Often they will poop green pellet looking things (called "frass"). This is when they are bigger. Just keep him separate and wait and see.

Is it liquid or solid?
Jennifer

Jennifer, it's liquid. The green stuff has stopped. I've separated him from the other 2; he's laying on his side with his tail curling under.

The two in the other box are not eating the new leaves I put in for them. I'm probably watching too closely!

Sorry for the double post; I couldn't find the first one, so I sent another and then there were 2:)

Hi Sylvia,

Good plan to separate them. Hopefully the other two will make it!

As far as the sick one goes, might be bacteria or polyhedrosis virus - I believe I had the same issue earlier in the season. Tdogmom (CalSherry) knows much more about monarch issue - hopefully she will post!

In the meantime, here's a blurb from "Butterflybreeders.org" I do not know how true the scientific bits are, but they do have a great, easy-to-read list of cat/pupa symptoms, probable causes, and treatments - if any:

"Malnutrition and / or toxic poisoning (pesticides, etc.):

Symptoms shown by the caterpillars:

- High casualty rate during 1st and 2nd instar.

- Caterpillars may tend to walk of the plants in search for better food.

- 3rd  5th instar caterpillars may be found lying on the bottom of your container or pot in a semi-curled position (not their defensive fully curled position). Usually, they will die shortly. Sometimes they will be wiggling on the ground and expelling green fluid out of both ends.

- The caterpillar may not be able to fully pupate, can only push halfway through it's skin.

- The chrysalis may be slightly deformed or have a bumpy texture rather than it's normal smooth shell.

Treatment:

The first three points above are likely caused by pesticides, bleach residue, or some form of toxic poising. The best thing to do is to fully rinse your plants to ensure all residues are removed. If this does not work and symptoms prevail, it may be possible that the plant has a systemic pesticide. At this point, it would be necessary to change your milkweed source. See Appendix B for a picture of our plant rinsing station.

The second two points are likely caused by malnutrition. I would recommend trying to get a hold of a fresher source of milkweed. Usually, the above final two symptoms are found when feeding late season wild milkweed that is somewhat dried and lacking in nutrients. It may not be possible to try a new milkweed source, but it is highly recommended as this is likely your problem."

Below is the link where this came from. Lots more on disease/virus stuff, including OE and polyhedrosis, etc.

Hope this helps -

Sandy :)

Here is a link that might be useful: Caterpillar Disease/Viruses

I keep my cats in separate containers, and two of mine also spewed this green liquid. One that did this (the thrasher; you may have seen my thread about this guy), and he pupated today. After I cleaned out it's container, the diarrea stopped, as did the thrashing. I marked it's container "the thrasher", since I want to watch this one carefully! I don't recall which of my others had the same thing, but I'm not sure if it was the one that recently died (black death) or if it had pupated. I currently have 8 chrysalids, so it could've been any one of the other 7...

I have seen the green diarrhea and weird behavior with pesticide poisoning.
Jennifer

Sandy, thanks for the link; I saved it. I put the cat out of his misery. He was on his side and looked like he was getting dehydrated.

Sylvia