Thursday, September 2, 2021

Problems with Your Monarchs

This is our second year raising monarchs. Last year we suddenly found caterpillars on our milkweed in the pollinator garden! So we were learning as we went. This year we found a TON of caterpillars and, excited to share how amazing this process is, we made up monarch & milkweed care packages (large glass flour jars with mesh & rubber band at the top) for a bunch of Zac's friends and trundled them around the neighborhood. Of course, we also saved two dozen monarch caterpillars for ourselves and we are using the very large terrarium (24 inches wide x 17 inches tall x 12 inches deep) and milkweed racks & tubes from last year.

My favorite monarch-specific books are still Monarch and Milkweed by Helen Frost (picture book) and An Extraordinary Life: The Story of a Monarch Butterfly by Laurence Pringle (chapter book). I also found this new picture book which I really like for younger children, Summer Birds: The Butterflies of Maria Merian by Margarita Engle, that talks about metamorphosis in general and presents a young female scientist! It is worth mentioning that "chrysalis" is now used for butterfly pupae and "cocoon" is now used for moth pupae. The book doesn't make that clear. Note: "chrysalis" comes from the Greek for gold and "cocoon" comes from the Greek for berry or seed.

This year we had our first problem with a monarch. Sadly, of our two Js yesterday morning, one formed a misshapen chrysalis. I'm not talking about a slightly misshapen chrysalis where you should still give it a chance. I'm talking about MAJOR deformity. We gave the caterpillar 24 hours and then when I saw the chrysalis had hardened around him and he had no chance, we euthanized him. This simply means putting him in the freezer.

Sep 2

We are definitely still pretty new to this hobby, so I spent hours yesterday researching what might have caused this very unusual deformity. And I thought I'd make a post with some of the helpful resources I collected. None of them described anything like what I saw, but it was very educational all the same. If anyone else knows of good resources for those who are raising monarchs and run into problems, please share.

Guide to Monarch Instars

Monarch Chrysalis Problems, Surprising Solutions, and Normal Development
blog post -

Common Monarch Ailments 101
blog post -

blog post - thebutterflymusketeers

"these monarch caterpillars failed to pupate (turn into a chrysalis)... why? what happened to these caterpillars?"
long and detailed thread -- VERY interesting and informative

By the way, when I was trying to get photos of the strange shape shortly after he went in, I'm positive that I could see the butterfly's orange and black already inside this chrysalis. Which means that they don't dissolve themselves and turn into goo and then reform. This article backs that up.

Local scientist unravels mysteries inside a butterfly chrysalis
article -

Sep 1


Sep 3 - 8:30 am

This morning, Sep 3, I woke up to another monarch having problems. The closest thing I could figure out based on all of my research for the problem above, is that the first caterpillar somehow got silk around himself and then wasn't mobile in the way that he needed to be to form the chrysalis correctly. This seems to have happened again. This caterpillar tried to go into his J hang, and I can clearly see that a thread of silk is attached to his antenna and he is frozen in place. I struggled with whether to try to snip the strand of silk so that he could curl properly because 1) he seems too little to be on this step and 2) I have two cats that are newly J hanging on the top of the terrarium and another that is getting organized right now to hang there. If I disturb those three then they may not make it. The little guy who is stuck in his silk will most likely not survive anyway, and I would run the risk of losing four. So, sadly, I'm not going to disturb him. I need to let the other three make their buttons securely in peace, especially if something is going wrong with the silk process in my monarchs this year. Here is the picture:

Sep 3

Sep 3 - 10:30 am

I have now figured out what made the long strand that looked like silk. That caterpillar was infected with a Tachinid Fly (Common Monarch Ailments 101). That white strand of silk is one of the telltale signs but I didn't know enough to know it. However, at 10:30 am I SAW a tachinid fly larva emerging from the dead caterpillar. Initially it looked exactly like a small bead of the silk bubbling out and oozing down the body of the caterpillar. By the time I cut the stalk and removed the caterpillar, the maggot was climbing fully out. I laid the milkweed stalk down outside and the tachinid fly larva quickly tried to wiggle away. I disposed of it. Zac called it a "bad guy."

But, surprisingly, very strong arguments can be made that tachinid flies are beneficial insects! Interesting how the natural world works.

dead monarch caterpillar (L)
tachinid fly larva (R)

So, now I have an explanation for my second sick caterpillar. Still searching for insight on what happened to the first.

Sep 10 - 6:30 pm

This year I had three caterpillars (besides the two above) die while hanging. And I had two caterpillars die while in their chrysalis form. One turned black almost immediately, and the other turned brown after several days. Based on photos from CHRYSALIDES: THE GOOD AND THE BAD, I euthanized those (most likely already dead) monarchs.

this caterpillar was the last to go into his chrysalis - Sep 7

the black began almost immediately (photo from Sep 8)

the black today (photo from Sep 10)
second chrysalis turned brown over several days

That is a total of eight deaths this year (Sep 1, Sep 3, Sep 4, Sep 5, Sep 5, Sep 8, Sep 10, Sep 10). I have 15 healthy chrysalides and am taking two to a friend tomorrow, which will leave us with 13 to hatch!

It is very important not to let OE spores spread throughout your house or garden, since they can infect other healthy monarchs.

What Is OE?

What should volunteers do with monarchs that have OE or other signs of illness?

This post contains affiliate links to materials I truly use for homeschooling. Qualifying purchases provide me with revenue. Thank you for your support!

1 comment:

Renee said...

In doing all of this monarch research, I've discovered that I have swamp milkweed in my yard. That's handy to know! Common milkweed, of course, is also wonderful for monarchs. It has a much wider leaf.