Oh no! Infected Monarch Chrysalis - Experts please...

7 years ago

I picked a 2nd or 3rd instar monarch caterpillar off a plant at a nursery. As soon as it made its chrysalis, I put it in its own container just in case. I am glad I did. It started to darken normally yesterday. This morning I could see the wings, and the chrysalis still looked normal. Then about an hour ago I looked and something was majorly wrong.

I put it in the freezer immediately since I know there's no hope, but want to know what the problem was. It's not OE, I've had that before. I'm thinking chalcid wasps? I'm also very worried about the other 40 - 50 Monarchs I have.... eggs, cats and a few new chrysalids.

Featured Answer

terrene

7 years ago

last modified: 7 years ago

Hi, not an expert here but I've been raising and tagging Monarchs for about 10 years. Occasionally chryalises have turned black and die like the one in your first picture. Also sometimes they have black spots or markings and a seemingly healthy butterfly emerges without incident. Never had a chaclid wasp emerge.

I don't worry much about OE here in the northeast US because I figure that a weak or infected butterfly is not likely to migrate very far and successfully overwinter in Mexico. Not sure if that is actually true though.

Sometimes caterpillars die inexplicably, chrysalises have fallen shortly after pupation, butterflies fail to emerge, or have a deformity when they do. When they die I am bummed for a bit, but there seems to be a small but natural mortality rate at every stage of growth and I try to accept that. And then nature is harsh, in the wild many individuals will be preyed upon even if they are perfectly healthy.

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Comments (6)

Daisy Zone 6b
Original Author
7 years ago
last modified: 7 years ago
Uggggggh. I am now pretty sure it was a chalcid wasp. I looked at another one of my chrysalises - this one formed just a few days ago. I read online to look for black dots on the chrysalis, indicating where the wasp injected the eggs, and there they are :(

I am going to take any of the caterpillars that are now looking to attach and move them to a safe container that has the vents covered with cut up pantyhose. I'll give them a quick water rinse first to knock off any lurking wasps.

My other caterpillars, BSTs and TSTs, will also be moved to safe containers.

I'm so bummed about this, but at least I learned something new and know what to look for. I would have had a heart attack if hundreds of wasps came out of my chrysalises!

Click photo to enlarge. Those random small black dots do not belong there :(

If I have the courage, I will cut open the first chrysalis in this post and take photos. I will leave it in the freezer for a few more days to ensure that anything in there is dead before I cut it open!
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Daisy Zone 6b
Original Author
7 years ago
I was planning on updating today. The frozen chrysalis didn't have any larvae in it that I could see. I had one similar to the second picture with the black marks eclose yesterday and it was fine. So who knows what the marks are.

I have 27 more chrysalids in isolation in wasp proof containers. I'm going to see how things go with them. I'll euthanize any that look really bad. Right now, about half of them have those little black marks, the others look fine. I'm wondering now if I had too many caterpillars in one cage and maybe a virus was affecting some.

I've washed and bleached that cage, which will be used for my upcoming crop of Black Swallowtails. I'm finally getting eggs! I have two good sized metal/screen cages and some smaller plastic "critter cages", so plenty of room for them. They are my favorite butterfly to raise.
Daisy Zone 6b
Original Author
7 years ago
Thought I'd add a photo of my "BICU" . (Butterfly Intensive Care Unit) I made these isolation containers out of inverted plastic wine glasses and panty hose from the dollar store :)
MissSherry
7 years ago
Sorry, Daisy, about the monarchs, but that's a clever BICU!

Sherry
Daisy Zone 6b thanked MissSherry
Kim Walker
4 years ago
Hi! I'm in Australia, I've tried to encourage native butterflies to breed in my citrus. The same species return every year to the same trees. But last year I saw chaclid wasps hanging around but did t know what they were till now. Last year my crysalids had borer holes, and cocoon was indeed empty.😪 this year my first caterpillar I watched cocoon, everyday I checked it, but today were 4 holes and indeed it was empty. I just must not have noticed the initial holes, but can I prevent this? Once the crysalids stage, can I spray w an organic miticide insecticide ie eco oil to keep wasps away but be absorbed by crysalids? Thanks for any