that had eggs on it, and added them in as well.
Up at my in laws house, we let the back half of our property go completely to the milkweed, and goodness does it THRIVE! I am talking leaves no smaller than 5 inches across at their widest point, and growing sometimes as tall as my 5'7". We have been spending the past 2 weeks raising the caterpillars we rescued. I have taught our girls that we are to handle them by hand as little as possible, it is better to try moving them while they are on a leaf or stem as I do not wish to stress them out, cause harm or damage them in any way. We make sure that all of our milkweed comes from my inlaws. I am incredibly meticulous in gathering leaves, as I want to be sure we do not accidentally bring home any more caterpillars, egg or not. I also check over and over to be sure there are no mites or aphids of any kind, and that the leaves are carefully washed and dried before feeding them. Now, over the past couple weeks I try my best to be very slow and careful when opening the enclosure, as moving the zipper causes the caterpillars to become alarmed, or our J caterpillars to be scared and curl up, using up an unnecessary amount of energy.
The first caterpillar my eldest daughter found was successfully raised from egg to butterfly, and was released Sunday afternoon after its wings had dried enough.
We then encountered a strange problem with two out of 4 remaining chrysalis's that I could not for the life of me find any information on. One of them, went from beautiful green, to having a big, fat smooth brown splotch on the top/front side of the chrysalis. The other, was a very small chrysalis, which also had a brown spot, but the spot was much darker, very small, and looked to be indented. We placed them in quarantine (very carefully) and neither chrysalis survived.
Now, today, we ran into another sad problem, one that I have seen pop up numerous times while reading all (yes all) entries here on this page. Two of our big fat caterpillars looked to be doing very well. They were always eating, never running out of food, and we were sure to change out the newspaper (carefully and with as little stress as possible) every other day to make sure there was as little fras in there as possible. Then the big caterpillars started acting different. They were wandering around the enclosure, they would make their little silk highways if you would, at the top of the enclosure (which is a clear textured plastic so the kids can see inside) They would stop, heads moving back and forth much like the previous caterpillars would to start anchoring themselves, then move on to a different location. Finally, finally, they chose a spot and hung upside down. We watched as their skin slowly turned green and they worked at trying to turn into a chrysalis.
While I was at work today, excited about the prospect of these two forming a healthy chrysalis (the other 3rd fat one turned into chrysalis form the day before and hatched the same time these two did) the girls remarked something odd had happened. I got home and checked on them. Both had only the head part (bottom part) of the chrysalis formed. The one in the back part of the enclosure hung straight and limp, and there was barely any movement at ALL (very different from the fascinating 3rd one which wiggled and pulsated until it turned into its chrysalis) eventually this one just stopped moving all together and just seemed to die on the spot. I ended up having to dispose of it, as all signs of life were just gone. Also, its entire body turned incredibly dark, almost black, and I worried if I did not remove it it would turn to goo and infect the other healthy cats with whatever it might have had. The second one, closer to the front of the enclosure, also has only formed the first small section of the bottom. This one is still in partial, loose J form. I quarantine it in a smaller enclosure, as its body is also darkening and it looks like it is having a very hard time moving and getting into chrysalis form. I will check on it in the morning and see if it is still alive.
My questions to you is this:
1.) Do you know what caused the first two chrysalids to turn brown in one area?
2.) Do you think the other two big caterpillars could not form their chrysalis properly due to maybe being stressed or moved around too much? (my kids know to be careful but I know that the enclosure was gently shaken a few times during the J formation due to the table it was on being knocked into)
Any feedback or other information would be welcome, I can see about getting pictures on the computer of the ones we have. In the meantime, we were thinking of releasing more of the bigger cats to the wild milkweed up at my in-laws, now that they are bigger and have been given a good head start on their life cycle. (we released quite a few already because we knew that any more than what we had and we would not be able to keep up with feeding them enough.)

Comment by Kristen on Wednesday, August 07, 2019
There is a certain type of pesticide called an IGR, or insect growth regulator, which causes pupation problems just like your photos show. It's an insect hormone that works by preventing larvae from becoming adult insects. They're used outdoors on plants/lawns, on farm animals to control flies and lice in barns, for indoor insect infestations, and in flea drops/collars for pets. Petting a dog or cat that's been treated can easily transfer the IGR to everything handled afterward. I don't think the caterpillars even have to physically touch the IGR; it only has to be in the same room to make them unable to pupate (like how a couple drops of flea medicine on the back of the neck works on a pet's whole body).
It's also possible that a female butterfly feeding on flowers in a "grub controlled" yard or on plants treated with insecticides may suffer IGR damage to the eggs she carries and lays on your untreated milkweed.

Comment by Lisa on Saturday, August 31, 2019
I'm so glad I found this thread. I've been raising monarchs for about 10 years, and I just had my third one fail to pupate this year. This has never happened before, not even once. I also lost one that failed to emerge between the 3rd and 4 to instar. I have my own milkweed, no pesticides in my yard, no other animals. I'm also suspecting that the eggs aren't hatching as well, since I collect a lot of eggs but only end up with a couple cats that hatch out per batch. This black liquid with the failure to pupate is really suspicious. In Chicago suburbs.

Comment by D War on Tuesday, September 10, 2019
This past weekend I volunteered for a Monarch festival. Basically it was an event regarding rearing and preservation. I was placed in the Milkweed harvesting since I was one of few volunteers who knew about the actual plant since I have my own crop. I had a woman who described the partial pupate in some of her Monarchs. After 7 years of raising them, I have never had it happen. After the festival, my daughter and her friend were given a tropical milkweed and a caterpillar. The friend's caterpillar went into J that night and today partial pupated. I don't know what will happen with my daughters since it's not ready but I have a theory. I spoke with many people in the surrounding area whose Monarchs preferred Swamp as opposed to Common Milkweed. Mine won't touch Swamp. We all live in the same state however I live an hour west of most of the people I spoke to. Could this be an area thing? Even from city to city, the caterpillars had different problems and preferred different food. Last year all my caterpillars died early yet a friend in another state had no problem. This year I released 85 and counting with very few dead loss. I think I had only 4 infected with Tachinid, 2 babies who just didn't make it and one who could not shed to the next instar. Other than that no major problems and I never had one partially pupate. The friends cat is from that area, is eating tropical milkweed and partially pupated and died. Something to perhaps thing about further.

Comment by Cathy on Saturday, October 26, 2019
Hello all! I have a similar issue with Variegated Fritillaries. While Gulf Fritillary are abundant on my passion vine, I removed a few Variegated Fritillaries as cats and rinsed the leaves and had separate enclosures for each. The Gulf Fritillary did what they were supposed to do and I brought them fresh vines in floral picks daily. They J-ed up, chrysalis-ed fine and emerged are beautiful orange long wing butterflies.
Now, the first Variegated Fritillary #1 - hung as a chrysalis until half broke off leaving his abdomen exposed yet nearly fully formed-wings and all. Unfortunately my husband wanted me to help pick out new flooring and said we'd be quick. Well, we weren't quick enough. When we returned home, I could tell #1 was dead because he couldn't push against the back of the chrysalis to come out. If I stayed home, I could have helped him out I'm sure. No more "quick trips" when butterflies are concerned. V #2 this morning was in a J shape and I was enthusiastic! Then I went closer to look and recognized anal prolapse by the bright green ball he was hanging from. He still is alive and wiggles a bit and now (pm) it all black liquid that is drying up yet he's still moving. I'm going to give him some more time and hope he makes it through the night. I don't have the heart to euthanize him unless it's a sure thing that he's going to die. Right now he looks like egg 2 and I hope everything goes well. I have 2 Gulf's in chrysalis and a smaller Variegated cat munching away. The neighbors before they moved had purchased the passion vine, so there's no telling what was on it. It was small when purchased. I think I'll collect seeds and grow my own for next year. I'll let you know what happens to V #2 soon. Hoping for a chrysalis! (crossing my fingers) Thank you!

Comment by Cathy on Sunday, October 27, 2019
Well, the variegated didn't pull through the night even though he did start a chrysalis. Without this blog, I wouldn't be able to know what the bright green ball was by his anus. I rarely see any Monarchs in my area, yet as a kid (I'm 60 now) I'd see them all over the place.
Besides these 2 species of fritillaries, I have also raised 2 groups/families of the Luna Moth. An old female was laying eggs on our front door frame and I knew they would die. So I carefully laid her in a container with a small branch of Sweet Gum tree. We had 24 mature Sweet Gum trees in our yard so there was plenty of food. We eventually had them removed because the house was on a hill and they would get caught in our dogs paws. The neighborhood has plenty of the same tree.
I know I wasn't writing about monarchs, and these probably won't be posted, yet I wanted you to know how much it has helped me raising other butterflies. We are all in this together. Fly on, Cathy

Reply by Steve (Cranial Borborygmus)
Hi Cathy, Thanks for sharing your experience with the Variegated Fritillary butterflies and the Luna moth. Very interesting!

Comment by Carol Esarey on Sunday, February 23, 2020
My comment relates to monarch cats unable to pupate. I am in the Florida Keys. Monarchs are few and we understand, do not migrate. I had good success last year. This year, 100% failure with all unable to pupate. Tore out all plants and replaced from the best sources I could find. Replaced much of the soil. Bleached eggs and leaves. Kept in temperature controlled space in net enclosure. Tried to keep them stress free. Absolutely nothing is working. We have the same three Monarchs guarding and leaving eggs. At least I think they are the same ones. So frustrated. Don't know what to do. Am very interested in any and all comments.

Comment by Karan E Roberts on Thursday, April 09, 2020
My cats are not able to pupate completely. I have lost 12 of them one right after the other. No silk forms, they hang upside down- some j and some don't, but they seem to writhe in pain. It's horrible. Eventually they die leaving green liquid oozing out. Never had this happen before. I'm in St Petersburg Florida. Good supply of milkweed, no pesticides. I am so perplexed.

Comment by Kelly on Monday, May 18, 2020
Glad to have found this post. This is happening to me right now. I have two mesh enclosures full of monarch caterpillars and a large Tupperware bin for the eggs and first/second instars. I only had six milkweed outside and they stripped them bare. Too many caterpillars, not enough food. So I started bringing the eggs inside. Ended up with 137 eggs. Bought a couple milkweed to keep indoors to feed them and also started adding butternut squash. I found a zebra longwing chrysalis on the ground outside and brought it in to keep it safe. Big mistake. Never bring in a chrysalis from outside, or keep it quarantined on its own if you do. I learned a the hard way. A month later hundreds of tiny wasps emerged from it and did something to all my caterpillars. Everything was going great before this happened. No issues with j hangs or pupating. I cleared out the wasps (Chalcid wasps) and have been keeping a very close eye on things. Well the cats that were hanging already didn't pupate fully. They did exactly what everyone else is describing. When reading about the wasps it says they wait while the cat is in j hang and when it is a fresh and soft chrysalis they lay their eggs in it, where it then hardens and protects the eggs until they hatch, eat the caterpillar, and then emerge from the chrysalis. I found the wasps on my caterpillars that were hanging but I think they may have attacked the caterpillars on the ground too. I'm sure my failed j hangs/pupates are directly related to the Chalcid wasps because truly no issues prior and no issues in my other enclosures. Not sure if it could be the stress of the wasps that maybe caused my caterpillars to hang early and fail. Now I have one big ol fatty in there and I'm hoping it stays healthy. Raising butterflies is adorable if you do one or two, but once you are deep in it it becomes really gory and sad... they are so fragile and so cute.

Reply by Steve (Cranial Borborygmus)
Hi Kelly, Thanks for taking the time to share your experience (and warning) so that other readers can learn from it.

Comment by Jenny Kearns on Tuesday, August 04, 2020
 I have had a very successful season with my Monarch caterpillars. Last year I only managed to raise 5, this season I have 45 in the chrysalis stage and the last two have failed to pupate and have died and I had one earlier on that also failed to pupate. No reason as they all had the same milkweed and same living conditions. I just think it is nature's way. I can't wait for the butterflies to emerge in about 10 days time.

Comment by Christina H. on Thursday, November 19, 2020
 Hi, I've had a very successful butterfly garden over the past year but now it's become a hotspot for wasps and Tachnid flies so I try to take a few of the caterpillars I find indoors, especially now since we've been having warm days and pretty cold nights here in College Station, TX this time of year. I recently collected four eggs and raised three of them to full instar caterpillars. (One of them looked like it got stuck shedding during its transition from 3rd to 4th instar, (I waited on it for about two days)) All three formed their "J" but so far two of them look a little similar to picture #3 in the sense that their outer skin is what seems to be hanging and "stretched" out but neither formed their chrysalis. I previously raised two other caterpillars to a full butterfly in this same cage (disinfecting between batches of course) just 1 month ago, so the food source, temperature and humidity (probably) should have all been the same. I personally like the idea that genetics play a role in this happening, since all these eggs were collected after the same butterfly laid them and I did have previous success with their same environment/enclosure. Thank you all for adding your experiences and collective knowledge. it's been a pleasure to read through all your comments.


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